{"id":15471,"date":"2024-11-18T18:18:07","date_gmt":"2024-11-18T10:18:07","guid":{"rendered":"https:\/\/fwq.ai\/blog\/?p=15471"},"modified":"2024-11-18T18:18:07","modified_gmt":"2024-11-18T10:18:07","slug":"docker%e7%9a%84%e5%86%85%e6%a0%b8%e7%9f%a5%e8%af%86%e4%b9%8bnamespace%e8%b5%84%e6%ba%90%e9%9a%94%e7%a6%bb","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/15471\/","title":{"rendered":"Docker\u7684\u5185\u6838\u77e5\u8bc6\u4e4bNamespace\u8d44\u6e90\u9694\u79bb"},"content":{"rendered":"<p>Docker\u8fd9\u4e48\u706b\uff0c\u559c\u6b22\u6280\u672f\u7684\u670b\u53cb\u53ef\u80fd\u4e5f\u4f1a\u60f3\uff0c\u5982\u679c\u8981\u81ea\u5df1\u5b9e\u73b0\u4e00\u4e2a\u8d44\u6e90\u9694\u79bb\u7684\u5bb9\u5668\uff0c\u5e94\u8be5\u4ece\u54ea\u4e9b\u65b9\u9762\u4e0b\u624b\u5462\uff1f\u4e5f\u8bb8\u4f60\u7b2c\u4e00\u53cd\u5e94\u53ef\u80fd\u5c31\u662fchroot\u547d\u4ee4\uff0c\u8fd9\u6761\u547d\u4ee4\u7ed9\u7528\u6237\u6700\u76f4\u89c2\u7684\u611f\u89c9\u5c31\u662f\u4f7f\u7528\u540e\u6839\u76ee\u5f55\/\u7684\u6302\u8f7d\u70b9\u5207\u6362\u4e86\uff0c\u5373\u6587\u4ef6\u7cfb\u7edf\u88ab\u9694\u79bb\u4e86\u3002\u7136\u540e\uff0c\u4e3a\u4e86\u5728\u5206\u5e03\u5f0f\u7684\u73af\u5883\u4e0b\u8fdb\u884c\u901a\u4fe1\u548c\u5b9a\u4f4d\uff0c\u5bb9\u5668\u5fc5\u7136\u9700\u8981\u4e00\u4e2a\u72ec\u7acb\u7684IP\u3001\u7aef\u53e3\u3001\u8def\u7531\u7b49\u7b49\uff0c\u81ea\u7136\u5c31\u60f3\u5230\u4e86\u7f51\u7edc\u7684\u9694\u79bb\u3002\u540c\u65f6\uff0c\u4f60\u7684\u5bb9\u5668\u8fd8\u9700\u8981\u4e00\u4e2a\u72ec\u7acb\u7684\u4e3b\u673a\u540d\u4ee5\u4fbf\u5728\u7f51\u7edc\u4e2d\u6807\u8bc6\u81ea\u5df1\u3002\u60f3\u5230\u7f51\u7edc\uff0c\u987a\u5176\u81ea\u7136\u5c31\u60f3\u5230\u901a\u4fe1\uff0c\u4e5f\u5c31\u60f3\u5230\u4e86\u8fdb\u7a0b\u95f4\u901a\u4fe1\u7684\u9694\u79bb\u3002\u53ef\u80fd\u4f60\u4e5f\u60f3\u5230\u4e86\u6743\u9650\u7684\u95ee\u9898\uff0c\u5bf9\u7528\u6237\u548c\u7528\u6237\u7ec4\u7684\u9694\u79bb\u5c31\u5b9e\u73b0\u4e86\u7528\u6237\u6743\u9650\u7684\u9694\u79bb\u3002\u6700\u540e\uff0c\u8fd0\u884c\u5728\u5bb9\u5668\u4e2d\u7684\u5e94\u7528\u9700\u8981\u6709\u81ea\u5df1\u7684PID,\u81ea\u7136\u4e5f\u9700\u8981\u4e0e\u5bbf\u4e3b\u673a\u4e2d\u7684PID\u8fdb\u884c\u9694\u79bb\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>\u7531\u6b64\uff0c\u6211\u4eec\u57fa\u672c\u4e0a\u5b8c\u6210\u4e86\u4e00\u4e2a\u5bb9\u5668\u6240\u9700\u8981\u505a\u7684\u516d\u9879\u9694\u79bb\uff0cLinux\u5185\u6838\u4e2d\u5c31\u63d0\u4f9b\u4e86\u8fd9\u516d\u79cdnamespace\u9694\u79bb\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u5982\u4e0b\u8868\u6240\u793a\u3002<\/p>\n<table border=\"1\" width=\"489\" cellspacing=\"0\" cellpadding=\"2\">\n<tbody>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">Namespace<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">\u7cfb\u7edf\u8c03\u7528\u53c2\u6570<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u9694\u79bb\u5185\u5bb9<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">UTS<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWUTS<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u4e3b\u673a\u540d\u4e0e\u57df\u540d<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">IPC<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWIPC<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u4fe1\u53f7\u91cf\u3001\u6d88\u606f\u961f\u5217\u548c\u5171\u4eab\u5185\u5b58<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">PID<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWPID<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u8fdb\u7a0b\u7f16\u53f7<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">Network<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWNET<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u7f51\u7edc\u8bbe\u5907\u3001\u7f51\u7edc\u6808\u3001\u7aef\u53e3\u7b49\u7b49<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">Mount<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWNS<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u6302\u8f7d\u70b9\uff08\u6587\u4ef6\u7cfb\u7edf\uff09<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"101\">\n<p align=\"center\">User<\/p>\n<\/td>\n<td valign=\"top\" width=\"168\">\n<p align=\"center\">CLONE_NEWUSER<\/p>\n<\/td>\n<td valign=\"top\" width=\"218\">\n<p align=\"center\">\u7528\u6237\u548c\u7528\u6237\u7ec4<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u8868 namespace\u516d\u9879\u9694\u79bb<\/p>\n<p>\u5b9e\u9645\u4e0a\uff0cLinux\u5185\u6838\u5b9e\u73b0namespace\u7684\u4e3b\u8981\u76ee\u7684\u5c31\u662f\u4e3a\u4e86\u5b9e\u73b0\u8f7b\u91cf\u7ea7\u865a\u62df\u5316\uff08\u5bb9\u5668\uff09\u670d\u52a1\u3002\u5728\u540c\u4e00\u4e2anamespace\u4e0b\u7684\u8fdb\u7a0b\u53ef\u4ee5\u611f\u77e5\u5f7c\u6b64\u7684\u53d8\u5316\uff0c\u800c\u5bf9\u5916\u754c\u7684\u8fdb\u7a0b\u4e00\u65e0\u6240\u77e5\u3002\u8fd9\u6837\u5c31\u53ef\u4ee5\u8ba9\u5bb9\u5668\u4e2d\u7684\u8fdb\u7a0b\u4ea7\u751f\u9519\u89c9\uff0c\u4eff\u4f5b\u81ea\u5df1\u7f6e\u8eab\u4e8e\u4e00\u4e2a\u72ec\u7acb\u7684\u7cfb\u7edf\u73af\u5883\u4e2d\uff0c\u4ee5\u6b64\u8fbe\u5230\u72ec\u7acb\u548c\u9694\u79bb\u7684\u76ee\u7684\u3002<\/p>\n<p>\u9700\u8981\u8bf4\u660e\u7684\u662f\uff0c\u672c\u6587\u6240\u8ba8\u8bba\u7684namespace\u5b9e\u73b0\u9488\u5bf9\u7684\u5747\u662fLinux\u5185\u68383.8\u53ca\u5176\u4ee5\u540e\u7684\u7248\u672c\u3002\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u9996\u5148\u4ecb\u7ecd\u4f7f\u7528namespace\u7684API\uff0c\u7136\u540e\u9488\u5bf9\u8fd9\u516d\u79cdnamespace\u8fdb\u884c\u9010\u4e00\u8bb2\u89e3\uff0c\u5e76\u901a\u8fc7\u7a0b\u5e8f\u8ba9\u4f60\u4eb2\u8eab\u611f\u53d7\u4e00\u4e0b\u8fd9\u4e9b\u9694\u79bb\u6548\u679c\uff08\u53c2\u8003\u81ea<a href=\"http:\/\/lwn.net\/Articles\/531114\/\">http:\/\/lwn.net\/Articles\/531114\/<\/a>\uff09\u3002<\/p>\n<h2>1. \u8c03\u7528namespace\u7684API<\/h2>\n<p>namespace\u7684API\u5305\u62ecclone()\u3001setns()\u4ee5\u53caunshare()\uff0c\u8fd8\u6709\/proc\u4e0b\u7684\u90e8\u5206\u6587\u4ef6\u3002\u4e3a\u4e86\u786e\u5b9a\u9694\u79bb\u7684\u5230\u5e95\u662f\u54ea\u79cdnamespace\uff0c\u5728\u4f7f\u7528\u8fd9\u4e9bAPI\u65f6\uff0c\u901a\u5e38\u9700\u8981\u6307\u5b9a\u4ee5\u4e0b\u516d\u4e2a\u5e38\u6570\u7684\u4e00\u4e2a\u6216\u591a\u4e2a\uff0c\u901a\u8fc7|\uff08\u4f4d\u6216\uff09\u64cd\u4f5c\u6765\u5b9e\u73b0\u3002\u4f60\u53ef\u80fd\u5df2\u7ecf\u5728\u4e0a\u9762\u7684\u8868\u683c\u4e2d\u6ce8\u610f\u5230\uff0c\u8fd9\u516d\u4e2a\u53c2\u6570\u5206\u522b\u662fCLONE_NEWIPC\u3001CLONE_NEWNS\u3001CLONE_NEWNET\u3001CLONE_NEWPID\u3001CLONE_NEWUSER\u548cCLONE_NEWUTS\u3002<\/p>\n<h3>\uff081\uff09\u901a\u8fc7clone()\u521b\u5efa\u65b0\u8fdb\u7a0b\u7684\u540c\u65f6\u521b\u5efanamespace<\/h3>\n<p>\u4f7f\u7528clone()\u6765\u521b\u5efa\u4e00\u4e2a\u72ec\u7acbnamespace\u7684\u8fdb\u7a0b\u662f\u6700\u5e38\u89c1\u505a\u6cd5\uff0c\u5b83\u7684\u8c03\u7528\u65b9\u5f0f\u5982\u4e0b\u3002<\/p>\n<pre>int clone(int (*child_func)(void *), void *child_stack, int flags, void *arg);<\/pre>\n<p>clone()\u5b9e\u9645\u4e0a\u662f\u4f20\u7edfUNIX\u7cfb\u7edf\u8c03\u7528fork()\u7684\u4e00\u79cd\u66f4\u901a\u7528\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u5b83\u53ef\u4ee5\u901a\u8fc7flags\u6765\u63a7\u5236\u4f7f\u7528\u591a\u5c11\u529f\u80fd\u3002\u4e00\u5171\u6709\u4e8c\u5341\u591a\u79cdCLONE_*\u7684flag\uff08\u6807\u5fd7\u4f4d\uff09\u53c2\u6570\u7528\u6765\u63a7\u5236clone\u8fdb\u7a0b\u7684\u65b9\u65b9\u9762\u9762\uff08\u5982\u662f\u5426\u4e0e\u7236\u8fdb\u7a0b\u5171\u4eab\u865a\u62df\u5185\u5b58\u7b49\u7b49\uff09\uff0c\u4e0b\u9762\u5916\u9762\u9010\u4e00\u8bb2\u89e3clone\u51fd\u6570\u4f20\u5165\u7684\u53c2\u6570\u3002<\/p>\n<ul>\n<li>\u53c2\u6570child_func\u4f20\u5165\u5b50\u8fdb\u7a0b\u8fd0\u884c\u7684\u7a0b\u5e8f\u4e3b\u51fd\u6570\u3002<\/li>\n<li>\u53c2\u6570child_stack\u4f20\u5165\u5b50\u8fdb\u7a0b\u4f7f\u7528\u7684\u6808\u7a7a\u95f4<\/li>\n<li>\u53c2\u6570flags\u8868\u793a\u4f7f\u7528\u54ea\u4e9bCLONE_*\u6807\u5fd7\u4f4d<\/li>\n<li>\u53c2\u6570args\u5219\u53ef\u7528\u4e8e\u4f20\u5165\u7528\u6237\u53c2\u6570<\/li>\n<\/ul>\n<p>\u5728\u540e\u7eed\u7684\u5185\u5bb9\u4e2d\u5c06\u4f1a\u6709\u4f7f\u7528clone()\u7684\u5b9e\u9645\u7a0b\u5e8f\u53ef\u4f9b\u5927\u5bb6\u53c2\u8003\u3002<\/p>\n<h3>\uff082\uff09\u67e5\u770b\/proc\/[pid]\/ns\u6587\u4ef6<\/h3>\n<p>\u4ece3.8\u7248\u672c\u7684\u5185\u6838\u5f00\u59cb\uff0c\u7528\u6237\u5c31\u53ef\u4ee5\u5728\/proc\/[pid]\/ns\u6587\u4ef6\u4e0b\u770b\u5230\u6307\u5411\u4e0d\u540cnamespace\u53f7\u7684\u6587\u4ef6\uff0c\u6548\u679c\u5982\u4e0b\u6240\u793a\uff0c\u5f62\u5982[4026531839]\u8005\u5373\u4e3anamespace\u53f7\u3002<\/p>\n<pre>$ ls -l \/proc\/$$\/ns         &lt;&lt;-- $$ \u8868\u793a\u5e94\u7528\u7684PID\r\ntotal 0\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 ipc -&gt; ipc:[4026531839]\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 mnt -&gt; mnt:[4026531840]\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 net -&gt; net:[4026531956]\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 pid -&gt; pid:[4026531836]\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 user-&gt;user:[4026531837]\r\nlrwxrwxrwx. 