{"id":7399,"date":"2022-08-30T11:35:21","date_gmt":"2022-08-30T03:35:21","guid":{"rendered":"https:\/\/egonlin.com\/?p=7399"},"modified":"2022-08-30T17:18:47","modified_gmt":"2022-08-30T09:18:47","slug":"%e9%99%84%e5%bd%951%ef%bc%9a%e5%9c%a8k8s%e4%b8%ad%e9%99%90%e5%88%b6pod%e7%9a%84pid%e6%95%b0","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=7399","title":{"rendered":"\u9644\u5f551\uff1a\u5728k8s\u4e2d\u9650\u5236pod\u7684pid\u6570"},"content":{"rendered":"<h1>\u4f7f\u7528 Cgroups \u9650\u5236 Kubernetes Pod \u8fdb\u7a0b\u6570<\/h1>\n<p>Kubernetes \u91cc\u9762\u7684 Pod \u8d44\u6e90\u662f\u6700\u5c0f\u7684\u8ba1\u7b97\u5355\u5143\uff0c\u62bd\u8c61\u4e86\u4e00\u7ec4\uff08\u4e00\u4e2a\u6216\u591a\u4e2a\uff09\u5bb9\u5668\u3002\u5bb9\u5668\u4e5f\u662f Linux \u7cfb\u7edf\u4e0a\u7684\u8fdb\u7a0b\uff0c\u4f46\u57fa\u4e8e Namespace \u548c Cgroups(Control groups) \u7b49\u6280\u672f\u5b9e\u73b0\u4e86\u4e0d\u540c\u7a0b\u5ea6\u7684\u9694\u79bb\u3002 \u7b80\u5355\u6765\u8bf4 Namespace \u53ef\u4ee5\u8ba9\u6bcf\u4e2a\u8fdb\u7a0b\u6709\u72ec\u7acb\u7684 PID, IPC \u548c\u7f51\u7edc\u7a7a\u95f4\u3002Cgroups \u53ef\u4ee5\u63a7\u5236\u8fdb\u7a0b\u7684\u8d44\u6e90\u5360\u7528\uff0c\u6bd4\u5982 CPU \uff0c\u5185\u5b58\u548c\u5141\u8bb8\u7684\u6700\u5927\u8fdb\u7a0b\u6570\u7b49\u7b49\u3002<\/p>\n<p>\u4eca\u5929\u4e3b\u8981\u4ecb\u7ecd\u5982\u4f55\u901a\u8fc7 Cgroups \u91cc\u9762\u7684 pids \u63a7\u5236\u5668\u9650\u5236 Kubernetes Pod \u5bb9\u5668\u7684\u6700\u5927\u8fdb\u7a0b\u6570\u91cf\u3002<\/p>\n<h2>\u573a\u666f\u4ecb\u7ecd<\/h2>\n<p>\u4e4b\u524d\u9047\u5230\u8fc7\u8fd9\u6837\u4e00\u4e2a\u95ee\u9898\uff0c\u6211\u4eec\u7684\u670d\u52a1\u4f1a\u8c03\u7528\u6267\u884c\u5916\u90e8\u7684\u547d\u4ee4\uff0c\u6bcf\u8c03\u7528\u4e00\u6b21\u5916\u90e8\u547d\u4ee4\u5c31\u4f1a fork \u4ea7\u751f\u5b50\u8fdb\u7a0b\u3002\u4f46\u662f\u7531\u4e8e\u4ee3\u7801\u4e0a\u7684 bug \uff0c\u6ca1\u6709\u53ca\u65f6\u5bf9\u5b50\u8fdb\u7a0b\u56de\u6536\uff0c\u7136\u540e\u8fd9\u4e2a\u5bb9\u5668\u4e0d\u65ad fork \u4ea7\u751f\u5b50\u8fdb\u7a0b\uff0c\u8017\u5c3d\u4e86\u5bbf\u4e3b\u673a\u7684\u8fdb\u7a0b\u8868\u7a7a\u95f4\uff0c\u6700\u7ec8\u5bfc\u81f4\u6574\u4e2a\u7cfb\u7edf\u4e0d\u54cd\u5e94\uff0c\u5f71\u54cd\u4e86\u5176\u5b83\u7684\u670d\u52a1\u3002<\/p>\n<p>\u8fd9\u79cd\u95ee\u9898\u9664\u4e86\u8ba9\u5f00\u53d1\u4eba\u5458\u4fee\u590d bug \u5916\uff0c\u4e5f\u9700\u8981\u5728\u7cfb\u7edf\u5c42\u9762\u5bf9\u8fdb\u7a0b\u6570\u91cf\u8fdb\u884c\u9650\u5236\u3002\u6240\u4ee5\uff0c\u5982\u679c\u4e00\u4e2a\u5bb9\u5668\u91cc\u9762\u8fd0\u884c\u7684\u670d\u52a1\u4f1a fork \u4ea7\u751f\u5b50\u8fdb\u7a0b\uff0c\u5c31\u5f88\u6709\u5fc5\u8981\u4f7f\u7528 Cgroups \u7684 pids \u63a7\u5236\u5668\u9650\u5236\u8fd9\u4e2a\u5bb9\u5668\u80fd\u8fd0\u884c\u7684\u6700\u5927\u8fdb\u7a0b\u6570\u91cf\u3002<\/p>\n<h2>\u89e3\u51b3\u65b9\u6cd5<\/h2>\n<h3>Kubelet \u5f00\u542f PodPidsLimit \u529f\u80fd<\/h3>\n<p>Kubernetes \u91cc\u9762\u7684\u6bcf\u4e2a\u8282\u70b9\u90fd\u4f1a\u8fd0\u884c\u4e00\u4e2a\u53eb\u505a Kubelet \u7684\u670d\u52a1\uff0c\u8d1f\u8d23\u8282\u70b9\u4e0a\u5bb9\u5668\u7684\u72b6\u6001\u548c\u751f\u547d\u5468\u671f\uff0c\u6bd4\u5982\u521b\u5efa\u548c\u5220\u9664\u5bb9\u5668\u3002\u6839\u636e Kubernetes \u7684\u5b98\u65b9\u6587\u6863 <a href=\"https:\/\/kubernetes.io\/docs\/concepts\/policy\/pid-limiting\/\">Process ID Limits And Reservations<\/a> \u5185\u5bb9\uff0c\u53ef\u4ee5\u8bbe\u7f6e Kubelet \u670d\u52a1\u7684 <strong>\u2013pod-max-pids<\/strong> \u914d\u7f6e\u9009\u9879\uff0c\u4e4b\u540e\u5728\u8be5\u8282\u70b9\u4e0a\u521b\u5efa\u7684\u5bb9\u5668\uff0c\u6700\u7ec8\u90fd\u4f1a\u4f7f\u7528 Cgroups pid \u63a7\u5236\u5668\u9650\u5236\u5bb9\u5668\u7684\u8fdb\u7a0b\u6570\u91cf\u3002<\/p>\n<p>\u6211\u4eec Kubernetes \u662f\u5728 CentOS 7 \u4e0a\u4f7f\u7528 kubeadm \u90e8\u7f72\u7684 v1.15.9 \u7248\u672c\uff0c\u9700\u8981\u989d\u5916\u8bbe\u7f6e <strong>SupportPodPidsLimit<\/strong> \u7684 feature-gate\uff0c\u5bf9\u5e94\u64cd\u4f5c\u5982\u4e0b\uff08\u5176\u5b83\u53d1\u884c\u7248\u5e94\u8be5\u4e5f\u7c7b\u4f3c\uff09\uff1a<\/p>\n<pre><code class=\"language-bash\"># kubelet \u4f7f\u7528 systemd \u542f\u52a8\u7684\uff0c\u53ef\u4ee5\u901a\u8fc7\u7f16\u8f91 \/etc\/sysconfig\/kubelet\n# \u6dfb\u52a0\u989d\u5916\u7684\u542f\u52a8\u53c2\u6570\uff0c\u8bbe\u7f6e pod \u6700\u5927\u8fdb\u7a0b\u6570\u4e3a 1024\n$ vim \/etc\/sysconfig\/kubelet\nKUBELET_EXTRA_ARGS=&quot;--pod-max-pids=1024 --feature-gates=\\&quot;SupportPodPidsLimit=true\\&quot;&quot;\n\n# \u91cd\u542f kubelet \u670d\u52a1\n$ systemctl restart kubelet\n\n# \u67e5\u770b\u53c2\u6570\u662f\u5426\u751f\u6548\n$ ps faux | grep kubelet | grep pod-max-pids\nroot     104865 10.5  0.6 1731392 107368 ?      Ssl  11:56   0:30 \/usr\/bin\/kubelet ... --pod-max-pids=10 --feature-gates=SupportPodPidsLimit=true<\/code><\/pre>\n<h3>\u9a8c\u8bc1 PodPidsLimit<\/h3>\n<p>\u901a\u8fc7\u914d\u7f6e Kubelet \u7684 <strong>\u2013pod-max-pids=1024<\/strong> \u9009\u9879\uff0c\u9650\u5236\u4e86\u4e00\u4e2a\u5bb9\u5668\u5185\u5141\u8bb8\u7684\u6700\u5927\u8fdb\u7a0b\u6570\u4e3a 1024 \u4e2a\u3002\u73b0\u5728\u6765\u6d4b\u8bd5\u4e0b\u5982\u679c\u5bb9\u5668\u5185\u4e0d\u65ad fork \u5b50\u8fdb\u7a0b\uff0c\u6570\u76ee\u5230\u8fbe 1024 \u4e2a\u65f6\u4f1a\u89e6\u53d1\u4ec0\u4e48\u884c\u4e3a\u3002<\/p>\n<p>\u53c2\u8003 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Fork_bomb\">Fork bomb<\/a> \u7684\u5185\u5bb9\uff0c\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a pod\uff0c\u4e0d\u65ad fork \u5b50\u8fdb\u7a0b\u3002<\/p>\n<pre><code class=\"language-bash\"># \u521b\u5efa\u666e\u901a\u7684 