K8s的pod分类

在Kubernetes中，最小的管理元素不是一个个独立的容器，而是Pod,Pod是最小的，管理，创建，计划的最小单元。
pod的分类：
pod分为两类：自主式pod与控制器管理的pod

自主式pod

自主式pod总是在前台运行，同时接受k8s管理与调度，当集群当中的pod因为某种原因停止，k8s会根据其副本的数量，重新的生成对应的pod

​ 自我管理的pod，创建以后仍然需要提交给apiserver，由apiserver接收以后借助于调度器将其调度至指定的node节点，由node启动此pod
​ 如果此pod出现故障,需要重启容器则由kubelet来完成
​ 如果node节点故障了，那么此pod将会消失。其无法实现全局调度。所以不推荐使用此种pod

控制器管理的pod

常见的pod控制器：
ReplicationController：当启动一个pod时。这个pod如果不够用可以再启个副本，而后由控制器来管理同一类pod的各种副本与对象。一旦副本少了就会自动增加。采取多退少补的规则，精确符合我们所定义的期望。支持滚动更新

​ ReplicaSet：由一个名叫Deployment的声明式更新的控制器来管理

​ Deployment：Deployment只能管理无状态的应用

​ StateFulSet：有状态副本集，可以管理有状态的应用

​ DaemonSet：如果需要在每个node上运行一个副本的时候可以用DaemonSet

核心组键

HPA

Deployment还支持二级控制器，HPA(HorizontalPodAutoscaler，水平pod自动伸缩控制器)，一般情况下我们可以确保一个node上有2个pod在运行，万一用户访问流量增加，2个pod不足以承载这么多访问量怎么办?此时我们就应该要增加pod资源，那么到底应该加几个?

​ HPA控制器可自动监控pod、自动进行扩展。

service

假如有2个pod,pod有其生命周期,万一pod所在的节点宕机了，那么此pod将应该要在其他的节点上重建,而重建完的pod与原来的pod已经不是同一个pod了，只是两者都是运行的同一个服务而已。且每个容器都有其IP地址，重建的pod中的容器其IP地址与之前的pod中容器的IP地址是不一样的,如此一来就会存在一个问题,客户端如何访问这些pod中的容器呢?(会转换到另一个节点去运行)

​ 用于做服务发现，pod是有生命周期的，一个pod随时都有可能离去，随时都有可能会有其他内pod加进来，假如它们提供的是同一种服务，客户端是无法通过固定的手段来访问这些pod的，因为pod本身是不固定的，它们随时可能被替换掉,无论使用主机名还是IP地址，都随时会被替换掉。

​ 为了尽可能的降低客户端与pod间协调的复杂度，k8s为每一组提供同类服务的pod和其客户端之间添加了一个中间层，这个中间层是固定的,这个中间层就叫service。

​ service只要不被删除，其地址与名称皆是固定的,当客户端需要在其配置文件中写上访问某个服务时,它不再需要自动发现，只需要在配置文件中写明service的名称即可，而这个service是个调度器，其不但能够提供一个稳定的访问入口，还可以做反向代理，当service接收到客户端的请求后，会将其代理到后端的pod之上，一旦pod宕机了会立即新建一个pod，这个新建的pod会立即被service关联上，作为service后端的可用pod之一

​ 客户端程序访问服务都是通过IP+端口或者主机名+端口的方式来实现的。而service关联后端的pod不是靠它的IP和主机名，而是靠pod的标签选择器。只要创建的pod的label是统一的，无论IP地址和主机如何改变，其都能被service所识别。如此一来,只要pod属于标签选择器，只要其在service的管理范围之内，则其就会被关联到service中，当这个动态的pod关联到service中之后，再进行动态的探测此pod的IP地址、端口，再将其作为自己后端可调度的可用服务蒂王机为象。因此，客户端的请求发送到service，然后由service代理到后端真实的pod中的容器进行响应。

​ service不是一个程序，也不是一个组件，它只是一个iptables的dnat规则,service作为k8s的对象,有其自身的名称，而service的名称相当于服务的名称,而这个名称可以被解析。