1 mtk mtk 0 Jan  8 04:12 uts -&gt; uts:[4026531838]<\/pre>\n<p>\u5982\u679c\u4e24\u4e2a\u8fdb\u7a0b\u6307\u5411\u7684namespace\u7f16\u53f7\u76f8\u540c\uff0c\u5c31\u8bf4\u660e\u4ed6\u4eec\u5728\u540c\u4e00\u4e2anamespace\u4e0b\uff0c\u5426\u5219\u5219\u5728\u4e0d\u540cnamespace\u91cc\u9762\u3002\/proc\/[pid]\/ns\u7684\u53e6\u5916\u4e00\u4e2a\u4f5c\u7528\u662f\uff0c\u4e00\u65e6\u6587\u4ef6\u88ab\u6253\u5f00\uff0c\u53ea\u8981\u6253\u5f00\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff08fd\uff09\u5b58\u5728\uff0c\u90a3\u4e48\u5c31\u7b97PID\u6240\u5c5e\u7684\u6240\u6709\u8fdb\u7a0b\u90fd\u5df2\u7ecf\u7ed3\u675f\uff0c\u521b\u5efa\u7684namespace\u5c31\u4f1a\u4e00\u76f4\u5b58\u5728\u3002\u90a3\u5982\u4f55\u6253\u5f00\u6587\u4ef6\u63cf\u8ff0\u7b26\u5462\uff1f\u628a\/proc\/[pid]\/ns\u76ee\u5f55\u6302\u8f7d\u8d77\u6765\u5c31\u53ef\u4ee5\u8fbe\u5230\u8fd9\u4e2a\u6548\u679c\uff0c\u547d\u4ee4\u5982\u4e0b\u3002<\/p>\n<pre># touch ~\/uts\r\n# mount --bind \/proc\/27514\/ns\/uts ~\/uts<\/pre>\n<p>\u5982\u679c\u4f60\u770b\u5230\u7684\u5185\u5bb9\u4e0e\u672c\u6587\u6240\u63cf\u8ff0\u7684\u4e0d\u7b26\uff0c\u90a3\u4e48\u8bf4\u660e\u4f60\u4f7f\u7528\u7684\u5185\u6838\u57283.8\u7248\u672c\u4ee5\u524d\u3002\u8be5\u76ee\u5f55\u4e0b\u5b58\u5728\u7684\u53ea\u6709ipc\u3001net\u548cuts\uff0c\u5e76\u4e14\u4ee5\u786c\u94fe\u63a5\u5b58\u5728\u3002<\/p>\n<h3>\uff083\uff09\u901a\u8fc7setns()\u52a0\u5165\u4e00\u4e2a\u5df2\u7ecf\u5b58\u5728\u7684namespace<\/h3>\n<p>\u4e0a\u6587\u521a\u63d0\u5230\uff0c\u5728\u8fdb\u7a0b\u90fd\u7ed3\u675f\u7684\u60c5\u51b5\u4e0b\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7\u6302\u8f7d\u7684\u5f62\u5f0f\u628anamespace\u4fdd\u7559\u4e0b\u6765\uff0c\u4fdd\u7559namespace\u7684\u76ee\u7684\u81ea\u7136\u662f\u4e3a\u4ee5\u540e\u6709\u8fdb\u7a0b\u52a0\u5165\u505a\u51c6\u5907\u3002\u901a\u8fc7setns()\u7cfb\u7edf\u8c03\u7528\uff0c\u4f60\u7684\u8fdb\u7a0b\u4ece\u539f\u5148\u7684namespace\u52a0\u5165\u6211\u4eec\u51c6\u5907\u597d\u7684\u65b0namespace\uff0c\u4f7f\u7528\u65b9\u6cd5\u5982\u4e0b\u3002<\/p>\n<pre>int setns(int fd, int nstype);<\/pre>\n<ul>\n<li>\u53c2\u6570fd\u8868\u793a\u6211\u4eec\u8981\u52a0\u5165\u7684namespace\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002\u4e0a\u6587\u5df2\u7ecf\u63d0\u5230\uff0c\u5b83\u662f\u4e00\u4e2a\u6307\u5411\/proc\/[pid]\/ns\u76ee\u5f55\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u53ef\u4ee5\u901a\u8fc7\u76f4\u63a5\u6253\u5f00\u8be5\u76ee\u5f55\u4e0b\u7684\u94fe\u63a5\u6216\u8005\u6253\u5f00\u4e00\u4e2a\u6302\u8f7d\u4e86\u8be5\u76ee\u5f55\u4e0b\u94fe\u63a5\u7684\u6587\u4ef6\u5f97\u5230\u3002<\/li>\n<li>\u53c2\u6570nstype\u8ba9\u8c03\u7528\u8005\u53ef\u4ee5\u53bb\u68c0\u67e5fd\u6307\u5411\u7684namespace\u7c7b\u578b\u662f\u5426\u7b26\u5408\u6211\u4eec\u5b9e\u9645\u7684\u8981\u6c42\u3002\u5982\u679c\u586b0\u8868\u793a\u4e0d\u68c0\u67e5\u3002<\/li>\n<\/ul>\n<p>\u4e3a\u4e86\u628a\u6211\u4eec\u521b\u5efa\u7684namespace\u5229\u7528\u8d77\u6765\uff0c\u6211\u4eec\u9700\u8981\u5f15\u5165execve()\u7cfb\u5217\u51fd\u6570\uff0c\u8fd9\u4e2a\u51fd\u6570\u53ef\u4ee5\u6267\u884c\u7528\u6237\u547d\u4ee4\uff0c\u6700\u5e38\u7528\u7684\u5c31\u662f\u8c03\u7528\/bin\/bash\u5e76\u63a5\u53d7\u53c2\u6570\uff0c\u8fd0\u884c\u8d77\u4e00\u4e2ashell\uff0c\u7528\u6cd5\u5982\u4e0b\u3002<\/p>\n<pre>fd = open(argv[1], O_RDONLY);   \/* \u83b7\u53d6namespace\u6587\u4ef6\u63cf\u8ff0\u7b26 *\/\r\nsetns(fd, 0);                   \/* \u52a0\u5165\u65b0\u7684namespace *\/\r\nexecvp(argv[2], &amp;argv[2]);      \/* \u6267\u884c\u7a0b\u5e8f *\/<\/pre>\n<p>\u5047\u8bbe\u7f16\u8bd1\u540e\u7684\u7a0b\u5e8f\u540d\u79f0\u4e3asetns\u3002<\/p>\n<pre># .\/setns ~\/uts \/bin\/bash   # ~\/uts \u662f\u7ed1\u5b9a\u7684\/proc\/27514\/ns\/uts<\/pre>\n<p>\u81f3\u6b64\uff0c\u4f60\u5c31\u53ef\u4ee5\u5728\u65b0\u7684\u547d\u540d\u7a7a\u95f4\u4e2d\u6267\u884cshell\u547d\u4ee4\u4e86\uff0c\u5728\u4e0b\u6587\u4e2d\u4f1a\u591a\u6b21\u4f7f\u7528\u8fd9\u79cd\u65b9\u5f0f\u6765\u6f14\u793a\u9694\u79bb\u7684\u6548\u679c\u3002<\/p>\n<h3>\uff084\uff09\u901a\u8fc7unshare()\u5728\u539f\u5148\u8fdb\u7a0b\u4e0a\u8fdb\u884cnamespace\u9694\u79bb<\/h3>\n<p>\u6700\u540e\u8981\u63d0\u7684\u7cfb\u7edf\u8c03\u7528\u662funshare()\uff0c\u5b83\u8ddfclone()\u5f88\u50cf\uff0c\u4e0d\u540c\u7684\u662f\uff0cunshare()\u8fd0\u884c\u5728\u539f\u5148\u7684\u8fdb\u7a0b\u4e0a\uff0c\u4e0d\u9700\u8981\u542f\u52a8\u4e00\u4e2a\u65b0\u8fdb\u7a0b\uff0c\u4f7f\u7528\u65b9\u6cd5\u5982\u4e0b\u3002<\/p>\n<pre>int unshare(int flags);<\/pre>\n<p>\u8c03\u7528unshare()\u7684\u4e3b\u8981\u4f5c\u7528\u5c31\u662f\u4e0d\u542f\u52a8\u4e00\u4e2a\u65b0\u8fdb\u7a0b\u5c31\u53ef\u4ee5\u8d77\u5230\u9694\u79bb\u7684\u6548\u679c\uff0c\u76f8\u5f53\u4e8e\u8df3\u51fa\u539f\u5148\u7684namespace\u8fdb\u884c\u64cd\u4f5c\u3002\u8fd9\u6837\uff0c\u4f60\u5c31\u53ef\u4ee5\u5728\u539f\u8fdb\u7a0b\u8fdb\u884c\u4e00\u4e9b\u9700\u8981\u9694\u79bb\u7684\u64cd\u4f5c\u3002Linux\u4e2d\u81ea\u5e26\u7684unshare\u547d\u4ee4\uff0c\u5c31\u662f\u901a\u8fc7unshare()\u7cfb\u7edf\u8c03\u7528\u5b9e\u73b0\u7684\uff0c\u6709\u5174\u8da3\u7684\u8bfb\u8005\u53ef\u4ee5\u5728\u7f51\u4e0a\u641c\u7d22\u4e00\u4e0b\u8fd9\u4e2a\u547d\u4ee4\u7684\u4f5c\u7528\u3002<\/p>\n<h3>\uff085\uff09\u5ef6\u4f38\u9605\u8bfb\uff1afork\uff08\uff09\u7cfb\u7edf\u8c03\u7528<\/h3>\n<p>\u7cfb\u7edf\u8c03\u7528\u51fd\u6570fork()\u5e76\u4e0d\u5c5e\u4e8enamespace\u7684API\uff0c\u6240\u4ee5\u8fd9\u90e8\u5206\u5185\u5bb9\u5c5e\u4e8e\u5ef6\u4f38\u9605\u8bfb\uff0c\u5982\u679c\u8bfb\u8005\u5df2\u7ecf\u5bf9fork()\u6709\u8db3\u591f\u7684\u4e86\u89e3\uff0c\u90a3\u5927\u53ef\u8df3\u8fc7\u3002<\/p>\n<p>\u5f53\u7a0b\u5e8f\u8c03\u7528fork\uff08\uff09\u51fd\u6570\u65f6\uff0c\u7cfb\u7edf\u4f1a\u521b\u5efa\u65b0\u7684\u8fdb\u7a0b\uff0c\u4e3a\u5176\u5206\u914d\u8d44\u6e90\uff0c\u4f8b\u5982\u5b58\u50a8\u6570\u636e\u548c\u4ee3\u7801\u7684\u7a7a\u95f4\u3002\u7136\u540e\u628a\u539f\u6765\u7684\u8fdb\u7a0b\u7684\u6240\u6709\u503c\u90fd\u590d\u5236\u5230\u65b0\u7684\u8fdb\u7a0b\u4e2d\uff0c\u53ea\u6709\u5c11\u91cf\u6570\u503c\u4e0e\u539f\u6765\u7684\u8fdb\u7a0b\u503c\u4e0d\u540c\uff0c\u76f8\u5f53\u4e8e\u514b\u9686\u4e86\u4e00\u4e2a\u81ea\u5df1\u3002\u90a3\u4e48\u7a0b\u5e8f\u7684\u540e\u7eed\u4ee3\u7801\u903b\u8f91\u8981\u5982\u4f55\u533a\u5206\u81ea\u5df1\u662f\u65b0\u8fdb\u7a0b\u8fd8\u662f\u7236\u8fdb\u7a0b\u5462\uff1f<\/p>\n<p>fork()\u7684\u795e\u5947\u4e4b\u5904\u5728\u4e8e\u5b83\u4ec5\u4ec5\u88ab\u8c03\u7528\u4e00\u6b21\uff0c\u5374\u80fd\u591f\u8fd4\u56de\u4e24\u6b21\uff08\u7236\u8fdb\u7a0b\u4e0e\u5b50\u8fdb\u7a0b\u5404\u8fd4\u56de\u4e00\u6b21\uff09\uff0c\u901a\u8fc7\u8fd4\u56de\u503c\u7684\u4e0d\u540c\u5c31\u53ef\u4ee5\u8fdb\u884c\u533a\u5206\u7236\u8fdb\u7a0b\u4e0e\u5b50\u8fdb\u7a0b\u3002\u5b83\u53ef\u80fd\u6709\u4e09\u79cd\u4e0d\u540c\u7684\u8fd4\u56de\u503c\uff1a<\/p>\n<ul>\n<li>\u5728\u7236\u8fdb\u7a0b\u4e2d\uff0cfork\u8fd4\u56de\u65b0\u521b\u5efa\u5b50\u8fdb\u7a0b\u7684\u8fdb\u7a0bID<\/li>\n<li>\u5728\u5b50\u8fdb\u7a0b\u4e2d\uff0cfork\u8fd4\u56de0<\/li>\n<li>\u5982\u679c\u51fa\u73b0\u9519\u8bef\uff0cfork\u8fd4\u56de\u4e00\u4e2a\u8d1f\u503c<\/li>\n<\/ul>\n<p>\u4e0b\u9762\u7ed9\u51fa\u4e00\u6bb5\u5b9e\u4f8b\u4ee3\u7801\uff0c\u547d\u540d\u4e3afork_example.c\u3002<\/p>\n<pre>#include &lt;unistd.h&gt;\r\n#include &lt;stdio.h&gt;\r\nint main (){\r\n    pid_t fpid; \/\/fpid\u8868\u793afork\u51fd\u6570\u8fd4\u56de\u7684\u503c\r\n    int count=0;\r\n    fpid=fork();\r\n    if (fpid &lt; 0)printf(\"error in fork!\");\r\n    else if (fpid == 0) {\r\n        printf(\"I am child. Process id is %d\/n\",getpid());\r\n    }\r\n    else {\r\n        printf(\"i am parent. Process id is %d\/n\",getpid());\r\n    }\r\n    return 0;\r\n}<\/pre>\n<p>\u7f16\u8bd1\u5e76\u6267\u884c\uff0c\u7ed3\u679c\u5982\u4e0b\u3002<\/p>\n<pre>root@local:~# gcc -Wall fork_example.c &amp;&amp; .\/a.out\r\nI am parent. Process id is 28365\r\nI am child. Process id is 28366<\/pre>\n<p>\u4f7f\u7528fork()\u540e\uff0c\u7236\u8fdb\u7a0b\u6709\u4e49\u52a1\u76d1\u63a7\u5b50\u8fdb\u7a0b\u7684\u8fd0\u884c\u72b6\u6001\uff0c\u5e76\u5728\u5b50\u8fdb\u7a0b\u9000\u51fa\u540e\u81ea\u5df1\u624d\u80fd\u6b63\u5e38\u9000\u51fa\uff0c\u5426\u5219\u5b50\u8fdb\u7a0b\u5c31\u4f1a\u6210\u4e3a\u201c\u5b64\u513f\u201d\u8fdb\u7a0b\u3002<\/p>\n<p>\u4e0b\u9762\u6211\u4eec\u5c06\u5206\u522b\u5bf9\u516d\u79cdnamespace\u8fdb\u884c\u8be6\u7ec6\u89e3\u6790\u3002<\/p>\n<h2>2. UTS\uff08UNIX Time-sharing System\uff09namespace<\/h2>\n<p>UTS namespace\u63d0\u4f9b\u4e86\u4e3b\u673a\u540d\u548c\u57df\u540d\u7684\u9694\u79bb\uff0c\u8fd9\u6837\u6bcf\u4e2a\u5bb9\u5668\u5c31\u53ef\u4ee5\u62e5\u6709\u4e86\u72ec\u7acb\u7684\u4e3b\u673a\u540d\u548c\u57df\u540d\uff0c\u5728\u7f51\u7edc\u4e0a\u53ef\u4ee5\u88ab\u89c6\u4f5c\u4e00\u4e2a\u72ec\u7acb\u7684\u8282\u70b9\u800c\u975e\u5bbf\u4e3b\u673a\u4e0a\u7684\u4e00\u4e2a\u8fdb\u7a0b\u3002<\/p>\n<p>\u4e0b\u9762\u6211\u4eec\u901a\u8fc7\u4ee3\u7801\u6765\u611f\u53d7\u4e00\u4e0bUTS\u9694\u79bb\u7684\u6548\u679c\uff0c\u9996\u5148\u9700\u8981\u4e00\u4e2a\u7a0b\u5e8f\u7684\u9aa8\u67b6\uff0c\u5982\u4e0b\u6240\u793a\u3002\u6253\u5f00\u7f16\u8f91\u5668\u521b\u5efauts.c\u6587\u4ef6\uff0c\u8f93\u5165\u5982\u4e0b\u4ee3\u7801\u3002<\/p>\n<pre>#define _GNU_SOURCE\r\n#include &lt;sys\/types.h&gt;\r\n#include &lt;sys\/wait.h&gt;\r\n#include &lt;stdio.h&gt;\r\n#include &lt;sched.h&gt;\r\n#include &lt;signal.h&gt;\r\n#include &lt;unistd.h&gt;\r\n\r\n#define STACK_SIZE (1024 * 1024)\r\n\r\nstatic char child_stack[STACK_SIZE];\r\nchar* const child_args[] = {\r\n  \"\/bin\/bash\",\r\n  NULL\r\n};\r\n\r\nint child_main(void* args) {\r\n  printf(\"\u5728\u5b50\u8fdb\u7a0b\u4e2d!