持续集成部署-k8s-命令行工具：基础命令的使用-摩杜云开发者社区

@TOC

1. 资源类型与别名

资源类型	缩写别名
`clusters`
`componentstatuses`	`cs`
`configmaps`	`cm`
`daemonsets`	`ds`
`deployments`	`deploy`
`endpoints`	`ep`
`event`	`ev`
`horizontalpodautoscalers`	`hpa`
`ingresses`	`ing`
`jobs`
`limitranges`	`limits`
`namespaces`	`ns`
`networkpolicies`
`nodes`	`no`
`statefulsets`
`persistentvolumeclaims`	`pvc`
`persistentvolumes`	`pv`
`pods`	`po`
`podsecuritypolicies`	`psp`
`podtemplates`
`replicasets`	`rs`
`replicationcontrollers`	`rc`
`resourcequotas`	`quota`
`cronjob`
`secrets`
`serviceaccount`	`sa`
`services`	`svc`
`storageclasses`
`thirdpartyresources`

2. 资源操作

其中关于 kubectl 的命令，不同 k8s 版本，可能会存在命令被废弃或者不支持的情况；

使用已被废弃的命令，k8s 会提示：Flag --record has been deprecated, --record will be removed in the future；
在旧版本上使用新版本才有的命令会提示：

Error: unknown flag: --include-uninitialized
See 'kubectl get --help' for usage.

2.1 创建对象

$ kubectl create -f ./my-manifest.yaml           # 创建资源
$ kubectl create -f ./my1.yaml -f ./my2.yaml     # 使用多个文件创建资源
$ kubectl create -f ./dir                        # 使用目录下的所有清单文件来创建资源
$ kubectl create -f https://git.io/vPieo         # 使用 url 来创建资源
$ kubectl run nginx --image=nginx                # 启动一个 nginx 实例
$ kubectl explain pods,svc                       # 获取 pod 和 svc 的文档

# 从 stdin 输入中创建多个 YAML 对象
$ cat << EOF | kubectl apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: my-namespace-1
---
apiVersion: v1
kind: Namespace
metadata:
  name: my-namespace-2
EOF

2.2 显示和查找资源

# Get commands with basic output
$ kubectl get services                          # 列出所有 namespace 中的所有 service
$ kubectl get pods --all-namespaces             # 列出所有 namespace 中的所有 pod
$ kubectl get pods -o wide                      # 列出所有 pod 并显示详细信息
$ kubectl get deployment my-dep                 # 列出指定 deployment
$ kubectl get pods --include-uninitialized      # 列出该 namespace 中的所有 pod 包括未初始化的

# 使用详细输出来描述命令
$ kubectl describe nodes my-node
$ kubectl describe pods my-pod

$ kubectl get services --sort-by=.metadata.name # List Services Sorted by Name

# 根据重启次数排序列出 pod
$ kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

# 获取所有具有 app=cassandra 的 pod 中的 version 标签
$ kubectl get pods --selector=app=cassandra rc -o \
  jsonpath='{.items[*].metadata.labels.version}'

# 获取所有节点的 ExternalIP
$ kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'

# 列出属于某个 PC 的 Pod 的名字
# “jq”命令用于转换复杂的 jsonpath，参考 https://stedolan.github.io/jq/
$ sel=${$(kubectl get rc my-rc --output=json | jq -j '.spec.selector | to_entries | .[] | "\(.key)=\(.value),"')%?}
$ echo $(kubectl get pods --selector=$sel --output=jsonpath={.items..metadata.name})

# 查看哪些节点已就绪
$ JSONPATH='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}' \
 && kubectl get nodes -o jsonpath="$JSONPATH" | grep "Ready=True"

# 列出当前 Pod 中使用的 Secret
$ kubectl get pods -o json | jq '.items[].spec.containers[].env[]?.valueFrom.secretKeyRef.name' | grep -v null | sort | uniq

2.3 更新资源

$ kubectl rolling-update frontend-v1 -f frontend-v2.json           # 滚动更新 pod frontend-v1
$ kubectl rolling-update frontend-v1 frontend-v2 --image=image:v2  # 更新资源名称并更新镜像
$ kubectl rolling-update frontend --image=image:v2                 # 更新 frontend pod 中的镜像
$ kubectl rolling-update frontend-v1 frontend-v2 --rollback        # 退出已存在的进行中的滚动更新
$ cat pod.json | kubectl replace -f -                              # 基于 stdin 输入的 JSON 替换 pod

# 强制替换，删除后重新创建资源。会导致服务中断。
$ kubectl replace --force -f ./pod.json

# 为 nginx RC 创建服务，启用本地 80 端口连接到容器上的 8000 端口
$ kubectl expose rc nginx --port=80 --target-port=8000

# 更新单容器 pod 的镜像版本（tag）到 v4
$ kubectl get pod mypod -o yaml | sed 's/\(image: myimage\):.*$/\1:v4/' | kubectl replace -f -

