靜態(tài)pod 創(chuàng)建使用示例詳解
一.系統(tǒng)環(huán)境
服務器版本 | docker軟件版本 | Kubernetes(k8s)集群版本 | CPU架構 |
---|---|---|---|
CentOS Linux release 7.4.1708 (Core) | Docker version 20.10.12 | v1.21.9 | x86_64 |
Kubernetes集群架構:k8scloude1作為master節(jié)點,k8scloude2,k8scloude3作為worker節(jié)點
服務器 | 操作系統(tǒng)版本 | CPU架構 | 進程 | 功能描述 |
---|---|---|---|---|
k8scloude1/192.168.110.130 | CentOS Linux release 7.4.1708 (Core) | x86_64 | docker,kube-apiserver,etcd,kube-scheduler,kube-controller-manager,kubelet,kube-proxy,coredns,calico | k8s master節(jié)點 |
k8scloude2/192.168.110.129 | CentOS Linux release 7.4.1708 (Core) | x86_64 | docker,kubelet,kube-proxy,calico | k8s worker節(jié)點 |
k8scloude3/192.168.110.128 | CentOS Linux release 7.4.1708 (Core) | x86_64 | docker,kubelet,kube-proxy,calico | k8s worker節(jié)點 |
二.前言
本文介紹靜態(tài) Pod,靜態(tài) Pod 在指定的節(jié)點上由 kubelet 守護進程直接管理,不需要 API 服務器監(jiān)管。
創(chuàng)建靜態(tài)pod的前提是已經(jīng)有一套可以正常運行的Kubernetes集群,關于Kubernetes(k8s)集群的安裝部署,可以查看博客《Centos7 安裝部署Kubernetes(k8s)集群》http://www.dbjr.com.cn/article/266741.htm
三.靜態(tài)pod
3.1 何為靜態(tài)pod
靜態(tài) Pod 在指定的節(jié)點上由 kubelet 守護進程直接管理,不需要 API 服務器監(jiān)管。 與由控制面管理的 Pod(例如,Deployment) 不同;kubelet 監(jiān)視每個靜態(tài) Pod(在它失敗之后重新啟動)。靜態(tài) Pod 始終都會綁定到特定節(jié)點的 Kubelet 上。
kubelet 會嘗試通過 Kubernetes API 服務器為每個靜態(tài) Pod 自動創(chuàng)建一個鏡像 Pod。 這意味著節(jié)點上運行的靜態(tài) Pod 對 API 服務來說是可見的,但是不能通過 API 服務器來控制。 Pod 名稱將把以連字符開頭的節(jié)點主機名作為后綴。
說明:如果你在運行一個 Kubernetes 集群,并且在每個節(jié)點上都運行一個靜態(tài) Pod, 就可能需要考慮使用 DaemonSet 替代這種方式。靜態(tài) Pod 的 spec 不能引用其他 API 對象 (如:ServiceAccount、 ConfigMap、 Secret 等)。
3.2 創(chuàng)建靜態(tài)pod
靜態(tài)pod的應用場景為:1.使master能正常啟動 2.如果某天我們的master崩潰了,如何讓別人知道我們的服務器在維護?
目前該命名空間是沒有pod運行的
[root@k8scloude1 pod]# kubectl get pods No resources found in pod namespace.
靜態(tài)pod的創(chuàng)建方法為:寫一個yaml文件,然后把yaml文件放在指定目錄,會自動根據(jù)yaml文件創(chuàng)建pod。有兩種方法來指定這個目錄:
--pod-manifest-path
/etc/kubernetes/manifests
3.2.1 使用--pod-manifest-path指定靜態(tài)pod目錄
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:我們是在k8s集群的worker節(jié)點k8scloude2上創(chuàng)建靜態(tài)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指定靜態(tài)pod目錄。
[root@k8scloude2 ~]# vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf #--pod-manifest-path=/etc/kubernetes/kubelet.d表示靜態(tài)pod的目錄為/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 dynamically EnvironmentFile=-/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/kubelet ExecStart= ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS
創(chuàng)建靜態(tài)pod目錄,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...