\\n\");\r\n  execv(child_args[0], child_args);\r\n  return 1;\r\n}\r\n\r\nint main() {\r\n  printf(\"\u7a0b\u5e8f\u5f00\u59cb: \\n\");\r\n  int child_pid = clone(child_main, child_stack + STACK_SIZE, SIGCHLD, NULL);\r\n  waitpid(child_pid, NULL, 0);\r\n  printf(\"\u5df2\u9000\u51fa\\n\");\r\n  return 0;\r\n}<\/pre>\n<p>\u7f16\u8bd1\u5e76\u8fd0\u884c\u4e0a\u8ff0\u4ee3\u7801\uff0c\u6267\u884c\u5982\u4e0b\u547d\u4ee4\uff0c\u6548\u679c\u5982\u4e0b\u3002<\/p>\n<pre>root@local:~# gcc -Wall uts.c -o uts.o &amp;&amp; .\/uts.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\nroot@local:~# exit\r\nexit\r\n\u5df2\u9000\u51fa\r\nroot@local:~#<\/pre>\n<p>\u4e0b\u9762\uff0c\u6211\u4eec\u5c06\u4fee\u6539\u4ee3\u7801\uff0c\u52a0\u5165UTS\u9694\u79bb\u3002\u8fd0\u884c\u4ee3\u7801\u9700\u8981root\u6743\u9650\uff0c\u4e3a\u4e86\u9632\u6b62\u666e\u901a\u7528\u6237\u4efb\u610f\u4fee\u6539\u7cfb\u7edf\u4e3b\u673a\u540d\u5bfc\u81f4set-user-ID\u76f8\u5173\u7684\u5e94\u7528\u8fd0\u884c\u51fa\u9519\u3002<\/p>\n<pre>\/\/[...]\r\nint child_main(void* arg) {\r\n  printf(\"\u5728\u5b50\u8fdb\u7a0b\u4e2d!\\n\");\r\n  sethostname(\"Changed Namespace\", 12);\r\n  execv(child_args[0], child_args);\r\n  return 1;\r\n}\r\n\r\nint main() {\r\n\/\/[...]\r\nint child_pid = clone(child_main, child_stack+STACK_SIZE,\r\n    CLONE_NEWUTS | SIGCHLD, NULL);\r\n\/\/[...]\r\n}<\/pre>\n<p>\u518d\u6b21\u8fd0\u884c\u53ef\u4ee5\u770b\u5230hostname\u5df2\u7ecf\u53d8\u5316\u3002<\/p>\n<pre>root@local:~# gcc -Wall namespace.c -o main.o &amp;&amp; .\/main.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\nroot@NewNamespace:~# exit\r\nexit\r\n\u5df2\u9000\u51fa\r\nroot@local:~#  &lt;- \u56de\u5230\u539f\u6765\u7684hostname<\/pre>\n<p>\u4e5f\u8bb8\u6709\u8bfb\u8005\u8bd5\u7740\u4e0d\u52a0CLONE_NEWUTS\u53c2\u6570\u8fd0\u884c\u4e0a\u8ff0\u4ee3\u7801\uff0c\u53d1\u73b0\u4e3b\u673a\u540d\u4e5f\u53d8\u4e86\uff0c\u8f93\u5165exit\u4ee5\u540e\u4e3b\u673a\u540d\u4e5f\u4f1a\u53d8\u56de\u6765\uff0c\u4f3c\u4e4e\u6ca1\u4ec0\u4e48\u533a\u522b\u3002\u5b9e\u9645\u4e0a\u4e0d\u52a0CLONE_NEWUTS\u53c2\u6570\u8fdb\u884c\u9694\u79bb\u800c\u4f7f\u7528sethostname\u5df2\u7ecf\u628a\u5bbf\u4e3b\u673a\u7684\u4e3b\u673a\u540d\u6539\u6389\u4e86\u3002\u4f60\u770b\u5230exit\u9000\u51fa\u540e\u8fd8\u539f\u53ea\u662f\u56e0\u4e3abash\u53ea\u5728\u521a\u767b\u5f55\u7684\u65f6\u5019\u8bfb\u53d6\u4e00\u6b21UTS\uff0c\u5f53\u4f60\u91cd\u65b0\u767b\u9646\u6216\u8005\u4f7f\u7528uname\u547d\u4ee4\u8fdb\u884c\u67e5\u770b\u65f6\uff0c\u5c31\u4f1a\u53d1\u73b0\u4ea7\u751f\u4e86\u53d8\u5316\u3002<\/p>\n<p>Docker\u4e2d\uff0c\u6bcf\u4e2a\u955c\u50cf\u57fa\u672c\u90fd\u4ee5\u81ea\u5df1\u6240\u63d0\u4f9b\u7684\u670d\u52a1\u547d\u540d\u4e86\u81ea\u5df1\u7684hostname\u800c\u6ca1\u6709\u5bf9\u5bbf\u4e3b\u673a\u4ea7\u751f\u4efb\u4f55\u5f71\u54cd\uff0c\u7528\u7684\u5c31\u662f\u8fd9\u4e2a\u539f\u7406\u3002<\/p>\n<h2>3. IPC\uff08Interprocess Communication\uff09namespace<\/h2>\n<p>\u5bb9\u5668\u4e2d\u8fdb\u7a0b\u95f4\u901a\u4fe1\u91c7\u7528\u7684\u65b9\u6cd5\u5305\u62ec\u5e38\u89c1\u7684\u4fe1\u53f7\u91cf\u3001\u6d88\u606f\u961f\u5217\u548c\u5171\u4eab\u5185\u5b58\u3002\u7136\u800c\u4e0e\u865a\u62df\u673a\u4e0d\u540c\u7684\u662f\uff0c\u5bb9\u5668\u5185\u90e8\u8fdb\u7a0b\u95f4\u901a\u4fe1\u5bf9\u5bbf\u4e3b\u673a\u6765\u8bf4\uff0c\u5b9e\u9645\u4e0a\u662f\u5177\u6709\u76f8\u540cPID namespace\u4e2d\u7684\u8fdb\u7a0b\u95f4\u901a\u4fe1\uff0c\u56e0\u6b64\u9700\u8981\u4e00\u4e2a\u552f\u4e00\u7684\u6807\u8bc6\u7b26\u6765\u8fdb\u884c\u533a\u522b\u3002\u7533\u8bf7IPC\u8d44\u6e90\u5c31\u7533\u8bf7\u4e86\u8fd9\u6837\u4e00\u4e2a\u5168\u5c40\u552f\u4e00\u768432\u4f4dID\uff0c\u6240\u4ee5IPC namespace\u4e2d\u5b9e\u9645\u4e0a\u5305\u542b\u4e86\u7cfb\u7edfIPC\u6807\u8bc6\u7b26\u4ee5\u53ca\u5b9e\u73b0POSIX\u6d88\u606f\u961f\u5217\u7684\u6587\u4ef6\u7cfb\u7edf\u3002\u5728\u540c\u4e00\u4e2aIPC namespace\u4e0b\u7684\u8fdb\u7a0b\u5f7c\u6b64\u53ef\u89c1\uff0c\u800c\u4e0e\u5176\u4ed6\u7684IPC namespace\u4e0b\u7684\u8fdb\u7a0b\u5219\u4e92\u76f8\u4e0d\u53ef\u89c1\u3002<\/p>\n<p>IPC namespace\u5728\u4ee3\u7801\u4e0a\u7684\u53d8\u5316\u4e0eUTS namespace\u76f8\u4f3c\uff0c\u53ea\u662f\u6807\u8bc6\u4f4d\u6709\u6240\u53d8\u5316\uff0c\u9700\u8981\u52a0\u4e0aCLONE_NEWIPC\u53c2\u6570\u3002\u4e3b\u8981\u6539\u52a8\u5982\u4e0b\uff0c\u5176\u4ed6\u90e8\u4f4d\u4e0d\u53d8\uff0c\u7a0b\u5e8f\u540d\u79f0\u6539\u4e3aipc.c\u3002<\/p>\n<pre>\/\/[...]\r\nint child_pid = clone(child_main, child_stack+STACK_SIZE,\r\n           CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD, NULL);\r\n\/\/[...]<\/pre>\n<p>\u6211\u4eec\u9996\u5148\u5728shell\u4e2d\u4f7f\u7528ipcmk -Q\u547d\u4ee4\u521b\u5efa\u4e00\u4e2amessage queue\u3002<\/p>\n<pre>root@local:~# ipcmk -Q\r\nMessage queue id: 32769<\/pre>\n<p>\u901a\u8fc7ipcs -q\u53ef\u4ee5\u67e5\u770b\u5230\u5df2\u7ecf\u5f00\u542f\u7684message queue\uff0c\u5e8f\u53f7\u4e3a32769\u3002<\/p>\n<pre>root@local:~# ipcs -q\r\n------ Message Queues --------\r\nkey        msqid   owner   perms   used-bytes   messages\r\n0x4cf5e29f 32769   root    644     0            0<\/pre>\n<p>\u7136\u540e\u6211\u4eec\u53ef\u4ee5\u7f16\u8bd1\u8fd0\u884c\u52a0\u5165\u4e86IPC namespace\u9694\u79bb\u7684ipc.c\uff0c\u5728\u65b0\u5efa\u7684\u5b50\u8fdb\u7a0b\u4e2d\u8c03\u7528\u7684shell\u4e2d\u6267\u884cipcs -q\u67e5\u770bmessage queue\u3002<\/p>\n<pre>root@local:~# gcc -Wall ipc.c -o ipc.o &amp;&amp; .\/ipc.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\nroot@NewNamespace:~# ipcs -q\r\n------ Message Queues --------\r\nkey   msqid   owner   perms   used-bytes   messages\r\nroot@NewNamespace:~# exit\r\nexit\r\n\u5df2\u9000\u51fa<\/pre>\n<p>\u4e0a\u9762\u7684\u7ed3\u679c\u663e\u793a\u4e2d\u53ef\u4ee5\u53d1\u73b0\uff0c\u5df2\u7ecf\u627e\u4e0d\u5230\u539f\u5148\u58f0\u660e\u7684message queue\uff0c\u5b9e\u73b0\u4e86IPC\u7684\u9694\u79bb\u3002<\/p>\n<p>\u76ee\u524d\u4f7f\u7528IPC namespace\u673a\u5236\u7684\u7cfb\u7edf\u4e0d\u591a\uff0c\u5176\u4e2d\u6bd4\u8f83\u6709\u540d\u7684\u6709PostgreSQL\u3002Docker\u672c\u8eab\u901a\u8fc7socket\u6216tcp\u8fdb\u884c\u901a\u4fe1\u3002<\/p>\n<h2>4. PID namespace<\/h2>\n<p>PID namespace\u9694\u79bb\u975e\u5e38\u5b9e\u7528\uff0c\u5b83\u5bf9\u8fdb\u7a0bPID\u91cd\u65b0\u6807\u53f7\uff0c\u5373\u4e24\u4e2a\u4e0d\u540cnamespace\u4e0b\u7684\u8fdb\u7a0b\u53ef\u4ee5\u6709\u540c\u4e00\u4e2aPID\u3002\u6bcf\u4e2aPID namespace\u90fd\u6709\u81ea\u5df1\u7684\u8ba1\u6570\u7a0b\u5e8f\u3002\u5185\u6838\u4e3a\u6240\u6709\u7684PID namespace\u7ef4\u62a4\u4e86\u4e00\u4e2a\u6811\u72b6\u7ed3\u6784\uff0c\u6700\u9876\u5c42\u7684\u662f\u7cfb\u7edf\u521d\u59cb\u65f6\u521b\u5efa\u7684\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3aroot namespace\u3002\u4ed6\u521b\u5efa\u7684\u65b0PID namespace\u5c31\u79f0\u4e4b\u4e3achild namespace\uff08\u6811\u7684\u5b50\u8282\u70b9\uff09\uff0c\u800c\u539f\u5148\u7684PID namespace\u5c31\u662f\u65b0\u521b\u5efa\u7684PID namespace\u7684parent namespace\uff08\u6811\u7684\u7236\u8282\u70b9\uff09\u3002\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\uff0c\u4e0d\u540c\u7684PID namespaces\u4f1a\u5f62\u6210\u4e00\u4e2a\u7b49\u7ea7\u4f53\u7cfb\u3002\u6240\u5c5e\u7684\u7236\u8282\u70b9\u53ef\u4ee5\u770b\u5230\u5b50\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\uff0c\u5e76\u53ef\u4ee5\u901a\u8fc7\u4fe1\u53f7\u7b49\u65b9\u5f0f\u5bf9\u5b50\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\u4ea7\u751f\u5f71\u54cd\u3002\u53cd\u8fc7\u6765\uff0c\u5b50\u8282\u70b9\u4e0d\u80fd\u770b\u5230\u7236\u8282\u70b9PID namespace\u4e2d\u7684\u4efb\u4f55\u5185\u5bb9\u3002\u7531\u6b64\u4ea7\u751f\u5982\u4e0b\u7ed3\u8bba.<\/p>\n<ul>\n<li>\u6bcf\u4e2aPID namespace\u4e2d\u7684\u7b2c\u4e00\u4e2a\u8fdb\u7a0b\u201cPID 1\u201c\uff0c\u90fd\u4f1a\u50cf\u4f20\u7edfLinux\u4e2d\u7684init\u8fdb\u7a0b\u4e00\u6837\u62e5\u6709\u7279\u6743\uff0c\u8d77\u7279\u6b8a\u4f5c\u7528\u3002<\/li>\n<li>\u4e00\u4e2anamespace\u4e2d\u7684\u8fdb\u7a0b\uff0c\u4e0d\u53ef\u80fd\u901a\u8fc7kill\u6216ptrace\u5f71\u54cd\u7236\u8282\u70b9\u6216\u8005\u5144\u5f1f\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u7684PID\u5728\u8fd9\u4e2anamespace\u4e2d\u6ca1\u6709\u4efb\u4f55\u610f\u4e49\u3002<\/li>\n<li>\u5982\u679c\u4f60\u5728\u65b0\u7684PID namespace\u4e2d\u91cd\u65b0\u6302\u8f7d\/proc\u6587\u4ef6\u7cfb\u7edf\uff0c\u4f1a\u53d1\u73b0\u5176\u4e0b\u53ea\u663e\u793a\u540c\u5c5e\u4e00\u4e2aPID namespace\u4e2d\u7684\u5176\u4ed6\u8fdb\u7a0b\u3002<\/li>\n<li>\u5728root namespace\u4e2d\u53ef\u4ee5\u770b\u5230\u6240\u6709\u7684\u8fdb\u7a0b\uff0c\u5e76\u4e14\u9012\u5f52\u5305\u542b\u6240\u6709\u5b50\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\u3002<\/li>\n<\/ul>\n<p>\u5230\u8fd9\u91cc\uff0c\u53ef\u80fd\u4f60\u5df2\u7ecf\u8054\u60f3\u5230\u4e00\u79cd\u5728\u5916\u90e8\u76d1\u63a7Docker\u4e2d\u8fd0\u884c\u7a0b\u5e8f\u7684\u65b9\u6cd5\u4e86\uff0c\u5c31\u662f\u76d1\u63a7Docker Daemon\u6240\u5728\u7684PID namespace\u4e0b\u7684\u6240\u6709\u8fdb\u7a0b\u5373\u5176\u5b50\u8fdb\u7a0b\uff0c\u518d\u8fdb\u884c\u5220\u9009\u5373\u53ef\u3002<\/p>\n<p>\u4e0b\u9762\u6211\u4eec\u901a\u8fc7\u8fd0\u884c\u4ee3\u7801\u6765\u611f\u53d7\u4e00\u4e0bPID namespace\u7684\u9694\u79bb\u6548\u679c\u3002\u4fee\u6539\u4e0a\u6587\u7684\u4ee3\u7801\uff0c\u52a0\u5165PID namespace\u7684\u6807\u8bc6\u4f4d\uff0c\u5e76\u628a\u7a0b\u5e8f\u547d\u540d\u4e3apid.c\u3002<\/p>\n<pre>\/\/[...]\r\nint child_pid = clone(child_main, child_stack+STACK_SIZE,\r\n           CLONE_NEWPID | CLONE_NEWIPC | CLONE_NEWUTS \r\n           | SIGCHLD, NULL);\r\n\/\/[...]<\/pre>\n<p>\u7f16\u8bd1\u8fd0\u884c\u53ef\u4ee5\u770b\u5230\u5982\u4e0b\u7ed3\u679c\u3002<\/p>\n<pre>root@local:~# gcc -Wall pid.c -o pid.o &amp;&amp; .\/pid.