$ kubectl label pods my-pod new-label=awesome                      # 添加标签
$ kubectl annotate pods my-pod icon-url=http://goo.gl/XXBTWq       # 添加注解
$ kubectl autoscale deployment foo --min=2 --max=10                # 自动扩展 deployment “foo”

2.4 修补资源

$ kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}' # 部分更新节点

# 更新容器镜像； spec.containers[*].name 是必须的，因为这是合并的关键字
$ kubectl patch pod valid-pod -p '{"spec":{"containers":[{"name":"kubernetes-serve-hostname","image":"new image"}]}}'

# 使用具有位置数组的 json 补丁更新容器镜像
$ kubectl patch pod valid-pod --type='json' -p='[{"op": "replace", "path": "/spec/containers/0/image", "value":"new image"}]'

# 使用具有位置数组的 json 补丁禁用 deployment 的 livenessProbe
$ kubectl patch deployment valid-deployment  --type json   -p='[{"op": "remove", "path": "/spec/template/spec/containers/0/livenessProbe"}]'

2.5 编辑资源

$ kubectl edit svc/docker-registry                      # 编辑名为 docker-registry 的 service
$ KUBE_EDITOR="nano" kubectl edit svc/docker-registry   # 使用其它编辑器

2.6 scale 资源

$ kubectl scale --replicas=3 rs/foo                                 # Scale a replicaset named 'foo' to 3
$ kubectl scale --replicas=3 -f foo.yaml                            # Scale a resource specified in "foo.yaml" to 3
$ kubectl scale --current-replicas=2 --replicas=3 deployment/mysql  # If the deployment named mysql's current size is 2, scale mysql to 3
$ kubectl scale --replicas=5 rc/foo rc/bar rc/baz                   # Scale multiple replication controllers

在使用 scale 命令的时候需注意一点，scale 命令不支持对po进行操作，因为 po 属于最小的执行单元了，如果想对某个 pod 资源进行扩容，可操作 pod 对应的 deployment。

[root@docker-54 resource]# kubectl get po
NAME                                READY   STATUS    RESTARTS   AGE
httpd-deployment-59fc85cfcd-hg9p4   1/1     Running   0          6d2h
nfs-test-pd1                        1/1     Running   0          22h
nfs-test-pd2                        1/1     Running   0          22h
nginx-deployment2-dcbf9ff88-v2pzj   1/1     Running   0          6d2h
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl scale po --replicas=3 nginx-deployment2-dcbf9ff88-v2pzj   
Error from server (NotFound): the server could not find the requested resource
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get deploy
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
httpd-deployment    1/1     1            1           93d
nginx-deployment2   1/1     1            1           91d
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl scale deploy --replicas=2 nginx-deployment2
deployment.apps/nginx-deployment2 scaled
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get po
NAME                                READY   STATUS              RESTARTS   AGE
httpd-deployment-59fc85cfcd-hg9p4   1/1     Running             0          6d2h
nfs-test-pd1                        1/1     Running             0          22h
nfs-test-pd2                        1/1     Running             0          22h
nginx-deployment2-dcbf9ff88-qxtxn   0/1     ContainerCreating   0          6s
nginx-deployment2-dcbf9ff88-v2pzj   1/1     Running             0          6d2h
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get po
NAME                                READY   STATUS              RESTARTS   AGE
httpd-deployment-59fc85cfcd-hg9p4   1/1     Running             0          6d2h
nfs-test-pd1                        1/1     Running             0          22h
nfs-test-pd2                        1/1     Running             0          22h
nginx-deployment2-dcbf9ff88-qxtxn   0/1     ContainerCreating   0          11s
nginx-deployment2-dcbf9ff88-v2pzj   1/1     Running             0          6d2h
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get deploy
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
httpd-deployment    1/1     1            1           93d
nginx-deployment2   2/2     2            2           91d
[root@docker-54 resource]#

2.7 删除资源

$ kubectl delete -f ./pod.json                                              # 删除 pod.json 文件中定义的类型和名称的 pod
$ kubectl delete pod,service baz foo                                        # 删除名为“baz”的 pod 和名为“foo”的 service
$ kubectl delete pods,services -l name=myLabel                              # 删除具有 name=myLabel 标签的 pod 和 serivce
$ kubectl delete pods,services -l name=myLabel --include-uninitialized      # 删除具有 name=myLabel 标签的 pod 和 service，包括尚未初始化的
$ kubectl -n my-ns delete po,svc --all                                      # 删除 my-ns namespace 下的所有 pod 和 serivce，包括尚未初始化的