nginx pod yaml\n$ cat &lt;&lt;EOF &gt; test-nginx.yaml\napiVersion: v1\nkind: Pod\nmetadata:\n  name: test-nginx\nspec:\n  containers:\n  - name: nginx\n    image: nginx\nEOF\n\n# \u521b\u5efa\u5230 Kubernetes \u96c6\u7fa4\n$ kubectl apply -f test-nginx.yaml\n\n# \u8fdb\u5165 nginx \u5bb9\u5668\u6a21\u62df fork bomb \n$ kubectl exec -ti test-nginx bash\nroot@test-nginx:\/# bash -c &quot;fork() { fork | fork &amp;  }; fork&quot;\nenvironment: fork: retry: Resource temporarily unavailable\nenvironment: fork: retry: Resource temporarily unavailable\nenvironment: fork: retry: Resource temporarily unavailable<\/code><\/pre>\n<p>\u901a\u8fc7\u8fdb\u5165\u4e00\u4e2a nginx \u5bb9\u5668\u91cc\u9762\u4f7f\u7528 bash \u8fd0\u884c fork bomb \u547d\u4ee4\uff0c\u6211\u4eec\u4f1a\u53d1\u73b0\u5f53 fork \u7684\u5b50\u8fdb\u7a0b\u8fbe\u5230\u9650\u5236\u7684\u4e0a\u9650\u6570\u76ee\u540e\uff0c\u4f1a\u62a5 <strong>retry: Resource temporarily unavailable<\/strong> \u7684\u9519\u8bef\uff0c\u8fd9\u4e2a\u65f6\u5019\u518d\u770b\u4e0b\u5bbf\u4e3b\u673a\u7684 fork \u8fdb\u7a0b\u6570\u76ee\u3002<\/p>\n<pre><code class=\"language-bash\"># \u901a\u8fc7\u5728\u5916\u90e8\u5bbf\u4e3b\u673a\u6267\u884c\u4e0b\u9762\u7684\u547d\u4ee4\uff0c\u4f1a\u53d1\u73b0 fork \u7684\u8fdb\u7a0b\u6570\u76ee\u63a5\u8fd1 1024 \u4e2a\n$ ps faux | grep fork | wc -l\n1019<\/code><\/pre>\n<p>\u901a\u8fc7\u4ee5\u4e0a\u7684\u5b9e\u9a8c\uff0c\u53d1\u73b0\u80fd\u591f\u901a\u8fc7\u8bbe\u7f6e Kubelet \u7684 <strong>\u2013pod-max-pids<\/strong> \u9009\u9879\uff0c\u9650\u5236\u5bb9\u5668\u7c7b\u7684\u8fdb\u7a0b\u6570\uff0c\u907f\u514d\u5bb9\u5668\u8fdb\u7a0b\u6570\u4e0d\u65ad\u4e0a\u5347\u6700\u7ec8\u8017\u5c3d\u5bbf\u4e3b\u673a\u8d44\u6e90\uff0c\u62d6\u57ae\u6574\u4e2a\u5bbf\u4e3b\u673a\u7cfb\u7edf\u3002<\/p>\n<h2>\u539f\u7406\u5b9e\u73b0<\/h2>\n<p>\u901a\u8fc7\u4e4b\u524d\u63cf\u8ff0\u7684\u89e3\u51b3\u65b9\u6cd5\uff0c\u5df2\u7ecf\u80fd\u591f\u9650\u5236\u5bb9\u5668\u7684\u8fdb\u7a0b\u6570\u4e86\u3002<\/p>\n<p>\u73b0\u5728\u4ece\u4ee3\u7801\u7684\u5c42\u9762\u770b\u4e0b Kubelet \u5982\u4f55\u8bbe\u7f6e Cgroups pids \u63a7\u5236\u5668\u3002<\/p>\n<h3>Kubelet \u4ee3\u7801\u8c03\u7528<\/h3>\n<p>\u9996\u5148\u6765\u770b\u4e0b Kubelet \u4ee3\u7801\u91cc\u9762 <strong>\u2013pod-max-pids<\/strong> \u662f\u600e\u4e48\u751f\u6548\u7684\uff0cKubernetes \u7684\u7248\u672c\u4e3a v1.15.9\u3002<\/p><div id=\"rml_readmorelogin_placeholder\" style=\"position:relative;\"><div id=\"rml_fade_content\" style=\"position: absolute;\r\ntop:-10em;\r\nwidth:100%;\r\nheight:10em;\r\nbackground: -webkit-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -moz-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -o-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -ms-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\"><\/div><div