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\nroot@NewNamespace:~# echo $$\r\n1                      &lt;&lt;--\u6ce8\u610f\u6b64\u5904\u770b\u5230shell\u7684PID\u53d8\u6210\u4e861\r\nroot@NewNamespace:~# exit\r\nexit\r\n\u5df2\u9000\u51fa<\/pre>\n<p>\u6253\u5370$$\u53ef\u4ee5\u770b\u5230shell\u7684PID\uff0c\u9000\u51fa\u540e\u5982\u679c\u518d\u6b21\u6267\u884c\u53ef\u4ee5\u770b\u5230\u6548\u679c\u5982\u4e0b\u3002<\/p>\n<pre>root@local:~# echo $$\r\n17542<\/pre>\n<p>\u5df2\u7ecf\u56de\u5230\u4e86\u6b63\u5e38\u72b6\u6001\u3002\u53ef\u80fd\u6709\u7684\u8bfb\u8005\u5728\u5b50\u8fdb\u7a0b\u7684shell\u4e2d\u6267\u884c\u4e86ps aux\/top\u4e4b\u7c7b\u7684\u547d\u4ee4\uff0c\u53d1\u73b0\u8fd8\u662f\u53ef\u4ee5\u770b\u5230\u6240\u6709\u7236\u8fdb\u7a0b\u7684PID\uff0c\u90a3\u662f\u56e0\u4e3a\u6211\u4eec\u8fd8\u6ca1\u6709\u5bf9\u6587\u4ef6\u7cfb\u7edf\u8fdb\u884c\u9694\u79bb\uff0cps\/top\u4e4b\u7c7b\u7684\u547d\u4ee4\u8c03\u7528\u7684\u662f\u771f\u5b9e\u7cfb\u7edf\u4e0b\u7684\/proc\u6587\u4ef6\u5185\u5bb9\uff0c\u770b\u5230\u7684\u81ea\u7136\u662f\u6240\u6709\u7684\u8fdb\u7a0b\u3002<\/p>\n<p>\u6b64\u5916\uff0c\u4e0e\u5176\u4ed6\u7684namespace\u4e0d\u540c\u7684\u662f\uff0c\u4e3a\u4e86\u5b9e\u73b0\u4e00\u4e2a\u7a33\u5b9a\u5b89\u5168\u7684\u5bb9\u5668\uff0cPID namespace\u8fd8\u9700\u8981\u8fdb\u884c\u4e00\u4e9b\u989d\u5916\u7684\u5de5\u4f5c\u624d\u80fd\u786e\u4fdd\u5176\u4e2d\u7684\u8fdb\u7a0b\u8fd0\u884c\u987a\u5229\u3002<\/p>\n<h3>\uff081\uff09PID namespace\u4e2d\u7684init\u8fdb\u7a0b<\/h3>\n<p>\u5f53\u6211\u4eec\u65b0\u5efa\u4e00\u4e2aPID namespace\u65f6\uff0c\u9ed8\u8ba4\u542f\u52a8\u7684\u8fdb\u7a0bPID\u4e3a1\u3002\u6211\u4eec\u77e5\u9053\uff0c\u5728\u4f20\u7edf\u7684UNIX\u7cfb\u7edf\u4e2d\uff0cPID\u4e3a1\u7684\u8fdb\u7a0b\u662finit\uff0c\u5730\u4f4d\u975e\u5e38\u7279\u6b8a\u3002\u4ed6\u4f5c\u4e3a\u6240\u6709\u8fdb\u7a0b\u7684\u7236\u8fdb\u7a0b\uff0c\u7ef4\u62a4\u4e00\u5f20\u8fdb\u7a0b\u8868\uff0c\u4e0d\u65ad\u68c0\u67e5\u8fdb\u7a0b\u7684\u72b6\u6001\uff0c\u4e00\u65e6\u6709\u67d0\u4e2a\u5b50\u8fdb\u7a0b\u56e0\u4e3a\u7a0b\u5e8f\u9519\u8bef\u6210\u4e3a\u4e86\u201c\u5b64\u513f\u201d\u8fdb\u7a0b\uff0cinit\u5c31\u4f1a\u8d1f\u8d23\u56de\u6536\u8d44\u6e90\u5e76\u7ed3\u675f\u8fd9\u4e2a\u5b50\u8fdb\u7a0b\u3002\u6240\u4ee5\u5728\u4f60\u8981\u5b9e\u73b0\u7684\u5bb9\u5668\u4e2d\uff0c\u542f\u52a8\u7684\u7b2c\u4e00\u4e2a\u8fdb\u7a0b\u4e5f\u9700\u8981\u5b9e\u73b0\u7c7b\u4f3cinit\u7684\u529f\u80fd\uff0c\u7ef4\u62a4\u6240\u6709\u540e\u7eed\u542f\u52a8\u8fdb\u7a0b\u7684\u8fd0\u884c\u72b6\u6001\u3002<\/p>\n<p>\u770b\u5230\u8fd9\u91cc\uff0c\u53ef\u80fd\u8bfb\u8005\u5df2\u7ecf\u660e\u767d\u4e86\u5185\u6838\u8bbe\u8ba1\u7684\u826f\u82e6\u7528\u5fc3\u3002PID namespace\u7ef4\u62a4\u8fd9\u6837\u4e00\u4e2a\u6811\u72b6\u7ed3\u6784\uff0c\u975e\u5e38\u6709\u5229\u4e8e\u7cfb\u7edf\u7684\u8d44\u6e90\u76d1\u63a7\u4e0e\u56de\u6536\u3002Docker\u542f\u52a8\u65f6\uff0c\u7b2c\u4e00\u4e2a\u8fdb\u7a0b\u4e5f\u662f\u8fd9\u6837\uff0c\u5b9e\u73b0\u4e86\u8fdb\u7a0b\u76d1\u63a7\u548c\u8d44\u6e90\u56de\u6536\uff0c\u5b83\u5c31\u662fdockerinit\u3002<\/p>\n<h3>\uff082\uff09\u4fe1\u53f7\u4e0einit\u8fdb\u7a0b<\/h3>\n<p>PID namespace\u4e2d\u7684init\u8fdb\u7a0b\u5982\u6b64\u7279\u6b8a\uff0c\u81ea\u7136\u5185\u6838\u4e5f\u4e3a\u4ed6\u8d4b\u4e88\u4e86\u7279\u6743\u2014\u2014\u4fe1\u53f7\u5c4f\u853d\u3002\u5982\u679cinit\u4e2d\u6ca1\u6709\u5199\u5904\u7406\u67d0\u4e2a\u4fe1\u53f7\u7684\u4ee3\u7801\u903b\u8f91\uff0c\u90a3\u4e48\u4e0einit\u5728\u540c\u4e00\u4e2aPID namespace\u4e0b\u7684\u8fdb\u7a0b\uff08\u5373\u4f7f\u6709\u8d85\u7ea7\u6743\u9650\uff09\u53d1\u9001\u7ed9\u5b83\u7684\u8be5\u4fe1\u53f7\u90fd\u4f1a\u88ab\u5c4f\u853d\u3002\u8fd9\u4e2a\u529f\u80fd\u7684\u4e3b\u8981\u4f5c\u7528\u662f\u9632\u6b62init\u8fdb\u7a0b\u88ab\u8bef\u6740\u3002<\/p>\n<p>\u90a3\u4e48\u5176\u7236\u8282\u70b9PID namespace\u4e2d\u7684\u8fdb\u7a0b\u53d1\u9001\u540c\u6837\u7684\u4fe1\u53f7\u4f1a\u88ab\u5ffd\u7565\u5417\uff1f\u7236\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\u53d1\u9001\u7684\u4fe1\u53f7\uff0c\u5982\u679c\u4e0d\u662fSIGKILL\uff08\u9500\u6bc1\u8fdb\u7a0b\uff09\u6216SIGSTOP\uff08\u6682\u505c\u8fdb\u7a0b\uff09\u4e5f\u4f1a\u88ab\u5ffd\u7565\u3002\u4f46\u5982\u679c\u53d1\u9001SIGKILL\u6216SIGSTOP\uff0c\u5b50\u8282\u70b9\u7684init\u4f1a\u5f3a\u5236\u6267\u884c\uff08\u65e0\u6cd5\u901a\u8fc7\u4ee3\u7801\u6355\u6349\u8fdb\u884c\u7279\u6b8a\u5904\u7406\uff09\uff0c\u4e5f\u5c31\u662f\u8bf4\u7236\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\u6709\u6743\u7ec8\u6b62\u5b50\u8282\u70b9\u4e2d\u7684\u8fdb\u7a0b\u3002<\/p>\n<p>\u4e00\u65e6init\u8fdb\u7a0b\u88ab\u9500\u6bc1\uff0c\u540c\u4e00PID namespace\u4e2d\u7684\u5176\u4ed6\u8fdb\u7a0b\u4e5f\u4f1a\u968f\u4e4b\u63a5\u6536\u5230SIGKILL\u4fe1\u53f7\u800c\u88ab\u9500\u6bc1\u3002\u7406\u8bba\u4e0a\uff0c\u8be5PID namespace\u81ea\u7136\u4e5f\u5c31\u4e0d\u590d\u5b58\u5728\u4e86\u3002\u4f46\u662f\u5982\u679c\/proc\/[pid]\/ns\/pid\u5904\u4e8e\u88ab\u6302\u8f7d\u6216\u8005\u6253\u5f00\u72b6\u6001\uff0cnamespace\u5c31\u4f1a\u88ab\u4fdd\u7559\u4e0b\u6765\u3002\u7136\u800c\uff0c\u4fdd\u7559\u4e0b\u6765\u7684namespace\u65e0\u6cd5\u901a\u8fc7setns()\u6216\u8005fork()\u521b\u5efa\u8fdb\u7a0b\uff0c\u6240\u4ee5\u5b9e\u9645\u4e0a\u5e76\u6ca1\u6709\u4ec0\u4e48\u4f5c\u7528\u3002<\/p>\n<p>\u6211\u4eec\u5e38\u8bf4\uff0cDocker\u4e00\u65e6\u542f\u52a8\u5c31\u6709\u8fdb\u7a0b\u5728\u8fd0\u884c\uff0c\u4e0d\u5b58\u5728\u4e0d\u5305\u542b\u4efb\u4f55\u8fdb\u7a0b\u7684Docker\uff0c\u4e5f\u5c31\u662f\u8fd9\u4e2a\u9053\u7406\u3002<\/p>\n<h3>\uff083\uff09\u6302\u8f7dproc\u6587\u4ef6\u7cfb\u7edf<\/h3>\n<p>\u524d\u6587\u4e2d\u5df2\u7ecf\u63d0\u5230\uff0c\u5982\u679c\u4f60\u5728\u65b0\u7684PID namespace\u4e2d\u4f7f\u7528ps\u547d\u4ee4\u67e5\u770b\uff0c\u770b\u5230\u7684\u8fd8\u662f\u6240\u6709\u7684\u8fdb\u7a0b\uff0c\u56e0\u4e3a\u4e0ePID\u76f4\u63a5\u76f8\u5173\u7684\/proc\u6587\u4ef6\u7cfb\u7edf\uff08procfs\uff09\u6ca1\u6709\u6302\u8f7d\u5230\u4e0e\u539f\/proc\u4e0d\u540c\u7684\u4f4d\u7f6e\u3002\u6240\u4ee5\u5982\u679c\u4f60\u53ea\u60f3\u770b\u5230PID namespace\u672c\u8eab\u5e94\u8be5\u770b\u5230\u7684\u8fdb\u7a0b\uff0c\u9700\u8981\u91cd\u65b0\u6302\u8f7d\/proc\uff0c\u547d\u4ee4\u5982\u4e0b\u3002<\/p>\n<pre>root@NewNamespace:~# mount -t proc proc \/proc\r\nroot@NewNamespace:~# ps a\r\n  PID TTY      STAT   TIME COMMAND\r\n    1 pts\/1    S      0:00 \/bin\/bash\r\n   12 pts\/1    R+     0:00 ps a<\/pre>\n<p>\u53ef\u4ee5\u770b\u5230\u5b9e\u9645\u7684PID namespace\u5c31\u53ea\u6709\u4e24\u4e2a\u8fdb\u7a0b\u5728\u8fd0\u884c\u3002<\/p>\n<p>\u6ce8\u610f\uff1a\u56e0\u4e3a\u6b64\u65f6\u6211\u4eec\u6ca1\u6709\u8fdb\u884cmount namespace\u7684\u9694\u79bb\uff0c\u6240\u4ee5\u8fd9\u4e00\u6b65\u64cd\u4f5c\u5b9e\u9645\u4e0a\u5df2\u7ecf\u5f71\u54cd\u4e86 root namespace\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u5f53\u4f60\u9000\u51fa\u65b0\u5efa\u7684PID namespace\u4ee5\u540e\u518d\u6267\u884cps a\u5c31\u4f1a\u53d1\u73b0\u51fa\u9519\uff0c\u518d\u6b21\u6267\u884cmount -t proc proc \/proc\u53ef\u4ee5\u4fee\u590d\u9519\u8bef\u3002<\/p>\n<h3>\uff084\uff09unshare()\u548csetns()<\/h3>\n<p>\u5728\u5f00\u7bc7\u6211\u4eec\u5c31\u8bb2\u5230\u4e86unshare()\u548csetns()\u8fd9\u4e24\u4e2aAPI\uff0c\u800c\u8fd9\u4e24\u4e2aAPI\u5728PID namespace\u4e2d\u4f7f\u7528\u65f6\uff0c\u4e5f\u6709\u4e00\u4e9b\u7279\u522b\u4e4b\u5904\u9700\u8981\u6ce8\u610f\u3002<\/p>\n<p>unshare()\u5141\u8bb8\u7528\u6237\u5728\u539f\u6709\u8fdb\u7a0b\u4e2d\u5efa\u7acbnamespace\u8fdb\u884c\u9694\u79bb\u3002\u4f46\u662f\u521b\u5efa\u4e86PID namespace\u540e\uff0c\u539f\u5148unshare()\u8c03\u7528\u8005\u8fdb\u7a0b\u5e76\u4e0d\u8fdb\u5165\u65b0\u7684PID namespace\uff0c\u63a5\u4e0b\u6765\u521b\u5efa\u7684\u5b50\u8fdb\u7a0b\u624d\u4f1a\u8fdb\u5165\u65b0\u7684namespace\uff0c\u8fd9\u4e2a\u5b50\u8fdb\u7a0b\u4e5f\u5c31\u968f\u4e4b\u6210\u4e3a\u65b0namespace\u4e2d\u7684init\u8fdb\u7a0b\u3002<\/p>\n<p>\u7c7b\u4f3c\u7684\uff0c\u8c03\u7528setns()\u521b\u5efa\u65b0PID namespace\u65f6\uff0c\u8c03\u7528\u8005\u8fdb\u7a0b\u4e5f\u4e0d\u8fdb\u5165\u65b0\u7684PID namespace\uff0c\u800c\u662f\u968f\u540e\u521b\u5efa\u7684\u5b50\u8fdb\u7a0b\u8fdb\u5165\u3002<\/p>\n<p>\u4e3a\u4ec0\u4e48\u521b\u5efa\u5176\u4ed6namespace\u65f6unshare()\u548csetns()\u4f1a\u76f4\u63a5\u8fdb\u5165\u65b0\u7684namespace\u800c\u552f\u72ecPID namespace\u4e0d\u662f\u5982\u6b64\u5462\uff1f\u56e0\u4e3a\u8c03\u7528getpid()\u51fd\u6570\u5f97\u5230\u7684PID\u662f\u6839\u636e\u8c03\u7528\u8005\u6240\u5728\u7684PID namespace\u800c\u51b3\u5b9a\u8fd4\u56de\u54ea\u4e2aPID\uff0c\u8fdb\u5165\u65b0\u7684PID namespace\u4f1a\u5bfc\u81f4PID\u4ea7\u751f\u53d8\u5316\u3002\u800c\u5bf9\u7528\u6237\u6001\u7684\u7a0b\u5e8f\u548c\u5e93\u51fd\u6570\u6765\u8bf4\uff0c\u4ed6\u4eec\u90fd\u8ba4\u4e3a\u8fdb\u7a0b\u7684PID\u662f\u4e00\u4e2a\u5e38\u91cf\uff0cPID\u7684\u53d8\u5316\u4f1a\u5f15\u8d77\u8fd9\u4e9b\u8fdb\u7a0b\u5954\u6e83\u3002<\/p>\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u4e00\u65e6\u7a0b\u5e8f\u8fdb\u7a0b\u521b\u5efa\u4ee5\u540e\uff0c\u90a3\u4e48\u5b83\u7684PID namespace\u7684\u5173\u7cfb\u5c31\u786e\u5b9a\u4e0b\u6765\u4e86\uff0c\u8fdb\u7a0b\u4e0d\u4f1a\u53d8\u66f4\u4ed6\u4eec\u5bf9\u5e94\u7684PID namespace\u3002<\/p>\n<h2>5. Mount namespaces<\/h2>\n<p>Mount namespace\u901a\u8fc7\u9694\u79bb\u6587\u4ef6\u7cfb\u7edf\u6302\u8f7d\u70b9\u5bf9\u9694\u79bb\u6587\u4ef6\u7cfb\u7edf\u63d0\u4f9b\u652f\u6301\uff0c\u5b83\u662f\u5386\u53f2\u4e0a\u7b2c\u4e00\u4e2aLinux namespace\uff0c\u6240\u4ee5\u5b83\u7684\u6807\u8bc6\u4f4d\u6bd4\u8f83\u7279\u6b8a\uff0c\u5c31\u662fCLONE_NEWNS\u3002\u9694\u79bb\u540e\uff0c\u4e0d\u540cmount