AddOns附件

dns pod:装完k8s后第一件事就需要在k8s集群上部署一个dns pod，以确保各service的名称能够被解析可以动态改变，包括动态创建、动态删除、动态修改,比如把service的名称改了,dnspod会自动触发，将dns解析记录中的名称也给改掉;假如我们手动把service的ip地址给改了,改完以后会自动触发,将dns服务中的解析记录给改掉。如此一来，客户端去访问pod资源的时候可以直接访问service的名称,然后由集群中专用的dns服务来负责解析。

​ 这种pod是k8s自身的服务就需要用到的pod，所以我们把它称为基础性的系统架构级的pod对象,而且它们也被称为集群附件

kubectl命令

---

官方使用教程

create

从文件或标准输出中创建pod

# 创建一个deployment类型的pos,名字是web1，使用的镜像是nginx
[root@master ~]# kubectl create deployment web1 --image=nginx
deployment.apps/web1 created
# 查看
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
web1-5756d98cd9-fh588    1/1     Running   0          14m


# 创建deployment类型的pos,名字是nginx，使用的镜像是nginx，replicas是指定创建的个数
[root@master ~]# kubectl create deployment nginx --image=nginx --replicas=3
deployment.apps/nginx created
# 查看
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-85b98978db-9c9xs   1/1     Running   0          41s
nginx-85b98978db-fqq57   1/1     Running   0          41s
nginx-85b98978db-lfftt   1/1     Running   0          41s
web1-5756d98cd9-fh588    1/1     Running   0          9m21s


# 创建一个名为my-dep的pod，运行nginx镜像并暴露端口1111，仅仅是暴露而已
[root@master ~]# kubectl create deployment my-dep --image=nginx --port=1111
deployment.apps/my-dep created

get

显示一个或更多资源

# 查看创建的pod
[root@master ~]# kubectl get pods
NAME                    READY   STATUS    RESTARTS   AGE
web1-5756d98cd9-fh588   1/1     Running   0          2m1s

# 查看所有的service
[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        25h
my-dep       NodePort    10.97.89.122     <none>        80:32213/TCP   5m17s
nginx        ClusterIP   10.106.246.141   <none>        8000/TCP       15m

# 查看多个信息，用","隔开
[root@master ~]# kubectl get pod,svc
NAME                          READY   STATUS    RESTARTS   AGE
pod/my-dep-6fcbf46469-drs28   1/1     Running   0          36m
pod/nginx-85b98978db-9c9xs    1/1     Running   0          42m
pod/nginx-85b98978db-fqq57    1/1     Running   0          42m
pod/nginx-85b98978db-lfftt    1/1     Running   0          42m
pod/web1-5756d98cd9-fh588     1/1     Running   0          51m

NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        26h
service/my-dep       NodePort    10.97.89.122     <none>        80:32213/TCP   14m
service/nginx        ClusterIP   10.106.246.141   <none>        8000/TCP       24m


# 查看名称空间
[root@master ~]# kubectl get ns
NAME              STATUS   AGE
default           Active   25h
kube-node-lease   Active   25h
kube-public       Active   25h
kube-system       Active   25h


# 查看指定类型的pod
[root@master ~]# kubectl get deployment
NAME     READY   UP-TO-DATE   AVAILABLE   AGE
my-dep   1/1     1            1           29m
nginx    3/3     3            3           35m
web1     1/1     1            1           44m

[root@master ~]# kubectl get deployment nginx
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   3/3     3            3           35m


# 查看更详细的信息
[root@master ~]# kubectl get pod -o wide
NAME                      READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES
my-dep-6fcbf46469-drs28   1/1     Running   0          30m   10.244.2.7   node2.example.com   <none>           <none>
nginx-85b98978db-9c9xs    1/1     Running   0          36m   10.244.1.4   node1.example.com   <none>           <none>
nginx-85b98978db-fqq57    1/1     Running   0          36m   10.244.1.3   node1.example.com   <none>           <none>
nginx-85b98978db-lfftt    1/1     Running   0          36m   10.244.2.6   node2.example.com   <none>           <none>
web1-5756d98cd9-fh588     1/1     Running   0          45m   10.244.2.5   node2.example.com   <none>           <none>


# 列出一个由pod中指定的类型和名称标识的pod。json/yaml输出格式
[root@master ~]# kubectl get deployment my-dep -o json
{
    "apiVersion": "apps/v1",
    "kind": "Deployment",
    "metadata": {
        "annotations": {
            "deployment.kubernetes.io/revision": "1"
        },
        "creationTimestamp": "2021-12-19T08:52:18Z",
        "generation": 1,
        "labels": {
            "app": "my-dep"
        },
 ..................
 
