静态pod 创建使用示例详解

2022-12-15 0 807

目录一.系统环境二.前言三.静态pod3.1 何为静态pod3.2 创建静态pod3.2.1 使用–pod-manifest-path指定静态pod目录3.2.2 静态pod默认目录/etc/kubernetes/manifests

一.系统环境服务器版本docker软件版本Kubernetes(k8s)集群版本CPU架构CentOS Linux release 7.4.1708 (Core)Docker version 20.10.12v1.21.9x86_64

Kubernetes集群架构:k8scloude1作为master节点,k8scloude2,k8scloude3作为worker节点

服务器操作系统版本CPU架构进程功能描述k8scloude1/192.168.110.130CentOS Linux release 7.4.1708 (Core)x86_64docker,kube-apiserver,etcd,kube-scheduler,kube-controller-manager,kubelet,kube-proxy,coredns,calicok8s master节点k8scloude2/192.168.110.129CentOS Linux release 7.4.1708 (Core)x86_64docker,kubelet,kube-proxy,calicok8s worker节点k8scloude3/192.168.110.128CentOS Linux release 7.4.1708 (Core)x86_64docker,kubelet,kube-proxy,calicok8s worker节点

二.前言

本文介绍静态 Pod,静态 Pod 在指定的节点上由 kubelet 守护进程直接管理,不需要 API 服务器监管。

创建静态pod的前提是已经有一套可以正常运行的Kubernetes集群,关于Kubernetes(k8s)集群的安装部署,可以查看博客《Centos7 安装部署Kubernetes(k8s)集群》https://www.jb51.net/article/266741.htm

三.静态pod

3.1 何为静态pod

静态 Pod 在指定的节点上由 kubelet 守护进程直接管理,不需要 API 服务器监管。 与由控制面管理的 Pod(例如,Deployment) 不同;kubelet 监视每个静态 Pod(在它失败之后重新启动)。静态 Pod 始终都会绑定到特定节点的 Kubelet 上。

kubelet 会尝试通过 Kubernetes API 服务器为每个静态 Pod 自动创建一个镜像 Pod。 这意味着节点上运行的静态 Pod 对 API 服务来说是可见的,但是不能通过 API 服务器来控制。 Pod 名称将把以连字符开头的节点主机名作为后缀。

说明:如果你在运行一个 Kubernetes 集群,并且在每个节点上都运行一个静态 Pod, 就可能需要考虑使用 DaemonSet 替代这种方式。静态 Pod 的 spec 不能引用其他 API 对象 (如:ServiceAccount、 ConfigMap、 Secret 等)。

3.2 创建静态pod

静态pod的应用场景为:1.使master能正常启动 2.如果某天我们的master崩溃了,如何让别人知道我们的服务器在维护?目前该命名空间是没有pod运行的

[root@k8scloude1 pod]# kubectl get podsNo resources found in pod namespace.

静态pod的创建方法为:写一个yaml文件,然后把yaml文件放在指定目录,会自动根据yaml文件创建pod。有两种方法来指定这个目录:

–pod-manifest-path

/etc/kubernetes/manifests

3.2.1 使用–pod-manifest-path指定静态pod目录

查看kubelet的配置文件位置,可以看到kubelet的配置文件在/usr/lib/systemd/system/kubelet.service

注意:我们是在k8s集群的worker节点k8scloude2上创建静态pod的

[root@k8scloude2 ~]# systemctl status kubelet● kubelet.service – kubelet: The Kubernetes Node Agent Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled) Drop-In: /usr/lib/systemd/system/kubelet.service.d └─10-kubeadm.conf Active: active (running) since 六 2022-01-15 12:27:34 CST; 5h 30min ago Docs: https://kubernetes.io/docs/ Main PID: 947 (kubelet) Memory: 122.6M CGroup: /system.slice/kubelet.service └─947 /usr/bin/kubelet –bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf –kubeconfig=/etc/kubernetes/kubelet.conf –config=/var/lib/kubelet/config.yaml –network-plugin=cni –pod-infr…

修改kubelet的配置文件/usr/lib/systemd/system/kubelet.service,使用–pod-manifest-path=/etc/kubernetes/kubelet.d指定静态pod目录。

[root@k8scloude2 ~]# vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf #–pod-manifest-path=/etc/kubernetes/kubelet.d表示静态pod的目录为/etc/kubernetes/kubelet.d[root@k8scloude2 ~]# cat /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf# Note: This dropin only works with kubeadm and kubelet v1.11+[Service]Environment=\”KUBELET_KUBECONFIG_ARGS=–bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf –kubeconfig=/etc/kubernetes/kubelet.conf –pod-manifest-path=/etc/kubernetes/kubelet.d\”Environment=\”KUBELET_CONFIG_ARGS=–config=/var/lib/kubelet/config.yaml\”# This is a file that \”kubeadm init\” and \”kubeadm join\” generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamicallyEnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.EnvironmentFile=-/etc/sysconfig/kubeletExecStart=ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS

创建静态pod目录,并使kubelet配置文件生效

[root@k8scloude2 ~]# mkdir /etc/kubernetes/kubelet.d[root@k8scloude2 ~]# systemctl daemon-reload [root@k8scloude2 ~]# systemctl restart kubelet[root@k8scloude2 ~]# systemctl status kubelet● kubelet.service – kubelet: The Kubernetes Node Agent Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled) Drop-In: /usr/lib/systemd/system/kubelet.service.d └─10-kubeadm.conf Active: active (running) since 六 2022-01-15 18:02:15 CST; 6s ago Docs: https://kubernetes.io/docs/ Main PID: 108844 (kubelet) Memory: 30.7M CGroup: /system.slice/kubelet.service ├─108844 /usr/bin/kubelet –bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf –kubeconfig=/etc/kubernetes/kubelet.conf –pod-manifest-path=/etc/kubernetes/kubelet.d –config=/var/lib/ku… └─108999 /usr/bin/kubelet –bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf –kubeconfig=/etc/kubernetes/kubelet.conf –pod-manifest-path=/etc/kubernetes/kubelet.d –config=/var/lib/ku…

进入静态pod的目录,然后创建pod yaml文件

[root@k8scloude2 ~]# cd /etc/kubernetes/kubelet.d/[root@k8scloude2 kubelet.d]# ls[root@k8scloude2 kubelet.d]# vim pod.yaml[root@k8scloude2 kubelet.d]# cat pod.yaml apiVersion: v1kind: Podmetadata: creationTimestamp: null labels: run: pod name: podspec: containers: – image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: – name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Alwaysstatus: {}

在k8s集群的master节点上查看pod,在master上可以看到该pod,由于pod.yaml没有指定namespace,默认在default下,可以看到Pod 名称(pod-k8scloude2)是以连字符开头的节点主机名作为后缀。

[root@k8scloude1 pod]# kubectl get pods -n default -o wideNAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATESpod-k8scloude2 1/1 Running 0 109s 10.244.112.153 k8scloude2 <none> <none>

当把这个pod.yaml文件从静态pod目录移走,pod就消失了

[root@k8scloude2 kubelet.d]# mv pod.yaml ~/[root@k8scloude2 kubelet.d]# ls#当把这个yaml文件移走,pod消失[root@k8scloude1 pod]# kubectl get pods -n default -o wideNo resources found in default namespace.

现在指定静态pod的namespace为pod

[root@k8scloude2 kubelet.d]# vim pod.yaml #namespace: pod:指定pod的命名空间[root@k8scloude2 kubelet.d]# cat pod.yaml apiVersion: v1kind: Podmetadata: creationTimestamp: null labels: run: pod name: pod namespace: podspec: containers: – image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: – name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Alwaysstatus: {}[root@k8scloude2 kubelet.d]# lspod.yaml

查看pod

[root@k8scloude1 pod]# kubectl get pods -n podNAME READY STATUS RESTARTS AGEpod-k8scloude2 1/1 Running 0 6s

3.2.2 静态pod默认目录/etc/kubernetes/manifests

注意:进行这一步的时候,先还原kubelet配置文件/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf

查看配置文件,可以发现静态pod默认目录为/etc/kubernetes/manifests

[root@k8scloude2 kubelet.d]# cat /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf # Note: This dropin only works with kubeadm and kubelet v1.11+[Service]Environment=\”KUBELET_KUBECONFIG_ARGS=–bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf –kubeconfig=/etc/kubernetes/kubelet.conf\”Environment=\”KUBELET_CONFIG_ARGS=–config=/var/lib/kubelet/config.yaml\”# This is a file that \”kubeadm init\” and \”kubeadm join\” generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamicallyEnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.EnvironmentFile=-/etc/sysconfig/kubeletExecStart=ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS[root@k8scloude2 kubelet.d]# ls /var/lib/kubelet/config.yaml/var/lib/kubelet/config.yaml[root@k8scloude2 kubelet.d]# cat /var/lib/kubelet/config.yaml | grep manifeststaticPodPath: /etc/kubernetes/manifests#默认的静态pod的目录为 ls /etc/kubernetes/manifests[root@k8scloude2 kubelet.d]# ls /etc/kubernetes/manifests

在默认的静态pod目录/etc/kubernetes/manifests/下创建pod yaml文件

#namespace: pod:指定pod的命名空间[root@k8scloude2 kubelet.d]# vim ~/pod.yaml [root@k8scloude2 kubelet.d]# cat ~/pod.yaml apiVersion: v1kind: Podmetadata: creationTimestamp: null labels: run: pod name: pod namespace: podspec: containers: – image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: – name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Alwaysstatus: {}[root@k8scloude2 kubelet.d]# cp ~/pod.yaml /etc/kubernetes/manifests/

可以发现,静态pod已经创建了

[root@k8scloude1 pod]# kubectl get pods -n podNAME READY STATUS RESTARTS AGEpod-k8scloude2 1/1 Running 0 6s

删除yaml文件,静态pod消失

#删除yaml文件[root@k8scloude2 kubelet.d]# rm -rf /etc/kubernetes/manifests/pod.yaml #pod消失[root@k8scloude1 pod]# kubectl get pods -n podNo resources found in pod namespace.

前面几步,静态pod是在k8s集群的worker节点上做的,现在在k8s集群的master节点上做。

注意:如果在/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf里添加了–pod-manifest-path=/etc/kubernetes/kubelet.d,则相应的/etc/kubernetes/manifests/下的yaml文件也要移动到/etc/kubernetes/kubelet.d目录下,不然k8s集群的master节点启动不起来。

可以看到k8s集群的master节点有很多静态pod。

[root@k8scloude1 pod]# ls /etc/kubernetes/manifests/etcd.yaml kube-apiserver.yaml kube-controller-manager.yaml kube-scheduler.yaml

以上就是静态pod 创建使用示例详解的详细内容,更多关于静态pod创建使用的资料请关注悠久资源网其它相关文章!

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