namespace\u4e2d\u7684\u6587\u4ef6\u7ed3\u6784\u53d1\u751f\u53d8\u5316\u4e5f\u4e92\u4e0d\u5f71\u54cd\u3002\u4f60\u53ef\u4ee5\u901a\u8fc7\/proc\/[pid]\/mounts\u67e5\u770b\u5230\u6240\u6709\u6302\u8f7d\u5728\u5f53\u524dnamespace\u4e2d\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u8fd8\u53ef\u4ee5\u901a\u8fc7\/proc\/[pid]\/mountstats\u770b\u5230mount namespace\u4e2d\u6587\u4ef6\u8bbe\u5907\u7684\u7edf\u8ba1\u4fe1\u606f\uff0c\u5305\u62ec\u6302\u8f7d\u6587\u4ef6\u7684\u540d\u5b57\u3001\u6587\u4ef6\u7cfb\u7edf\u7c7b\u578b\u3001\u6302\u8f7d\u4f4d\u7f6e\u7b49\u7b49\u3002<\/p>\n<p>\u8fdb\u7a0b\u5728\u521b\u5efamount namespace\u65f6\uff0c\u4f1a\u628a\u5f53\u524d\u7684\u6587\u4ef6\u7ed3\u6784\u590d\u5236\u7ed9\u65b0\u7684namespace\u3002\u65b0namespace\u4e2d\u7684\u6240\u6709mount\u64cd\u4f5c\u90fd\u53ea\u5f71\u54cd\u81ea\u8eab\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u800c\u5bf9\u5916\u754c\u4e0d\u4f1a\u4ea7\u751f\u4efb\u4f55\u5f71\u54cd\u3002\u8fd9\u6837\u505a\u975e\u5e38\u4e25\u683c\u5730\u5b9e\u73b0\u4e86\u9694\u79bb\uff0c\u4f46\u662f\u67d0\u4e9b\u60c5\u51b5\u53ef\u80fd\u5e76\u4e0d\u9002\u7528\u3002\u6bd4\u5982\u7236\u8282\u70b9namespace\u4e2d\u7684\u8fdb\u7a0b\u6302\u8f7d\u4e86\u4e00\u5f20CD-ROM\uff0c\u8fd9\u65f6\u5b50\u8282\u70b9namespace\u62f7\u8d1d\u7684\u76ee\u5f55\u7ed3\u6784\u5c31\u65e0\u6cd5\u81ea\u52a8\u6302\u8f7d\u4e0a\u8fd9\u5f20CD-ROM\uff0c\u56e0\u4e3a\u8fd9\u79cd\u64cd\u4f5c\u4f1a\u5f71\u54cd\u5230\u7236\u8282\u70b9\u7684\u6587\u4ef6\u7cfb\u7edf\u3002<\/p>\n<p>2006 \u5e74\u5f15\u5165\u7684\u6302\u8f7d\u4f20\u64ad\uff08mount propagation\uff09\u89e3\u51b3\u4e86\u8fd9\u4e2a\u95ee\u9898\uff0c\u6302\u8f7d\u4f20\u64ad\u5b9a\u4e49\u4e86\u6302\u8f7d\u5bf9\u8c61\uff08mount object\uff09\u4e4b\u95f4\u7684\u5173\u7cfb\uff0c\u7cfb\u7edf\u7528\u8fd9\u4e9b\u5173\u7cfb\u51b3\u5b9a\u4efb\u4f55\u6302\u8f7d\u5bf9\u8c61\u4e2d\u7684\u6302\u8f7d\u4e8b\u4ef6\u5982\u4f55\u4f20\u64ad\u5230\u5176\u4ed6\u6302\u8f7d\u5bf9\u8c61\u3002\u6240\u8c13\u4f20\u64ad\u4e8b\u4ef6\uff0c\u662f\u6307\u7531\u4e00\u4e2a\u6302\u8f7d\u5bf9\u8c61\u7684\u72b6\u6001\u53d8\u5316\u5bfc\u81f4\u7684\u5176\u5b83\u6302\u8f7d\u5bf9\u8c61\u7684\u6302\u8f7d\u4e0e\u89e3\u9664\u6302\u8f7d\u52a8\u4f5c\u7684\u4e8b\u4ef6\u3002<\/p>\n<ul>\n<li>\u5171\u4eab\u5173\u7cfb\uff08share relationship\uff09\u3002\u5982\u679c\u4e24\u4e2a\u6302\u8f7d\u5bf9\u8c61\u5177\u6709\u5171\u4eab\u5173\u7cfb\uff0c\u90a3\u4e48\u4e00\u4e2a\u6302\u8f7d\u5bf9\u8c61\u4e2d\u7684\u6302\u8f7d\u4e8b\u4ef6\u4f1a\u4f20\u64ad\u5230\u53e6\u4e00\u4e2a\u6302\u8f7d\u5bf9\u8c61\uff0c\u53cd\u4e4b\u4ea6\u7136\u3002<\/li>\n<li>\u4ece\u5c5e\u5173\u7cfb\uff08slave relationship\uff09\u3002\u5982\u679c\u4e24\u4e2a\u6302\u8f7d\u5bf9\u8c61\u5f62\u6210\u4ece\u5c5e\u5173\u7cfb\uff0c\u90a3\u4e48\u4e00\u4e2a\u6302\u8f7d\u5bf9\u8c61\u4e2d\u7684\u6302\u8f7d\u4e8b\u4ef6\u4f1a\u4f20\u64ad\u5230\u53e6\u4e00\u4e2a\u6302\u8f7d\u5bf9\u8c61\uff0c\u4f46\u662f\u53cd\u8fc7\u6765\u4e0d\u884c\uff1b\u5728\u8fd9\u79cd\u5173\u7cfb\u4e2d\uff0c\u4ece\u5c5e\u5bf9\u8c61\u662f\u4e8b\u4ef6\u7684\u63a5\u6536\u8005\u3002<\/li>\n<\/ul>\n<p>\u4e00\u4e2a\u6302\u8f7d\u72b6\u6001\u53ef\u80fd\u4e3a\u5982\u4e0b\u7684\u5176\u4e2d\u4e00\u79cd\uff1a<\/p>\n<ul>\n<li>\u5171\u4eab\u6302\u8f7d\uff08shared\uff09<\/li>\n<li>\u4ece\u5c5e\u6302\u8f7d\uff08slave\uff09<\/li>\n<li>\u5171\u4eab\/\u4ece\u5c5e\u6302\u8f7d\uff08shared and slave\uff09<\/li>\n<li>\u79c1\u6709\u6302\u8f7d\uff08private\uff09<\/li>\n<li>\u4e0d\u53ef\u7ed1\u5b9a\u6302\u8f7d\uff08unbindable\uff09<\/li>\n<\/ul>\n<p>\u4f20\u64ad\u4e8b\u4ef6\u7684\u6302\u8f7d\u5bf9\u8c61\u79f0\u4e3a\u5171\u4eab\u6302\u8f7d\uff08shared mount\uff09\uff1b\u63a5\u6536\u4f20\u64ad\u4e8b\u4ef6\u7684\u6302\u8f7d\u5bf9\u8c61\u79f0\u4e3a\u4ece\u5c5e\u6302\u8f7d\uff08slave mount\uff09\u3002\u65e2\u4e0d\u4f20\u64ad\u4e5f\u4e0d\u63a5\u6536\u4f20\u64ad\u4e8b\u4ef6\u7684\u6302\u8f7d\u5bf9\u8c61\u79f0\u4e3a\u79c1\u6709\u6302\u8f7d\uff08private mount\uff09\u3002\u53e6\u4e00\u79cd\u7279\u6b8a\u7684\u6302\u8f7d\u5bf9\u8c61\u79f0\u4e3a\u4e0d\u53ef\u7ed1\u5b9a\u7684\u6302\u8f7d\uff08unbindable mount\uff09\uff0c\u5b83\u4eec\u4e0e\u79c1\u6709\u6302\u8f7d\u76f8\u4f3c\uff0c\u4f46\u662f\u4e0d\u5141\u8bb8\u6267\u884c\u7ed1\u5b9a\u6302\u8f7d\uff0c\u5373\u521b\u5efamount namespace\u65f6\u8fd9\u5757\u6587\u4ef6\u5bf9\u8c61\u4e0d\u53ef\u88ab\u590d\u5236\u3002<\/p>\n<p><a href=\"http:\/\/fwq.ai\/wp-content\/uploads\/2017\/07\/0310020.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-15472\" src=\"https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020.png\" width=\"1176\" height=\"1178\" srcset=\"https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020.png 1176w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-300x300.png 300w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-1022x1024.png 1022w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-150x150.png 150w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-768x769.png 768w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-200x200.png 200w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310020-670x671.png 670w\" sizes=\"auto, (max-width: 1176px) 100vw, 1176px\" title=\"Docker\u7684\u5185\u6838\u77e5\u8bc6\u4e4bNamespace\u8d44\u6e90\u9694\u79bb\u63d2\u56fe\" alt=\"Docker\u7684\u5185\u6838\u77e5\u8bc6\u4e4bNamespace\u8d44\u6e90\u9694\u79bb\u63d2\u56fe\" \/><\/a><\/p>\n<p>\u56fe1 mount\u5404\u7c7b\u6302\u8f7d\u72b6\u6001\u793a\u610f\u56fe<\/p>\n<p>\u5171\u4eab\u6302\u8f7d\u7684\u5e94\u7528\u573a\u666f\u975e\u5e38\u660e\u663e\uff0c\u5c31\u662f\u4e3a\u4e86\u6587\u4ef6\u6570\u636e\u7684\u5171\u4eab\u6240\u5fc5\u987b\u5b58\u5728\u7684\u4e00\u79cd\u6302\u8f7d\u65b9\u5f0f\uff1b\u4ece\u5c5e\u6302\u8f7d\u66f4\u5927\u7684\u610f\u4e49\u5728\u4e8e\u67d0\u4e9b\u201c\u53ea\u8bfb\u201d\u573a\u666f\uff1b\u79c1\u6709\u6302\u8f7d\u5176\u5b9e\u5c31\u662f\u7eaf\u7cb9\u7684\u9694\u79bb\uff0c\u4f5c\u4e3a\u4e00\u4e2a\u72ec\u7acb\u7684\u4e2a\u4f53\u800c\u5b58\u5728\uff1b\u4e0d\u53ef\u7ed1\u5b9a\u6302\u8f7d\u5219\u6709\u52a9\u4e8e\u9632\u6b62\u6ca1\u6709\u5fc5\u8981\u7684\u6587\u4ef6\u62f7\u8d1d\uff0c\u5982\u67d0\u4e2a\u7528\u6237\u6570\u636e\u76ee\u5f55\uff0c\u5f53\u6839\u76ee\u5f55\u88ab\u9012\u5f52\u5f0f\u7684\u590d\u5236\u65f6\uff0c\u7528\u6237\u76ee\u5f55\u65e0\u8bba\u4ece\u9690\u79c1\u8fd8\u662f\u5b9e\u9645\u7528\u9014\u8003\u8651\u90fd\u9700\u8981\u6709\u4e00\u4e2a\u4e0d\u53ef\u88ab\u590d\u5236\u7684\u9009\u9879\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u6240\u6709\u6302\u8f7d\u90fd\u662f\u79c1\u6709\u7684\u3002\u8bbe\u7f6e\u4e3a\u5171\u4eab\u6302\u8f7d\u7684\u547d\u4ee4\u5982\u4e0b\u3002<\/p>\n<pre>mount --make-shared &lt;mount-object&gt;<\/pre>\n<p>\u4ece\u5171\u4eab\u6302\u8f7d\u514b\u9686\u7684\u6302\u8f7d\u5bf9\u8c61\u4e5f\u662f\u5171\u4eab\u7684\u6302\u8f7d\uff1b\u5b83\u4eec\u76f8\u4e92\u4f20\u64ad\u6302\u8f7d\u4e8b\u4ef6\u3002<\/p>\n<p>\u8bbe\u7f6e\u4e3a\u4ece\u5c5e\u6302\u8f7d\u7684\u547d\u4ee4\u5982\u4e0b\u3002<\/p>\n<pre>mount --make-slave &lt;shared-mount-object&gt;<\/pre>\n<p>\u4ece\u4ece\u5c5e\u6302\u8f7d\u514b\u9686\u7684\u6302\u8f7d\u5bf9\u8c61\u4e5f\u662f\u4ece\u5c5e\u7684\u6302\u8f7d\uff0c\u5b83\u4e5f\u4ece\u5c5e\u4e8e\u539f\u6765\u7684\u4ece\u5c5e\u6302\u8f7d\u7684\u4e3b\u6302\u8f7d\u5bf9\u8c61\u3002<\/p>\n<p>\u5c06\u4e00\u4e2a\u4ece\u5c5e\u6302\u8f7d\u5bf9\u8c61\u8bbe\u7f6e\u4e3a\u5171\u4eab\/\u4ece\u5c5e\u6302\u8f7d\uff0c\u53ef\u4ee5\u6267\u884c\u5982\u4e0b\u547d\u4ee4\u6216\u8005\u5c06\u5176\u79fb\u52a8\u5230\u4e00\u4e2a\u5171\u4eab\u6302\u8f7d\u5bf9\u8c61\u4e0b\u3002<\/p>\n<pre>mount --make-shared &lt;slave-mount-object&gt;<\/pre>\n<p>\u5982\u679c\u4f60\u60f3\u628a\u4fee\u6539\u8fc7\u7684\u6302\u8f7d\u5bf9\u8c61\u91cd\u65b0\u6807\u8bb0\u4e3a\u79c1\u6709\u7684\uff0c\u53ef\u4ee5\u6267\u884c\u5982\u4e0b\u547d\u4ee4\u3002<\/p>\n<pre>mount --make-private &lt;mount-object&gt;<\/pre>\n<p>\u901a\u8fc7\u6267\u884c\u4ee5\u4e0b\u547d\u4ee4\uff0c\u53ef\u4ee5\u5c06\u6302\u8f7d\u5bf9\u8c61\u6807\u8bb0\u4e3a\u4e0d\u53ef\u7ed1\u5b9a\u7684\u3002<\/p>\n<pre>mount --make-unbindable &lt;mount-object&gt;<\/pre>\n<p>\u8fd9\u4e9b\u8bbe\u7f6e\u90fd\u53ef\u4ee5\u9012\u5f52\u5f0f\u5730\u5e94\u7528\u5230\u6240\u6709\u5b50\u76ee\u5f55\u4e2d\uff0c\u5982\u679c\u8bfb\u8005\u611f\u5174\u8da3\u53ef\u4ee5\u641c\u7d22\u5230\u76f8\u5173\u7684\u547d\u4ee4\u3002<\/p>\n<p>\u5728\u4ee3\u7801\u4e2d\u5b9e\u73b0mount namespace\u9694\u79bb\u4e0e\u5176\u4ed6namespace\u7c7b\u4f3c\uff0c\u52a0\u4e0aCLONE_NEWNS\u6807\u8bc6\u4f4d\u5373\u53ef\u3002\u8ba9\u6211\u4eec\u518d\u6b21\u4fee\u6539\u4ee3\u7801\uff0c\u5e76\u4e14\u53e6\u5b58\u4e3amount.c\u8fdb\u884c\u7f16\u8bd1\u8fd0\u884c\u3002<\/p>\n<pre>\/\/[...]\r\nint child_pid = clone(child_main, child_stack+STACK_SIZE,\r\n           CLONE_NEWNS | CLONE_NEWPID | CLONE_NEWIPC \r\n           | CLONE_NEWUTS | SIGCHLD, NULL);\r\n\/\/[...]