 
[root@master ~]# kubectl get deployment my-dep -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
  creationTimestamp: "2021-12-19T08:52:18Z"
  generation: 1
  labels:
    app: my-dep
  name: my-dep
  namespace: default
  resourceVersion: "11093"
  uid: 8b996347-546b-4b21-80db-ebbdd65e8eb0
....................

expose

暴露一个服务的端口

# 查看正在运行的pod
[root@master ~]# kubectl get pods
NAME                      READY   STATUS    RESTARTS   AGE
my-dep-6fcbf46469-drs28   1/1     Running   0          11m
nginx-85b98978db-9c9xs    1/1     Running   0          17m
nginx-85b98978db-fqq57    1/1     Running   0          17m
nginx-85b98978db-lfftt    1/1     Running   0          17m
web1-5756d98cd9-fh588     1/1     Running   0          26m
# 暴露nginx容器里面的80端口到集群的8000端口
[root@master ~]# kubectl expose deployment nginx --port=8000 --target-port=80
service/nginx exposed
# 查看
[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP    25h
nginx        ClusterIP   10.106.246.141   <none>        8000/TCP   29s
# 访问
[root@master ~]# curl 10.106.246.141:8000
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
........


# 暴露my-dep的pod，类型为NodePort
[root@master ~]# kubectl get pods
NAME                      READY   STATUS    RESTARTS   AGE
my-dep-6fcbf46469-drs28   1/1     Running   0          20m
nginx-85b98978db-9c9xs    1/1     Running   0          27m
nginx-85b98978db-fqq57    1/1     Running   0          27m
nginx-85b98978db-lfftt    1/1     Running   0          27m
web1-5756d98cd9-fh588     1/1     Running   0          36m
# 查看
[root@master ~]# kubectl expose deployment my-dep --port 80 --type=NodePort
service/my-dep exposed
[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        25h
my-dep       NodePort    10.97.89.122     <none>        80:32213/TCP   9s
nginx        ClusterIP   10.106.246.141   <none>        8000/TCP       10m
# 访问(在浏览器访问端口32213)
[root@master ~]# curl 10.97.89.122
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>

delete

删除资源的文件名，标准输出，资源和名称，或资源和标签选择器

# 查看后删除service和pod名字叫nginx的
[root@master ~]# kubectl get svc,pods
NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        26h
service/my-dep       NodePort    10.97.89.122     <none>        80:32213/TCP   17m
service/nginx        ClusterIP   10.106.246.141   <none>        8000/TCP       28m

NAME                          READY   STATUS    RESTARTS   AGE
pod/my-dep-6fcbf46469-drs28   1/1     Running   0          39m
pod/nginx-85b98978db-9c9xs    1/1     Running   0          46m
pod/nginx-85b98978db-fqq57    1/1     Running   0          46m
pod/nginx-85b98978db-lfftt    1/1     Running   0          46m
pod/web1-5756d98cd9-fh588     1/1     Running   0          54m

[root@master ~]# kubectl delete deployment,svc nginx
deployment.apps "nginx" deleted
service "nginx" deleted

# 删除后查看
[root@master ~]# kubectl get svc,pods
NAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        26h
service/my-dep       NodePort    10.97.89.122   <none>        80:32213/TCP   18m

NAME                          READY   STATUS    RESTARTS   AGE
pod/my-dep-6fcbf46469-drs28   1/1     Running   0          40m
pod/web1-5756d98cd9-fh588     1/1     Running   0          55m

# 删除某一个类型的pod
[root@master ~]# kubectl get pod
NAME                      READY   STATUS    RESTARTS   AGE
my-dep-6fcbf46469-drs28   1/1     Running   0          42m
web1-5756d98cd9-fh588     1/1     Running   0          57m