在使用过程中，如果忘记了某个命令的用法，可以使用 --help 或 -h 选项：大多数 Kubernetes 命令都支持 --help 或 -h 选项。通过在命令后面添加 --help 或 -h，您可以获取该命令的帮助信息和使用方式示例。例如：

kubectl apply --help

使用 kubectl explain 命令：kubectl explain 命令非常有用，它可以提供有关 Kubernetes API 对象和字段的详细说明。通过指定对象类型和字段名称，您可以获取关于它们的定义、类型、说明等信息；

kubectl explain pod.spec.containers

3. 格式化输出

输出 json 格式 -o json
仅打印资源名称 -o name
以纯文本格式输出所有信息 -o wide
输出 yaml 格式 -o yaml

当我们部署了某个 deployment 之后，但是我忘记了创建这个资源的 yaml 文件的位置，我想看下创建时是如何定义的，那么就可以使用格式化输出中的 yaml 格式：

[root@docker-54 resource]# kubectl get deploy
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
httpd-deployment    1/1     1            1           93d
nginx-deployment2   2/2     2            2           91d
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get deploy nginx-deployment2 -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment2","namespace":"default"},"spec":{"replicas":1,"selector":{"matchLabels":{"app":"nginx2"}},"template":{"metadata":{"labels":{"app":"nginx2"}},"spec":{"containers":[{"image":"nginx:latest","name":"nginx2","ports":[{"containerPort":80}],"resources":{"limits":{"cpu":"0.5","memory":"512Mi"}}}]}}}}
  creationTimestamp: "2023-07-04T05:50:42Z"
  generation: 2
  name: nginx-deployment2
  namespace: default
  resourceVersion: "5717734"
  uid: b47a00ed-4c34-4da2-a882-a6988f2be4cb
spec:
  progressDeadlineSeconds: 600
  replicas: 2
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: nginx2
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx2
    spec:
      containers:
      - image: nginx:latest
        imagePullPolicy: Always
        name: nginx2
        ports:
        - containerPort: 80
          protocol: TCP
        resources:
          limits:
            cpu: 500m
            memory: 512Mi
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status:
  availableReplicas: 2
  conditions:
  - lastTransitionTime: "2023-07-04T05:50:42Z"
    lastUpdateTime: "2023-07-04T05:51:15Z"
    message: ReplicaSet "nginx-deployment2-dcbf9ff88" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  - lastTransitionTime: "2023-10-03T08:55:09Z"
    lastUpdateTime: "2023-10-03T08:55:09Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  observedGeneration: 2
  readyReplicas: 2
  replicas: 2
  updatedReplicas: 2
[root@docker-54 resource]# grep -r "b47a00ed-4c34-4da2-a882-a6988f2be4cb" /etc/kubernetes/manifests/     
[root@docker-54 resource]#

这里包含了默认自定义的内容，比如 metadata.uid、status 这些，在创建的时候无需指定。并且这个输出的yaml文件为当前资源的最新定义的描述。比如这里是 replicas: 2，接着修改副本数为1之后，再次执行输出：

[root@docker-54 resource]# kubectl scale  --replicas=1 deploy  nginx-deployment2     
deployment.apps/nginx-deployment2 scaled
[root@docker-54 resource]# 
[root@docker-54 resource]# kubectl get deploy nginx-deployment2 -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment2","namespace":"default"},"spec":{"replicas":1,"selector":{"matchLabels":{"app":"nginx2"}},"template":{"metadata":{"labels":{"app":"nginx2"}},"spec":{"containers":[{"image":"nginx:latest","name":"nginx2","ports":[{"containerPort":80}],"resources":{"limits":{"cpu":"0.5","memory":"512Mi"}}}]}}}}
  creationTimestamp: "2023-07-04T05:50:42Z"
  generation: 3
  name: nginx-deployment2
  namespace: default
  resourceVersion: "5721829"
  uid: b47a00ed-4c34-4da2-a882-a6988f2be4cb
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: nginx2
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx2
    spec:
      containers:
      - image: nginx:latest
        imagePullPolicy: Always
        name: nginx2
        ports:
        - containerPort: 80
          protocol: TCP
        resources:
          limits:
            cpu: 500m
            memory: 512Mi
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status:
  availableReplicas: 1
  conditions:
  - lastTransitionTime: "2023-07-04T05:50:42Z"
    lastUpdateTime: "2023-07-04T05:51:15Z"
    message: ReplicaSet "nginx-deployment2-dcbf9ff88" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  - lastTransitionTime: "2023-10-03T08:55:09Z"
    lastUpdateTime: "2023-10-03T08:55:09Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  observedGeneration: 3
  readyReplicas: 1
  replicas: 1
  updatedReplicas: 1
[root@docker-54 resource]#

最新输出结果中 replicas: 1，可见即使使用命令对原先定义好的资源进行了修改，输出的是最新的资源定义。