<\/pre>\n<p>\u6267\u884c\u7684\u6548\u679c\u5c31\u5982\u540cPID namespace\u4e00\u8282\u4e2d\u201c\u6302\u8f7dproc\u6587\u4ef6\u7cfb\u7edf\u201d\u7684\u6267\u884c\u7ed3\u679c\uff0c\u533a\u522b\u5c31\u662f\u9000\u51famount namespace\u4ee5\u540e\uff0croot namespace\u7684\u6587\u4ef6\u7cfb\u7edf\u4e0d\u4f1a\u88ab\u7834\u574f\uff0c\u6b64\u5904\u5c31\u4e0d\u518d\u6f14\u793a\u4e86\u3002<\/p>\n<h2>6. Network namespace<\/h2>\n<p>\u901a\u8fc7\u4e0a\u8282\uff0c\u6211\u4eec\u4e86\u89e3\u4e86PID namespace\uff0c\u5f53\u6211\u4eec\u5174\u81f4\u52c3\u52c3\u5730\u5728\u65b0\u5efa\u7684namespace\u4e2d\u542f\u52a8\u4e00\u4e2a\u201cApache\u201d\u8fdb\u7a0b\u65f6\uff0c\u5374\u51fa\u73b0\u4e86\u201c80\u7aef\u53e3\u5df2\u88ab\u5360\u7528\u201d\u7684\u9519\u8bef\uff0c\u539f\u6765\u4e3b\u673a\u4e0a\u5df2\u7ecf\u8fd0\u884c\u4e86\u4e00\u4e2a\u201cApache\u201d\u8fdb\u7a0b\u3002\u600e\u4e48\u529e\uff1f\u8fd9\u5c31\u9700\u8981\u7528\u5230network namespace\u6280\u672f\u8fdb\u884c\u7f51\u7edc\u9694\u79bb\u5566\u3002<\/p>\n<p>Network namespace\u4e3b\u8981\u63d0\u4f9b\u4e86\u5173\u4e8e\u7f51\u7edc\u8d44\u6e90\u7684\u9694\u79bb\uff0c\u5305\u62ec\u7f51\u7edc\u8bbe\u5907\u3001IPv4\u548cIPv6\u534f\u8bae\u6808\u3001IP\u8def\u7531\u8868\u3001\u9632\u706b\u5899\u3001\/proc\/net\u76ee\u5f55\u3001\/sys\/class\/net\u76ee\u5f55\u3001\u7aef\u53e3\uff08socket\uff09\u7b49\u7b49\u3002\u4e00\u4e2a\u7269\u7406\u7684\u7f51\u7edc\u8bbe\u5907\u6700\u591a\u5b58\u5728\u5728\u4e00\u4e2anetwork namespace\u4e2d\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u521b\u5efaveth pair\uff08\u865a\u62df\u7f51\u7edc\u8bbe\u5907\u5bf9\uff1a\u6709\u4e24\u7aef\uff0c\u7c7b\u4f3c\u7ba1\u9053\uff0c\u5982\u679c\u6570\u636e\u4ece\u4e00\u7aef\u4f20\u5165\u53e6\u4e00\u7aef\u4e5f\u80fd\u63a5\u6536\u5230\uff0c\u53cd\u4e4b\u4ea6\u7136\uff09\u5728\u4e0d\u540c\u7684network namespace\u95f4\u521b\u5efa\u901a\u9053\uff0c\u4ee5\u6b64\u8fbe\u5230\u901a\u4fe1\u7684\u76ee\u7684\u3002<\/p>\n<p>\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u7269\u7406\u7f51\u7edc\u8bbe\u5907\u90fd\u5206\u914d\u5728\u6700\u521d\u7684root namespace\uff08\u8868\u793a\u7cfb\u7edf\u9ed8\u8ba4\u7684namespace\uff0c\u5728PID namespace\u4e2d\u5df2\u7ecf\u63d0\u53ca\uff09\u4e2d\u3002\u4f46\u662f\u5982\u679c\u4f60\u6709\u591a\u5757\u7269\u7406\u7f51\u5361\uff0c\u4e5f\u53ef\u4ee5\u628a\u5176\u4e2d\u4e00\u5757\u6216\u591a\u5757\u5206\u914d\u7ed9\u65b0\u521b\u5efa\u7684network namespace\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5f53\u65b0\u521b\u5efa\u7684network namespace\u88ab\u91ca\u653e\u65f6\uff08\u6240\u6709\u5185\u90e8\u7684\u8fdb\u7a0b\u90fd\u7ec8\u6b62\u5e76\u4e14namespace\u6587\u4ef6\u6ca1\u6709\u88ab\u6302\u8f7d\u6216\u6253\u5f00\uff09\uff0c\u5728\u8fd9\u4e2anamespace\u4e2d\u7684\u7269\u7406\u7f51\u5361\u4f1a\u8fd4\u56de\u5230root namespace\u800c\u975e\u521b\u5efa\u8be5\u8fdb\u7a0b\u7684\u7236\u8fdb\u7a0b\u6240\u5728\u7684network namespace\u3002<\/p>\n<p>\u5f53\u6211\u4eec\u8bf4\u5230network namespace\u65f6\uff0c\u5176\u5b9e\u6211\u4eec\u6307\u7684\u672a\u5fc5\u662f\u771f\u6b63\u7684\u7f51\u7edc\u9694\u79bb\uff0c\u800c\u662f\u628a\u7f51\u7edc\u72ec\u7acb\u51fa\u6765\uff0c\u7ed9\u5916\u90e8\u7528\u6237\u4e00\u79cd\u900f\u660e\u7684\u611f\u89c9\uff0c\u4eff\u4f5b\u8ddf\u53e6\u5916\u4e00\u4e2a\u7f51\u7edc\u5b9e\u4f53\u5728\u8fdb\u884c\u901a\u4fe1\u3002\u4e3a\u4e86\u8fbe\u5230\u8fd9\u4e2a\u76ee\u7684\uff0c\u5bb9\u5668\u7684\u7ecf\u5178\u505a\u6cd5\u5c31\u662f\u521b\u5efa\u4e00\u4e2aveth pair\uff0c\u4e00\u7aef\u653e\u7f6e\u5728\u65b0\u7684namespace\u4e2d\uff0c\u901a\u5e38\u547d\u540d\u4e3aeth0\uff0c\u4e00\u7aef\u653e\u5728\u539f\u5148\u7684namespace\u4e2d\u8fde\u63a5\u7269\u7406\u7f51\u7edc\u8bbe\u5907\uff0c\u518d\u901a\u8fc7\u7f51\u6865\u628a\u522b\u7684\u8bbe\u5907\u8fde\u63a5\u8fdb\u6765\u6216\u8005\u8fdb\u884c\u8def\u7531\u8f6c\u53d1\uff0c\u4ee5\u6b64\u7f51\u7edc\u5b9e\u73b0\u901a\u4fe1\u7684\u76ee\u7684\u3002<\/p>\n<p>\u4e5f\u8bb8\u6709\u8bfb\u8005\u4f1a\u597d\u5947\uff0c\u5728\u5efa\u7acb\u8d77veth pair\u4e4b\u524d\uff0c\u65b0\u65e7namespace\u8be5\u5982\u4f55\u901a\u4fe1\u5462\uff1f\u7b54\u6848\u662fpipe\uff08\u7ba1\u9053\uff09\u3002\u6211\u4eec\u4ee5Docker Daemon\u5728\u542f\u52a8\u5bb9\u5668dockerinit\u7684\u8fc7\u7a0b\u4e3a\u4f8b\u3002Docker Daemon\u5728\u5bbf\u4e3b\u673a\u4e0a\u8d1f\u8d23\u521b\u5efa\u8fd9\u4e2aveth pair\uff0c\u901a\u8fc7netlink\u8c03\u7528\uff0c\u628a\u4e00\u7aef\u7ed1\u5b9a\u5230docker0\u7f51\u6865\u4e0a\uff0c\u4e00\u7aef\u8fde\u8fdb\u65b0\u5efa\u7684network namespace\u8fdb\u7a0b\u4e2d\u3002\u5efa\u7acb\u7684\u8fc7\u7a0b\u4e2d\uff0cDocker Daemon\u548cdockerinit\u5c31\u901a\u8fc7pipe\u8fdb\u884c\u901a\u4fe1\uff0c\u5f53Docker Daemon\u5b8c\u6210veth-pair\u7684\u521b\u5efa\u4e4b\u524d\uff0cdockerinit\u5728\u7ba1\u9053\u7684\u53e6\u4e00\u7aef\u5faa\u73af\u7b49\u5f85\uff0c\u76f4\u5230\u7ba1\u9053\u53e6\u4e00\u7aef\u4f20\u6765Docker Daemon\u5173\u4e8eveth\u8bbe\u5907\u7684\u4fe1\u606f\uff0c\u5e76\u5173\u95ed\u7ba1\u9053\u3002dockerinit\u624d\u7ed3\u675f\u7b49\u5f85\u7684\u8fc7\u7a0b\uff0c\u5e76\u628a\u5b83\u7684\u201ceth0\u201d\u542f\u52a8\u8d77\u6765\u3002\u6574\u4e2a\u6548\u679c\u7c7b\u4f3c\u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<p><a href=\"http:\/\/fwq.ai\/wp-content\/uploads\/2017\/07\/0310021.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-15473\" src=\"https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021.png\" width=\"1190\" height=\"922\" srcset=\"https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021.png 1190w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021-300x232.png 300w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021-1024x793.png 1024w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021-768x595.png 768w, https:\/\/fwq.ai\/blog\/wp-content\/uploads\/2024\/11\/0310021-670x519.png 670w\" sizes=\"auto, (max-width: 1190px) 100vw, 1190px\" title=\"Docker\u7684\u5185\u6838\u77e5\u8bc6\u4e4bNamespace\u8d44\u6e90\u9694\u79bb\u63d2\u56fe1\" alt=\"Docker\u7684\u5185\u6838\u77e5\u8bc6\u4e4bNamespace\u8d44\u6e90\u9694\u79bb\u63d2\u56fe1\" \/><\/a><\/p>\n<p>\u56fe2 Docker\u7f51\u7edc\u793a\u610f\u56fe<\/p>\n<p>\u8ddf\u5176\u4ed6namespace\u7c7b\u4f3c\uff0c\u5bf9network namespace\u7684\u4f7f\u7528\u5176\u5b9e\u5c31\u662f\u5728\u521b\u5efa\u7684\u65f6\u5019\u6dfb\u52a0CLONE_NEWNET\u6807\u8bc6\u4f4d\u3002\u4e5f\u53ef\u4ee5\u901a\u8fc7\u547d\u4ee4\u884c\u5de5\u5177ip\u521b\u5efanetwork namespace\u3002\u5728\u4ee3\u7801\u4e2d\u5efa\u7acb\u548c\u6d4b\u8bd5network namespace\u8f83\u4e3a\u590d\u6742\uff0c\u6240\u4ee5\u4e0b\u6587\u4e3b\u8981\u901a\u8fc7ip\u547d\u4ee4\u76f4\u89c2\u7684\u611f\u53d7\u6574\u4e2anetwork namespace\u7f51\u7edc\u5efa\u7acb\u548c\u914d\u7f6e\u7684\u8fc7\u7a0b\u3002<\/p>\n<p>\u9996\u5148\u6211\u4eec\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a\u547d\u540d\u4e3atest_ns\u7684network namespace\u3002<\/p>\n<pre># ip netns add test_ns<\/pre>\n<p>\u5f53ip\u547d\u4ee4\u5de5\u5177\u521b\u5efa\u4e00\u4e2anetwork namespace\u65f6\uff0c\u4f1a\u9ed8\u8ba4\u521b\u5efa\u4e00\u4e2a\u56de\u73af\u8bbe\u5907\uff08loopback interface\uff1alo\uff09\uff0c\u5e76\u5728\/var\/run\/netns\u76ee\u5f55\u4e0b\u7ed1\u5b9a\u4e00\u4e2a\u6302\u8f7d\u70b9\uff0c\u8fd9\u5c31\u4fdd\u8bc1\u4e86\u5c31\u7b97network namespace\u4e2d\u6ca1\u6709\u8fdb\u7a0b\u5728\u8fd0\u884c\u4e5f\u4e0d\u4f1a\u88ab\u91ca\u653e\uff0c\u4e5f\u7ed9\u7cfb\u7edf\u7ba1\u7406\u5458\u5bf9\u65b0\u521b\u5efa\u7684network namespace\u8fdb\u884c\u914d\u7f6e\u63d0\u4f9b\u4e86\u5145\u8db3\u7684\u65f6\u95f4\u3002<\/p>\n<p>\u901a\u8fc7ip netns exec\u547d\u4ee4\u53ef\u4ee5\u5728\u65b0\u521b\u5efa\u7684network namespace\u4e0b\u8fd0\u884c\u7f51\u7edc\u7ba1\u7406\u547d\u4ee4\u3002<\/p>\n<pre># ip netns exec test_ns ip link list\r\n3: lo: &lt;LOOPBACK&gt; mtu 16436 qdisc noop state DOWN\r\n    link\/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00<\/pre>\n<p>\u4e0a\u9762\u7684\u547d\u4ee4\u4e3a\u6211\u4eec\u5c55\u793a\u4e86\u65b0\u5efa\u7684namespace\u4e0b\u53ef\u89c1\u7684\u7f51\u7edc\u94fe\u63a5\uff0c\u53ef\u4ee5\u770b\u5230\u72b6\u6001\u662fDOWN,\u9700\u8981\u518d\u901a\u8fc7\u547d\u4ee4\u53bb\u542f\u52a8\u3002\u53ef\u4ee5\u770b\u5230\uff0c\u6b64\u65f6\u6267\u884cping\u547d\u4ee4\u662f\u65e0\u6548\u7684\u3002<\/p>\n<pre># ip netns exec test_ns ping 127.0.0.1\r\nconnect: Network is unreachable<\/pre>\n<p>\u542f\u52a8\u547d\u4ee4\u5982\u4e0b\uff0c\u53ef\u4ee5\u770b\u5230\u542f\u52a8\u540e\u518d\u6d4b\u8bd5\u5c31\u53ef\u4ee5ping\u901a\u3002<\/p>\n<pre># ip netns exec test_ns ip link set dev lo up\r\n# ip netns exec test_ns ping 127.0.0.1\r\nPING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.\r\n64 bytes from 127.0.0.1: icmp_req=1 ttl=64 time=0.050 ms\r\n...<\/pre>\n<p>\u8fd9\u6837\u53ea\u662f\u542f\u52a8\u4e86\u672c\u5730\u7684\u56de\u73af\uff0c\u8981\u5b9e\u73b0\u4e0e\u5916\u90e8namespace\u8fdb\u884c\u901a\u4fe1\u8fd8\u9700\u8981\u518d\u5efa\u4e00\u4e2a\u7f51\u7edc\u8bbe\u5907\u5bf9\uff0c\u547d\u4ee4\u5982\u4e0b\u3002<\/p>\n<pre># ip link add veth0 type veth peer name veth1\r\n# ip link set veth1 netns test_ns\r\n# ip netns exec test_ns ifconfig veth1 10.1.1.1\/24 up\r\n# ifconfig veth0 10.1.1.2\/24 up<\/pre>\n<ul>\n<li>\u7b2c\u4e00\u6761\u547d\u4ee4\u521b\u5efa\u4e86\u4e00\u4e2a\u7f51\u7edc\u8bbe\u5907\u5bf9\uff0c\u6240\u6709\u53d1\u9001\u5230veth0\u7684\u5305veth1\u4e5f\u80fd\u63a5\u6536\u5230\uff0c\u53cd\u4e4b\u4ea6\u7136\u3002<\/li>\n<li>\u7b2c\u4e8c\u6761\u547d\u4ee4\u5219\u662f\u628aveth1\u8fd9\u4e00\u7aef\u5206\u914d\u5230test_ns\u8fd9\u4e2anetwork namespace\u3002<\/li>\n<li>\u7b2c\u4e09\u3001\u7b2c\u56db\u6761\u547d\u4ee4\u5206\u522b\u7ed9test_ns\u5185\u90e8\u548c\u5916\u90e8\u7684\u7f51\u7edc\u8bbe\u5907\u914d\u7f6eIP\uff0cveth1\u7684IP\u4e3a10.1.1.1\uff0cveth0\u7684IP\u4e3a10.1.1.2\u3002<\/li>\n<\/ul>\n<p>\u6b64\u65f6\u4e24\u8fb9\u5c31\u53ef\u4ee5\u4e92\u76f8\u8fde\u901a\u4e86\uff0c\u6548\u679c\u5982\u4e0b\u3002<\/p>\n<pre># ping 10.1.1.1\r\nPING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.