[root@master ~]# kubectl delete deployment web1
deployment.apps "web1" deleted

[root@master ~]# kubectl get pod
NAME                      READY   STATUS    RESTARTS   AGE
my-dep-6fcbf46469-drs28   1/1     Running   0          42m

# 删除一个service
[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        26h
my-dep       NodePort    10.97.89.122   <none>        80:32213/TCP   22m

[root@master ~]# kubectl delete svc my-dep
service "my-dep" deleted

[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   26h

# 删除所有指定类型的pod
[root@master ~]# kubectl get pods
NAME                      READY   STATUS    RESTARTS   AGE
my-dep-6fcbf46469-drs28   1/1     Running   0          46m

[root@master ~]# kubectl delete deployment --all
deployment.apps "my-dep" deleted

[root@master ~]# kubectl get pods
No resources found in default namespace.

run

在集群中运行一个指定的镜像的pod(自主式pod)

# 使用run运行的pod默认为pod类型
[root@master ~]# kubectl run nginx --image nginx
pod/nginx created

[root@master ~]# kubectl get pods
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          38s

# 运行一个pod叫nginx1，使用镜像nginx，指定标签为app=nginx
[root@master ~]# kubectl run nginx1 --image=nginx --labels="app=nginx"
pod/nginx1 created

[root@master ~]# kubectl get pods
NAME     READY   STATUS    RESTARTS   AGE
nginx    1/1     Running   0          8m3s
nginx1   1/1     Running   0          66s

# 查看具体的描述
[root@master ~]# kubectl describe pod nginx1
Name:         nginx1
Namespace:    default
Priority:     0
Node:         node2.example.com/192.168.220.21
Start Time:   Sun, 19 Dec 2021 04:48:06 -0500
Labels:       app=nginx  # 标签是nginx
Annotations:  <none>
Status:       Running
IP:           10.244.2.8
.............

# 多创建几个，它们的标签都是nginx
[root@master ~]# kubectl run nginx2 --image=nginx --labels="app=nginx"
pod/nginx2 created
[root@master ~]# kubectl run nginx3 --image=nginx --labels="app=nginx"
pod/nginx3 created

# 查看
[root@master ~]# kubectl get pods
NAME     READY   STATUS    RESTARTS   AGE
nginx    1/1     Running   0          12m
nginx1   1/1     Running   0          5m41s
nginx2   1/1     Running   0          55s
nginx3   1/1     Running   0          50s

# 删除时指定标签就可以删除对应标签的pod
[root@master ~]# kubectl delete pod -l app=nginx
pod "nginx1" deleted
pod "nginx2" deleted
pod "nginx3" deleted

[root@master ~]# kubectl get pods
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          13m

# 试运行，不会真正的创建运行，可以指定在client/server端
[root@master ~]# kubectl run web --image=nginx --dry-run=client
pod/web created (dry run)

[root@master ~]# kubectl get pods
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          19m

# 启动一个pod，并将其放在前台，如果它退出，不要重新启动它
[root@master ~]# kubectl run -i -t busybox --image=busybox --restart=Never
If you don't see a command prompt, try pressing enter.
/ # ls
bin   dev   etc   home  proc  root  sys   tmp   usr   var
/ # exit
[root@master ~]# kubectl get pods
NAME      READY   STATUS      RESTARTS   AGE
busybox   0/1     Completed   0          16s
nginx     1/1     Running     0          23m

edit

使用默认编辑器编辑服务器上定义的资源

[root@master ~]# kubectl describe pod nginx
Name:         nginx
Namespace:    default
Priority:     0
Node:         node1.example.com/192.168.235.172
Start Time:   Mon, 20 Dec 2021 22:14:38 +0800
Labels:       app=nginx
   ································          
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx                     1/1     Running   0          87s


...
  labels:
    app: test		//将原本的nginx改为test
  name: nginx
[root@master ~]# kubectl describe pod nginx
...
Labels:       app=test

scale

扩容或缩容 Deployment、ReplicaSet、Replication Controller或 Job 中Pod数量
将名为nginx中的pod副本数量设置为3