class=\"wpf-controller aru_rml_from_in_post\" style=\"background-color:#eeeeee;border:5px solid #cce6ff;\" id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><h2 id=\"Header\">\u67e5\u770b\u66f4\u591a<\/h2><div id=\"Message\"><p>\u8054\u7cfb\u7ba1\u7406\u5458\u5fae\u4fe1tutu19192010\uff0c\u6ce8\u518c\u8d26\u53f7<\/p>\n<\/div><div id=\"StatusBarHeader\"><\/div><form id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><input name=\"post_id\" value=\"7399\" type=\"hidden\"\/><input name=\"_init_callback\" value=\"InitLogin\" type=\"hidden\"\/><input name=\"post_id\" value=\"7399\" type=\"hidden\"\/><input name=\"rt_ype\" value=\"1\" type=\"hidden\"\/><input name=\"nonce\" value=\"98317d395a\" type=\"hidden\"\/><input name=\"_wpnonce\" value=\"a6be45eab3\" type=\"hidden\"\/><input name=\"_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_proxy_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_view\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginView\" type=\"hidden\"\/><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\" width=\"400px\"><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Username:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"username\" value=\"\" type=\"text\"\/><\/td><\/tr><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Password:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"password\" value=\"\" type=\"password\"\/><\/td><\/tr><\/tbody><\/table><p class=\"wpf-table-placeholder submit\"><button class=\"wp_plugin_framework_ajax_button\" type=\"button\" style=\"background-color:#4D90FE;;color:#ffffff;;border:1px solid #3079ed;\" name=\"_event\" value=\"ButtonLogin\">Log in<\/button><\/p><\/td><td class=\"wpf-table-placeholder-input\"><\/td><\/tr><\/tbody><\/table><\/form><div id=\"ButtonStartRegister\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=register\">Register<\/a><\/div><div id=\"Link1\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=lostpassword\">Forgotten username or password?<\/a><\/div><div id=\"StatusBarFooter\"><\/div><\/div><\/div><div id=aru_remaining_content><\/div>","protected":false},"excerpt":{"rendered":"<p>\u4f7f\u7528 Cgroups \u9650\u5236 Kubernetes Pod \u8fdb\u7a0b\u6570 Kubernetes \u91cc\u9762\u7684 Pod \u8d44\u6e90\u662f [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[424,422],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/7399"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7399"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/7399\/revisions"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7399"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7399"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7399"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}