\r\n64 bytes from 10.1.1.1: icmp_req=1 ttl=64 time=0.095 ms\r\n...\r\n# ip netns exec test_ns ping 10.1.1.2\r\nPING 10.1.1.2 (10.1.1.2) 56(84) bytes of data.\r\n64 bytes from 10.1.1.2: icmp_req=1 ttl=64 time=0.049 ms\r\n...<\/pre>\n<p>\u8bfb\u8005\u6709\u5174\u8da3\u53ef\u4ee5\u901a\u8fc7\u4e0b\u9762\u7684\u547d\u4ee4\u67e5\u770b\uff0c\u65b0\u7684test_ns\u6709\u7740\u81ea\u5df1\u72ec\u7acb\u7684\u8def\u7531\u548ciptables\u3002<\/p>\n<pre>ip netns exec test_ns route\r\nip netns exec test_ns iptables -L<\/pre>\n<p>\u8def\u7531\u8868\u4e2d\u53ea\u6709\u4e00\u6761\u901a\u541110.1.1.2\u7684\u89c4\u5219\uff0c\u6b64\u65f6\u5982\u679c\u8981\u8fde\u63a5\u5916\u7f51\u80af\u5b9a\u662f\u4e0d\u53ef\u80fd\u7684\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u5efa\u7acb\u7f51\u6865\u6216\u8005NAT\u6620\u5c04\u6765\u51b3\u5b9a\u8fd9\u4e2a\u95ee\u9898\u3002\u5982\u679c\u4f60\u5bf9\u6b64\u975e\u5e38\u611f\u5174\u8da3\uff0c\u53ef\u4ee5\u9605\u8bfbDocker\u7f51\u7edc\u76f8\u5173\u6587\u7ae0\u8fdb\u884c\u66f4\u6df1\u5165\u7684\u8bb2\u89e3\u3002<\/p>\n<p>\u505a\u5b8c\u8fd9\u4e9b\u5b9e\u9a8c\uff0c\u4f60\u8fd8\u53ef\u4ee5\u901a\u8fc7\u4e0b\u9762\u7684\u547d\u4ee4\u5220\u9664\u8fd9\u4e2anetwork namespace\u3002<\/p>\n<pre># ip netns delete netns1<\/pre>\n<p>\u8fd9\u6761\u547d\u4ee4\u4f1a\u79fb\u9664\u4e4b\u524d\u7684\u6302\u8f7d\uff0c\u4f46\u662f\u5982\u679cnamespace\u672c\u8eab\u8fd8\u6709\u8fdb\u7a0b\u8fd0\u884c\uff0cnamespace\u8fd8\u4f1a\u5b58\u5728\u4e0b\u53bb\uff0c\u76f4\u5230\u8fdb\u7a0b\u8fd0\u884c\u7ed3\u675f\u3002<\/p>\n<p>\u901a\u8fc7network namespace\u6211\u4eec\u53ef\u4ee5\u4e86\u89e3\u5230\uff0c\u5b9e\u9645\u4e0a\u5185\u6838\u521b\u5efa\u4e86network namespace\u4ee5\u540e\uff0c\u771f\u7684\u662f\u5f97\u5230\u4e86\u4e00\u4e2a\u88ab\u9694\u79bb\u7684\u7f51\u7edc\u3002\u4f46\u662f\u6211\u4eec\u5b9e\u9645\u4e0a\u9700\u8981\u7684\u4e0d\u662f\u8fd9\u79cd\u5b8c\u5168\u7684\u9694\u79bb\uff0c\u800c\u662f\u4e00\u4e2a\u5bf9\u7528\u6237\u6765\u8bf4\u900f\u660e\u72ec\u7acb\u7684\u7f51\u7edc\u5b9e\u4f53\uff0c\u6211\u4eec\u9700\u8981\u4e0e\u8fd9\u4e2a\u5b9e\u4f53\u901a\u4fe1\u3002\u6240\u4ee5Docker\u7684\u7f51\u7edc\u5728\u8d77\u6b65\u9636\u6bb5\u7ed9\u4eba\u4e00\u79cd\u975e\u5e38\u96be\u7528\u7684\u611f\u89c9\uff0c\u56e0\u4e3a\u4e00\u5207\u90fd\u8981\u81ea\u5df1\u53bb\u5b9e\u73b0\u3001\u53bb\u914d\u7f6e\u3002\u4f60\u9700\u8981\u4e00\u4e2a\u7f51\u6865\u6216\u8005NAT\u8fde\u63a5\u5e7f\u57df\u7f51\uff0c\u4f60\u9700\u8981\u914d\u7f6e\u8def\u7531\u89c4\u5219\u4e0e\u5bbf\u4e3b\u673a\u4e2d\u5176\u4ed6\u5bb9\u5668\u8fdb\u884c\u5fc5\u8981\u7684\u9694\u79bb\uff0c\u4f60\u751a\u81f3\u8fd8\u9700\u8981\u914d\u7f6e\u9632\u706b\u5899\u4ee5\u4fdd\u8bc1\u5b89\u5168\u7b49\u7b49\u3002\u6240\u5e78\u8fd9\u4e00\u5207\u5df2\u7ecf\u6709\u4e86\u8f83\u4e3a\u6210\u719f\u7684\u65b9\u6848\uff0c\u6211\u4eec\u4f1a\u5728Docker\u7f51\u7edc\u90e8\u5206\u8fdb\u884c\u8be6\u7ec6\u7684\u8bb2\u89e3\u3002<\/p>\n<h2>7. User namespaces<\/h2>\n<p>User namespace\u4e3b\u8981\u9694\u79bb\u4e86\u5b89\u5168\u76f8\u5173\u7684\u6807\u8bc6\u7b26\uff08identifiers\uff09\u548c\u5c5e\u6027\uff08attributes\uff09\uff0c\u5305\u62ec\u7528\u6237ID\u3001\u7528\u6237\u7ec4ID\u3001root\u76ee\u5f55\u3001key\uff08\u6307\u5bc6\u94a5\uff09\u4ee5\u53ca\u7279\u6b8a\u6743\u9650\u3002\u8bf4\u5f97\u901a\u4fd7\u4e00\u70b9\uff0c\u4e00\u4e2a\u666e\u901a\u7528\u6237\u7684\u8fdb\u7a0b\u901a\u8fc7clone()\u521b\u5efa\u7684\u65b0\u8fdb\u7a0b\u5728\u65b0user namespace\u4e2d\u53ef\u4ee5\u62e5\u6709\u4e0d\u540c\u7684\u7528\u6237\u548c\u7528\u6237\u7ec4\u3002\u8fd9\u610f\u5473\u7740\u4e00\u4e2a\u8fdb\u7a0b\u5728\u5bb9\u5668\u5916\u5c5e\u4e8e\u4e00\u4e2a\u6ca1\u6709\u7279\u6743\u7684\u666e\u901a\u7528\u6237\uff0c\u4f46\u662f\u4ed6\u521b\u5efa\u7684\u5bb9\u5668\u8fdb\u7a0b\u5374\u5c5e\u4e8e\u62e5\u6709\u6240\u6709\u6743\u9650\u7684\u8d85\u7ea7\u7528\u6237\uff0c\u8fd9\u4e2a\u6280\u672f\u4e3a\u5bb9\u5668\u63d0\u4f9b\u4e86\u6781\u5927\u7684\u81ea\u7531\u3002<\/p>\n<p>User namespace\u662f\u76ee\u524d\u7684\u516d\u4e2anamespace\u4e2d\u6700\u540e\u4e00\u4e2a\u652f\u6301\u7684\uff0c\u5e76\u4e14\u76f4\u5230Linux\u5185\u68383.8\u7248\u672c\u7684\u65f6\u5019\u8fd8\u672a\u5b8c\u5168\u5b9e\u73b0\uff08\u8fd8\u6709\u90e8\u5206\u6587\u4ef6\u7cfb\u7edf\u4e0d\u652f\u6301\uff09\u3002\u56e0\u4e3auser namespace\u5b9e\u9645\u4e0a\u5e76\u4e0d\u7b97\u5b8c\u5168\u6210\u719f\uff0c\u5f88\u591a\u53d1\u884c\u7248\u62c5\u5fc3\u5b89\u5168\u95ee\u9898\uff0c\u5728\u7f16\u8bd1\u5185\u6838\u7684\u65f6\u5019\u5e76\u672a\u5f00\u542fUSER_NS\u3002\u5b9e\u9645\u4e0a\u76ee\u524dDocker\u4e5f\u8fd8\u4e0d\u652f\u6301user namespace\uff0c\u4f46\u662f\u9884\u7559\u4e86\u76f8\u5e94\u63a5\u53e3\uff0c\u76f8\u4fe1\u5728\u4e0d\u4e45\u540e\u5c31\u4f1a\u652f\u6301\u8fd9\u4e00\u7279\u6027\u3002\u6240\u4ee5\u5728\u8fdb\u884c\u63a5\u4e0b\u6765\u7684\u4ee3\u7801\u5b9e\u9a8c\u65f6\uff0c\u8bf7\u786e\u4fdd\u4f60\u7cfb\u7edf\u7684Linux\u5185\u6838\u7248\u672c\u9ad8\u4e8e3.8\u5e76\u4e14\u5185\u6838\u7f16\u8bd1\u65f6\u5f00\u542f\u4e86USER_NS\uff08\u5982\u679c\u4f60\u4e0d\u4f1a\u9009\u62e9\uff0c\u53ef\u4ee5\u4f7f\u7528Ubuntu14.04\uff09\u3002<\/p>\n<p>Linux\u4e2d\uff0c\u7279\u6743\u7528\u6237\u7684user ID\u5c31\u662f0\uff0c\u6f14\u793a\u7684\u6700\u7ec8\u6211\u4eec\u5c06\u770b\u5230user ID\u975e0\u7684\u8fdb\u7a0b\u542f\u52a8user namespace\u540euser ID\u53ef\u4ee5\u53d8\u4e3a0\u3002\u4f7f\u7528user namespace\u7684\u65b9\u6cd5\u8ddf\u522b\u7684namespace\u76f8\u540c\uff0c\u5373\u8c03\u7528clone()\u6216unshare()\u65f6\u52a0\u5165CLONE_NEWUSER\u6807\u8bc6\u4f4d\u3002\u8001\u6837\u5b50\uff0c\u4fee\u6539\u4ee3\u7801\u5e76\u53e6\u5b58\u4e3auserns.c\uff0c\u4e3a\u4e86\u770b\u5230\u7528\u6237\u6743\u9650(Capabilities)\uff0c\u53ef\u80fd\u4f60\u8fd8\u9700\u8981\u5b89\u88c5\u4e00\u4e0blibcap-dev\u5305\u3002<\/p>\n<p>\u9996\u5148\u5305\u542b\u4ee5\u4e0b\u5934\u6587\u4ef6\u4ee5\u8c03\u7528Capabilities\u5305\u3002<\/p>\n<pre>#include &lt;sys\/capability.h&gt;<\/pre>\n<p>\u5176\u6b21\u5728\u5b50\u8fdb\u7a0b\u51fd\u6570\u4e2d\u52a0\u5165geteuid()\u548cgetegid()\u5f97\u5230namespace\u5185\u90e8\u7684user ID\uff0c\u5176\u6b21\u901a\u8fc7cap_get_proc()\u5f97\u5230\u5f53\u524d\u8fdb\u7a0b\u7684\u7528\u6237\u62e5\u6709\u7684\u6743\u9650\uff0c\u5e76\u901a\u8fc7cap_to_text\uff08\uff09\u8f93\u51fa\u3002<\/p>\n<pre>int child_main(void* args) {\r\n        printf(\"\u5728\u5b50\u8fdb\u7a0b\u4e2d!\\n\");\r\n        cap_t caps;\r\n        printf(\"eUID = %ld;  eGID = %ld;  \",\r\n                        (long) geteuid(), (long) getegid());\r\n        caps = cap_get_proc();\r\n        printf(\"capabilities: %s\\n\", cap_to_text(caps, NULL));\r\n        execv(child_args[0], child_args);\r\n        return 1;\r\n}<\/pre>\n<p>\u5728\u4e3b\u51fd\u6570\u7684clone()\u8c03\u7528\u4e2d\u52a0\u5165\u6211\u4eec\u719f\u6089\u7684\u6807\u8bc6\u7b26\u3002<\/p>\n<pre>\/\/[...]\r\nint child_pid = clone(child_main, child_stack+STACK_SIZE,\r\n            CLONE_NEWUSER | SIGCHLD, NULL);\r\n\/\/[...]<\/pre>\n<p>\u81f3\u6b64\uff0c\u7b2c\u4e00\u90e8\u5206\u7684\u4ee3\u7801\u4fee\u6539\u5c31\u7ed3\u675f\u4e86\u3002\u5728\u7f16\u8bd1\u4e4b\u524d\u6211\u4eec\u5148\u67e5\u770b\u4e00\u4e0b\u5f53\u524d\u7528\u6237\u7684uid\u548cguid\uff0c\u8bf7\u6ce8\u610f\u6b64\u65f6\u6211\u4eec\u662f\u666e\u901a\u7528\u6237\u3002<\/p>\n<pre>$ id -u\r\n1000\r\n$ id -g\r\n1000<\/pre>\n<p>\u7136\u540e\u6211\u4eec\u5f00\u59cb\u7f16\u8bd1\u8fd0\u884c\uff0c\u5e76\u8fdb\u884c\u65b0\u5efa\u7684user namespace\uff0c\u4f60\u4f1a\u53d1\u73b0shell\u63d0\u793a\u7b26\u524d\u7684\u7528\u6237\u540d\u5df2\u7ecf\u53d8\u4e3anobody\u3002<\/p>\n<pre>sun@ubuntu$ gcc userns.c -Wall -lcap -o userns.o &amp;&amp; .\/userns.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\neUID = 65534;  eGID = 65534;  capabilities: = cap_chown,cap_dac_override,[...]37+ep  &lt;&lt;--\u6b64\u5904\u7701\u7565\u90e8\u5206\u8f93\u51fa\uff0c\u5df2\u62e5\u6709\u5168\u90e8\u6743\u9650\r\nnobody@ubuntu$<\/pre>\n<p>\u901a\u8fc7\u9a8c\u8bc1\u6211\u4eec\u53ef\u4ee5\u5f97\u5230\u4ee5\u4e0b\u4fe1\u606f\u3002<\/p>\n<ul>\n<li>user namespace\u88ab\u521b\u5efa\u540e\uff0c\u7b2c\u4e00\u4e2a\u8fdb\u7a0b\u88ab\u8d4b\u4e88\u4e86\u8be5namespace\u4e2d\u7684\u5168\u90e8\u6743\u9650\uff0c\u8fd9\u6837\u8fd9\u4e2ainit\u8fdb\u7a0b\u5c31\u53ef\u4ee5\u5b8c\u6210\u6240\u6709\u5fc5\u8981\u7684\u521d\u59cb\u5316\u5de5\u4f5c\uff0c\u800c\u4e0d\u4f1a\u56e0\u6743\u9650\u4e0d\u8db3\u800c\u51fa\u73b0\u9519\u8bef\u3002<\/li>\n<li>\u6211\u4eec\u770b\u5230namespace\u5185\u90e8\u770b\u5230\u7684UID\u548cGID\u5df2\u7ecf\u4e0e\u5916\u90e8\u4e0d\u540c\u4e86\uff0c\u9ed8\u8ba4\u663e\u793a\u4e3a65534\uff0c\u8868\u793a\u5c1a\u672a\u4e0e\u5916\u90e8namespace\u7528\u6237\u6620\u5c04\u3002\u6211\u4eec\u9700\u8981\u5bf9user namespace\u5185\u90e8\u7684\u8fd9\u4e2a\u521d\u59cbuser\u548c\u5176\u5916\u90e8namespace\u67d0\u4e2a\u7528\u6237\u5efa\u7acb\u6620\u5c04\uff0c\u8fd9\u6837\u53ef\u4ee5\u4fdd\u8bc1\u5f53\u6d89\u53ca\u5230\u4e00\u4e9b\u5bf9\u5916\u90e8namespace\u7684\u64cd\u4f5c\u65f6\uff0c\u7cfb\u7edf\u53ef\u4ee5\u68c0\u9a8c\u5176\u6743\u9650\uff08\u6bd4\u5982\u53d1\u9001\u4e00\u4e2a\u4fe1\u53f7\u6216\u64cd\u4f5c\u67d0\u4e2a\u6587\u4ef6\uff09\u3002\u540c\u6837\u7528\u6237\u7ec4\u4e5f\u8981\u5efa\u7acb\u6620\u5c04\u3002<\/li>\n<li>\u8fd8\u6709\u4e00\u70b9\u867d\u7136\u4e0d\u80fd\u4ece\u8f93\u51fa\u4e2d\u770b\u51fa\u6765\uff0c\u4f46\u662f\u503c\u5f97\u6ce8\u610f\u3002\u7528\u6237\u5728\u65b0namespace\u4e2d\u6709\u5168\u90e8\u6743\u9650\uff0c\u4f46\u662f\u4ed6\u5728\u521b\u5efa\u4ed6\u7684\u7236namespace\u4e2d\u4e0d\u542b\u4efb\u4f55\u6743\u9650\u3002\u5c31\u7b97\u8c03\u7528\u548c\u521b\u5efa\u4ed6\u7684\u8fdb\u7a0b\u6709\u5168\u90e8\u6743\u9650\u4e5f\u662f\u5982\u6b64\u3002\u6240\u4ee5\u54ea\u6015\u662froot\u7528\u6237\u8c03\u7528\u4e86clone()\u5728user