[root@master ~]# kubectl get deployment
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           8m30s
[root@master ~]# kubectl scale --replicas 3 deployment/nginx
deployment.apps/nginx scaled
[root@master ~]# kubectl get deployment
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/3     3            1           8m56s
[root@master ~]# kubectl get pod
NAME                     READY   STATUS    RESTARTS   AGE
nginx-6799fc88d8-5tsjt   1/1     Running   0          16s
nginx-6799fc88d8-dwrsh   1/1     Running   0          9m5s
nginx-6799fc88d8-sn82p   1/1     Running   0          15s

如果当前副本数为3，则将其扩展至5

[root@master ~]# kubectl scale --current-replicas 3 --replicas 5 deployment/nginx
deployment.apps/nginx scaled
[root@master ~]# kubectl get pod
NAME                     READY   STATUS              RESTARTS   AGE
nginx-6799fc88d8-5tsjt   1/1     Running             0          62s
nginx-6799fc88d8-dwrsh   1/1     Running             0          9m51s
nginx-6799fc88d8-jkmln   0/1     ContainerCreating   0          2s
nginx-6799fc88d8-qm5ld   0/1     ContainerCreating   0          2s
nginx-6799fc88d8-sn82p   1/1     Running             0          61s
[root@master ~]# kubectl get deployment
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   4/5     5            4           9m58s

autoscale

自动扩展，给定一个范围，自动根据业务的访问量增加或减少
设定nginx这个deployment的副本数最少为1，最多为5

[root@master ~]# kubectl autoscale --min 1 --max 5 deployment/nginx
horizontalpodautoscaler.autoscaling/nginx autoscaled
[root@master ~]# kubectl get hpa
NAME    REFERENCE          TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
nginx   Deployment/nginx   <unknown>/80%   1         5         0          8s

cluster-info

显示标签为 kubernetes.io/cluster-service=true 的控制平面和服务的地址。要进一步调试和诊断集群问题，请使用“kubectl cluster-info dump”

[root@master ~]# kubectl cluster-info
Kubernetes control plane is running at https://192.168.164.141:6443
KubeDNS is running at https://192.168.235.179:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

describe

查看特定资源或资源组的详细信息

查看名为nginx 的pod的详细信息

[root@master ~]# kubectl describe pod nginx
Name:         nginx-6799fc88d8-5tsjt
Namespace:    default
Priority:     0
Node:         node1.example.com/192.168.235.172
Start Time:   Mon, 20 Dec 2021 22:23:28 +0800
Labels:       app=nginx
              pod-template-hash=6799fc88d8
Annotations:  <none>
Status:       Running
IP:           10.244.1.5
IPs:
  IP:           10.244.1.5
Controlled By:  ReplicaSet/nginx-6799fc88d8
Containers:
  nginx:
    Container ID:   docker://5a331ad8c751b41bfa7fd98f4f73e1c97cbc9f8aa76aada48f0be3fe22c10097
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:9522864dd661dcadfd9958f9e0de192a1fdda2c162a35668ab6ac42b465f0603
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Mon, 20 Dec 2021 22:23:37 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-n67dr (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-n67dr:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-n67dr
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  8m9s  default-scheduler  Successfully assigned default/nginx-6799fc88d8-5tsjt to node1.example.com
  Normal  Pulling    8m8s  kubelet            Pulling image "nginx"
  Normal  Pulled     8m    kubelet            Successfully pulled image "nginx" in 7.583042375s
  Normal  Created    8m    kubelet            Created container nginx
  Normal  Started    8m    kubelet            Started container nginx

logs

输出pod或指定资源中容器的日志。如果pod中只有一个容器，则容器名是可选的

// 查看nginx的日志
[root@master ~]# kubectl logs deployment/nginx
Found 5 pods, using pod/nginx-6799fc88d8-dwrsh
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2021/12/20 14:14:43 [notice] 1#1: using the "epoll" event method
2021/12/20 14:14:43 [notice] 1#1: nginx/1.21.4
2021/12/20 14:14:43 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2021/12/20 14:14:43 [notice] 1#1: OS: Linux 4.18.0-257.el8.x86_64
2021/12/20 14:14:43 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2021/12/20 14:14:43 [notice] 1#1: start worker processes
2021/12/20 14:14:43 [notice] 1#1: start worker process 32
2021/12/20 14:14:43 [notice] 1#1: start worker process 33

attach

连接到一个正在运行的容器

//获取正在运行中的pod nginx的输出，默认连接到pod中的第一个容器

[root@master ~]# kubectl attach nginx
Defaulting container name to nginx.
Use 'kubectl describe pod/nginx -n default' to see all of the containers in this pod.
If you don't see a command prompt, try pressing enter.