進入靜態(tài)pod的目錄,然后創(chuàng)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: v1 kind: Pod metadata: creationTimestamp: null labels: run: pod name: pod spec: containers: - image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: - name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Always status: {}
在k8s集群的master節(jié)點上查看pod,在master上可以看到該pod,由于pod.yaml沒有指定namespace,默認在default下,可以看到Pod 名稱(pod-k8scloude2)是以連字符開頭的節(jié)點主機名作為后綴。
[root@k8scloude1 pod]# kubectl get pods -n default -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES pod-k8scloude2 1/1 Running 0 109s 10.244.112.153 k8scloude2 <none> <none>
當把這個pod.yaml文件從靜態(tài)pod目錄移走,pod就消失了
[root@k8scloude2 kubelet.d]# mv pod.yaml ~/ [root@k8scloude2 kubelet.d]# ls #當把這個yaml文件移走,pod消失 [root@k8scloude1 pod]# kubectl get pods -n default -o wide No resources found in default namespace.
現(xiàn)在指定靜態(tài)pod的namespace為pod
[root@k8scloude2 kubelet.d]# vim pod.yaml #namespace: pod:指定pod的命名空間 [root@k8scloude2 kubelet.d]# cat pod.yaml apiVersion: v1 kind: Pod metadata: creationTimestamp: null labels: run: pod name: pod namespace: pod spec: containers: - image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: - name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Always status: {} [root@k8scloude2 kubelet.d]# ls pod.yaml
查看pod
[root@k8scloude1 pod]# kubectl get pods -n pod NAME READY STATUS RESTARTS AGE pod-k8scloude2 1/1 Running 0 6s
3.2.2 靜態(tài)pod默認目錄/etc/kubernetes/manifests
注意:進行這一步的時候,先還原kubelet配置文件/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
查看配置文件,可以發(fā)現(xiàn)靜態(tài)pod默認目錄為/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 dynamically EnvironmentFile=-/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/kubelet ExecStart= 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 manifest staticPodPath: /etc/kubernetes/manifests #默認的靜態(tài)pod的目錄為 ls /etc/kubernetes/manifests [root@k8scloude2 kubelet.d]# ls /etc/kubernetes/manifests
在默認的靜態(tài)pod目錄/etc/kubernetes/manifests/下創(chuàng)建pod yaml文件
#namespace: pod:指定pod的命名空間 [root@k8scloude2 kubelet.d]# vim ~/pod.yaml [root@k8scloude2 kubelet.d]# cat ~/pod.yaml apiVersion: v1 kind: Pod metadata: creationTimestamp: null labels: run: pod name: pod namespace: pod spec: containers: - image: nginx imagePullPolicy: IfNotPresent name: pod resources: {} ports: - name: http containerPort: 80 protocol: TCP dnsPolicy: ClusterFirst restartPolicy: Always status: {} [root@k8scloude2 kubelet.d]# cp ~/pod.yaml /etc/kubernetes/manifests/
可以發(fā)現(xiàn),靜態(tài)pod已經(jīng)創(chuàng)建了
[root@k8scloude1 pod]# kubectl get pods -n pod NAME READY STATUS RESTARTS AGE pod-k8scloude2 1/1 Running 0 6s
刪除yaml文件,靜態(tài)pod消失
#刪除yaml文件 [root@k8scloude2 kubelet.d]# rm -rf /etc/kubernetes/manifests/pod.yaml #pod消失 [root@k8scloude1 pod]# kubectl get pods -n pod No resources found in pod namespace.
前面幾步,靜態(tài)pod是在k8s集群的worker節(jié)點上做的,現(xiàn)在在k8s集群的master節(jié)點上做。
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,則相應的/etc/kubernetes/manifests/下的yaml文件也要移動到/etc/kubernetes/kubelet.d目錄下,不然k8s集群的master節(jié)點啟動不起來。
可以看到k8s集群的master節(jié)點有很多靜態(tài)pod。
[root@k8scloude1 pod]# ls /etc/kubernetes/manifests/ etcd.yaml kube-apiserver.yaml kube-controller-manager.yaml kube-scheduler.yaml
以上就是靜態(tài)pod 創(chuàng)建使用示例詳解的詳細內(nèi)容,更多關于靜態(tài)pod創(chuàng)建使用的資料請關注腳本之家其它相關文章!
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