namespace\u4e2d\u521b\u5efa\u51fa\u7684\u65b0\u7528\u6237\u5728\u5916\u90e8\u4e5f\u6ca1\u6709\u4efb\u4f55\u6743\u9650\u3002<\/li>\n<li>\u6700\u540e\uff0cuser namespace\u7684\u521b\u5efa\u5176\u5b9e\u662f\u4e00\u4e2a\u5c42\u5c42\u5d4c\u5957\u7684\u6811\u72b6\u7ed3\u6784\u3002\u6700\u4e0a\u5c42\u7684\u6839\u8282\u70b9\u5c31\u662froot namespace\uff0c\u65b0\u521b\u5efa\u7684\u6bcf\u4e2auser namespace\u90fd\u6709\u4e00\u4e2a\u7236\u8282\u70b9user namespace\u4ee5\u53ca\u96f6\u4e2a\u6216\u591a\u4e2a\u5b50\u8282\u70b9user namespace\uff0c\u8fd9\u4e00\u70b9\u4e0ePID namespace\u975e\u5e38\u76f8\u4f3c\u3002<\/li>\n<\/ul>\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u5c31\u8981\u8fdb\u884c\u7528\u6237\u7ed1\u5b9a\u64cd\u4f5c\uff0c\u901a\u8fc7\u5728\/proc\/[pid]\/uid_map\u548c\/proc\/[pid]\/gid_map\u4e24\u4e2a\u6587\u4ef6\u4e2d\u5199\u5165\u5bf9\u5e94\u7684\u7ed1\u5b9a\u4fe1\u606f\u53ef\u4ee5\u5b9e\u73b0\u8fd9\u4e00\u70b9\uff0c\u683c\u5f0f\u5982\u4e0b\u3002<\/p>\n<pre>ID-inside-ns   ID-outside-ns   length<\/pre>\n<p>\u5199\u8fd9\u4e24\u4e2a\u6587\u4ef6\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u51e0\u70b9\u3002<\/p>\n<ul>\n<li>\u8fd9\u4e24\u4e2a\u6587\u4ef6\u53ea\u5141\u8bb8\u7531\u62e5\u6709\u8be5user namespace\u4e2dCAP_SETUID\u6743\u9650\u7684\u8fdb\u7a0b\u5199\u5165\u4e00\u6b21\uff0c\u4e0d\u5141\u8bb8\u4fee\u6539\u3002<\/li>\n<li>\u5199\u5165\u7684\u8fdb\u7a0b\u5fc5\u987b\u662f\u8be5user namespace\u7684\u7236namespace\u6216\u8005\u5b50namespace\u3002<\/li>\n<li>\u7b2c\u4e00\u4e2a\u5b57\u6bb5ID-inside-ns\u8868\u793a\u65b0\u5efa\u7684user namespace\u4e2d\u5bf9\u5e94\u7684user\/group ID\uff0c\u7b2c\u4e8c\u4e2a\u5b57\u6bb5ID-outside-ns\u8868\u793anamespace\u5916\u90e8\u6620\u5c04\u7684user\/group ID\u3002\u6700\u540e\u4e00\u4e2a\u5b57\u6bb5\u8868\u793a\u6620\u5c04\u8303\u56f4\uff0c\u901a\u5e38\u586b1\uff0c\u8868\u793a\u53ea\u6620\u5c04\u4e00\u4e2a\uff0c\u5982\u679c\u586b\u5927\u4e8e1\u7684\u503c\uff0c\u5219\u6309\u987a\u5e8f\u5efa\u7acb\u4e00\u4e00\u6620\u5c04\u3002<\/li>\n<\/ul>\n<p>\u660e\u767d\u4e86\u4e0a\u8ff0\u539f\u7406\uff0c\u6211\u4eec\u518d\u6b21\u4fee\u6539\u4ee3\u7801\uff0c\u6dfb\u52a0\u8bbe\u7f6euid\u548cguid\u7684\u51fd\u6570\u3002<\/p>\n<pre>\/\/[...]\r\nvoid set_uid_map(pid_t pid, int inside_id, int outside_id, int length) {\r\n    char path[256];\r\n    sprintf(path, \"\/proc\/%d\/uid_map\", getpid());\r\n    FILE* uid_map = fopen(path, \"w\");\r\n    fprintf(uid_map, \"%d %d %d\", inside_id, outside_id, length);\r\n    fclose(uid_map);\r\n}\r\nvoid set_gid_map(pid_t pid, int inside_id, int outside_id, int length) {\r\n    char path[256];\r\n    sprintf(path, \"\/proc\/%d\/gid_map\", getpid());\r\n    FILE* gid_map = fopen(path, \"w\");\r\n    fprintf(gid_map, \"%d %d %d\", inside_id, outside_id, length);\r\n    fclose(gid_map);\r\n}\r\nint child_main(void* args) {\r\n    cap_t caps;\r\n    printf(\"\u5728\u5b50\u8fdb\u7a0b\u4e2d!\\n\");\r\n    set_uid_map(getpid(), 0, 1000, 1);\r\n    set_gid_map(getpid(), 0, 1000, 1);\r\n    printf(\"eUID = %ld;  eGID = %ld;  \",\r\n            (long) geteuid(), (long) getegid());\r\n    caps = cap_get_proc();\r\n    printf(\"capabilities: %s\\n\", cap_to_text(caps, NULL));\r\n    execv(child_args[0], child_args);\r\n    return 1;\r\n}\r\n\/\/[...]<\/pre>\n<p>\u7f16\u8bd1\u540e\u5373\u53ef\u770b\u5230user\u5df2\u7ecf\u53d8\u6210\u4e86root\u3002<\/p>\n<pre>$ gcc userns.c -Wall -lcap -o usernc.o &amp;&amp; .\/usernc.o\r\n\u7a0b\u5e8f\u5f00\u59cb:\r\n\u5728\u5b50\u8fdb\u7a0b\u4e2d!\r\neUID = 0;  eGID = 0;  capabilities: = [...],37+ep\r\nroot@ubuntu:~#<\/pre>\n<p>\u81f3\u6b64\uff0c\u4f60\u5c31\u5df2\u7ecf\u5b8c\u6210\u4e86\u7ed1\u5b9a\u7684\u5de5\u4f5c\uff0c\u53ef\u4ee5\u770b\u5230\u6f14\u793a\u5168\u7a0b\u90fd\u662f\u5728\u666e\u901a\u7528\u6237\u4e0b\u6267\u884c\u7684\u3002\u6700\u7ec8\u5b9e\u73b0\u4e86\u5728user namespace\u4e2d\u6210\u4e3a\u4e86root\u800c\u5bf9\u5e94\u5230\u5916\u9762\u7684\u662f\u4e00\u4e2auid\u4e3a1000\u7684\u666e\u901a\u7528\u6237\u3002<\/p>\n<p>\u5982\u679c\u4f60\u8981\u628auser namespace\u4e0e\u5176\u4ed6namespace\u6df7\u5408\u4f7f\u7528\uff0c\u90a3\u4e48\u4f9d\u65e7\u9700\u8981root\u6743\u9650\u3002\u89e3\u51b3\u65b9\u6848\u53ef\u4ee5\u662f\u5148\u4ee5\u666e\u901a\u7528\u6237\u8eab\u4efd\u521b\u5efauser namespace\uff0c\u7136\u540e\u5728\u65b0\u5efa\u7684namespace\u4e2d\u4f5c\u4e3aroot\u518dclone()\u8fdb\u7a0b\u52a0\u5165\u5176\u4ed6\u7c7b\u578b\u7684namespace\u9694\u79bb\u3002<\/p>\n<p>\u8bb2\u5b8c\u4e86user namespace\uff0c\u6211\u4eec\u518d\u6765\u8c08\u8c08Docker\u3002\u867d\u7136Docker\u76ee\u524d\u5c1a\u672a\u4f7f\u7528user namespace\uff0c\u4f46\u662f\u4ed6\u7528\u5230\u4e86\u6211\u4eec\u5728user namespace\u4e2d\u63d0\u53ca\u7684Capabilities\u673a\u5236\u3002\u4ece\u5185\u68382.2\u7248\u672c\u5f00\u59cb\uff0cLinux\u628a\u539f\u6765\u548c\u8d85\u7ea7\u7528\u6237\u76f8\u5173\u7684\u9ad8\u7ea7\u6743\u9650\u5212\u5206\u6210\u4e3a\u4e0d\u540c\u7684\u5355\u5143\uff0c\u79f0\u4e3aCapability\u3002\u8fd9\u6837\u7ba1\u7406\u5458\u5c31\u53ef\u4ee5\u72ec\u7acb\u5bf9\u7279\u5b9a\u7684Capability\u8fdb\u884c\u4f7f\u80fd\u6216\u7981\u6b62\u3002Docker\u867d\u7136\u6ca1\u6709\u4f7f\u7528user 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\u9700\u8981\u8bf4\u660e\u7684\u662f\uff0c\u672c\u6587\u6240\u8ba8\u8bba\u7684namespace\u5b9e\u73b0\u9488\u5bf9\u7684\u5747\u662fLinux\u5185\u68383.8\u53ca\u5176\u4ee5\u540e\u7684\u7248\u672c\u3002\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u9996\u5148\u4ecb\u7ecd\u4f7f\u7528namespace\u7684API\uff0c\u7136\u540e\u9488\u5bf9\u8fd9\u516d\u79cdnamespace\u8fdb\u884c\u9010\u4e00\u8bb2\u89e3\uff0c\u5e76\u901a\u8fc7\u7a0b\u5e8f\u8ba9\u4f60\u4eb2\u8eab\u611f\u53d7\u4e00\u4e0b\u8fd9\u4e9b\u9694\u79bb\u6548\u679c\uff08\u53c2\u8003\u81eahttp:\/\/lwn.net\/Articles\/531114\/\uff09\u3002 1. \u8c03\u7528namespace\u7684API namespace\u7684API\u5305\u62ecclone()\u3001setns()\u4ee5\u53caunshare()\uff0c\u8fd8\u6709\/proc\u4e0b\u7684\u90e8\u5206\u6587\u4ef6\u3002\u4e3a\u4e86\u786e\u5b9a\u9694\u79bb\u7684\u5230\u5e95\u662f\u54ea\u79cdnamespace\uff0c\u5728\u4f7f\u7528\u8fd9\u4e9bAPI\u65f6\uff0c\u901a\u5e38\u9700\u8981\u6307\u5b9a\u4ee5\u4e0b\u516d\u4e2a\u5e38\u6570\u7684\u4e00\u4e2a\u6216\u591a\u4e2a\uff0c\u901a\u8fc7|\uff08\u4f4d\u6216\uff09\u64cd\u4f5c\u6765\u5b9e\u73b0\u3002\u4f60\u53ef\u80fd\u5df2\u7ecf\u5728\u4e0a\u9762\u7684\u8868\u683c\u4e2d\u6ce8\u610f\u5230\uff0c\u8fd9\u516d\u4e2a\u53c2\u6570\u5206\u522b\u662fCLONE_NEWIPC\u3001CLONE_NEWNS\u3001CLONE_NEWNET\u3001CLONE_NEWPID\u3001CLONE_NEWUSER\u548cCLONE_NEWUTS\u3002 \uff081\uff09\u901a\u8fc7clone()\u521b\u5efa\u65b0\u8fdb\u7a0b\u7684\u540c\u65f6\u521b\u5efanamespace \u4f7f\u7528clone()\u6765\u521b\u5efa\u4e00\u4e2a\u72ec\u7acbnamespace\u7684\u8fdb\u7a0b\u662f\u6700\u5e38\u89c1\u505a\u6cd5\uff0c\u5b83\u7684\u8c03\u7528\u65b9\u5f0f\u5982\u4e0b\u3002 int clone(int (*child_func)(void *), void *child_stack, int flags, void *arg); clone()\u5b9e\u9645\u4e0a\u662f\u4f20\u7edfUNIX\u7cfb\u7edf\u8c03\u7528fork()\u7684\u4e00\u79cd\u66f4\u901a\u7528\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u5b83\u53ef\u4ee5\u901a\u8fc7flags\u6765\u63a7\u5236\u4f7f\u7528\u591a\u5c11\u529f\u80fd\u3002\u4e00\u5171\u6709\u4e8c\u5341\u591a\u79cdCLONE_*\u7684flag\uff08\u6807\u5fd7\u4f4d\uff09\u53c2\u6570\u7528\u6765\u63a7\u5236clone\u8fdb\u7a0b\u7684\u65b9\u65b9\u9762\u9762\uff08\u5982\u662f\u5426\u4e0e\u7236\u8fdb\u7a0b\u5171\u4eab\u865a\u62df\u5185\u5b58\u7b49\u7b49\uff09\uff0c\u4e0b\u9762\u5916\u9762\u9010\u4e00\u8bb2\u89e3clone\u51fd\u6570\u4f20\u5165\u7684\u53c2\u6570\u3002 \u53c2\u6570child_func\u4f20\u5165\u5b50\u8fdb\u7a0b\u8fd0\u884c\u7684\u7a0b\u5e8f\u4e3b\u51fd\u6570\u3002 \u53c2\u6570child_stack\u4f20\u5165\u5b50\u8fdb\u7a0b\u4f7f\u7528\u7684\u6808\u7a7a\u95f4 \u53c2\u6570flags\u8868\u793a\u4f7f\u7528\u54ea\u4e9bCLONE_*\u6807\u5fd7\u4f4d \u53c2\u6570args\u5219\u53ef\u7528\u4e8e\u4f20\u5165\u7528\u6237\u53c2\u6570 \u5728\u540e\u7eed\u7684\u5185\u5bb9\u4e2d\u5c06\u4f1a\u6709\u4f7f\u7528clone()\u7684\u5b9e\u9645\u7a0b\u5e8f\u53ef\u4f9b\u5927\u5bb6\u53c2\u8003\u3002 \uff082\uff09\u67e5\u770b\/proc\/[pid]\/ns\u6587\u4ef6 \u4ece3.8\u7248\u672c\u7684\u5185\u6838\u5f00\u59cb\uff0c\u7528\u6237\u5c31\u53ef\u4ee5\u5728\/proc\/[pid]\/ns\u6587\u4ef6\u4e0b\u770b\u5230\u6307\u5411\u4e0d\u540cnamespace\u53f7\u7684\u6587\u4ef6\uff0c\u6548\u679c\u5982\u4e0b\u6240\u793a\uff0c\u5f62\u5982[4026531839]\u8005\u5373\u4e3anamespace\u53f7\u3002 $ ls -l \/proc\/$$\/ns [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-15471","post","type-post","status-publish","format-standard","hentry","category-docker"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/15471","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=15471"}],"version-history":[{"count":1,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/15471\/revisions"}],"predecessor-version":[{"id":15474,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/15471\/revisions\/15474"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=15471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=15471"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=15471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}