exec

在容器内执行命令

//默认在pod/nginx的第一个容器中运行date并打印输出
[root@master ~]# kubectl exec deployment/nginx date
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Mon Dec 20 14:38:25 UTC 2021

port-forward

将一个或多个本地端口转发到pod

//将容器中的80端口随即映射到本机的端口

[root@master ~]# kubectl port-forward nginx-6799fc88d8-5tsjt :80
Forwarding from 127.0.0.1:46459 -> 80
Forwarding from [::1]:46459 -> 80

[root@master ~]# curl 127.0.0.1:46459
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

cp

将文件和目录复制到容器或者从容器中拷贝

//将本地的anaconda-ks.cfg文件传输到pod/nginx的/tmp目录下
[root@master ~]# kubectl cp anaconda-ks.cfg nginx-6799fc88d8-5tsjt:/tmp
[root@master ~]# kubectl exec pod/nginx-6799fc88d8-5tsjt -- ls -l /tmp
total 4
-rw------- 1 root root 1252 Dec 20 14:48 anaconda-ks.cfg

label

更新（增加、修改或删除）资源上的 label（标签）

• label 必须以字母或数字开头，可以使用字母、数字、连字符、点和下划线，最长63个字符。
• 如果–overwrite 为 true，则可以覆盖已有的 label，否则尝试覆盖 label 将会报错。
• 如果指定了–resource-version，则更新将使用此资源版本，否则将使用现有的资源版本。

/更改标签
[root@master ~]# kubectl describe deployment/nginx
Name:                   nginx
Namespace:              default
CreationTimestamp:      Mon, 20 Dec 2021 22:14:38 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=nginx
Replicas:               5 desired | 5 updated | 5 total | 5 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=nginx
  Containers:
   nginx:
    Image:        nginx
    Port:         <none>
    Host Port:    <none>
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Progressing    True    NewReplicaSetAvailable
  Available      True    MinimumReplicasAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-6799fc88d8 (5/5 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  37m   deployment-controller  Scaled up replica set nginx-6799fc88d8 to 1
  Normal  ScalingReplicaSet  29m   deployment-controller  Scaled up replica set nginx-6799fc88d8 to 3
  Normal  ScalingReplicaSet  28m   deployment-controller  Scaled up replica set nginx-6799fc88d8 to 5

//追加标签
[root@master ~]# kubectl label deployment/nginx user=yaya
deployment.apps/nginx labeled
[root@master ~]# kubectl describe deployment/nginx
Name:                   nginx
Namespace:              default
CreationTimestamp:      Mon, 20 Dec 2021 22:14:38 +0800
Labels:                 app=nginx
                        user=yaya

api-resources

在服务器上打印支持的 API 资源

//查看所有资源
[root@master ~]# kubectl api-resources
NAME                              SHORTNAMES   APIVERSION                             NAMESPACED   KIND
bindings                                       v1                                     true         Binding
componentstatuses                 cs           v1                                     false        ComponentStatus
configmaps                        cm           v1                                     true         ConfigMap

api-versions

在服务器上以’组/版本’的形式打印支持的api版本

[root@master ~]#  kubectl api-versions
admissionregistration.k8s.io/v1
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1

rollout 回滚

有效类型

• deployments
• daemonsets
• statefulsets

[root@master ~]# kubectl create deployment nginx --image nginx
deployment.apps/nginx created

// 回本成功
[root@master ~]# kubectl rollout status deployments/nginx
deployment "nginx" successfully rolled out
更新版本之后才能看见回本效果

注意：rollout不能回滚pod和svc类型

[root@master ~]# kubectl get pods
NAME                     READY   STATUS      RESTARTS   AGE
test                     1/1     Running     0          61m

[root@master ~]# kubectl rollout status pod/test
error: no status viewer has been implemented for Pod

[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   46h
nginx        ClusterIP   10.108.208.249   <none>        80/TCP    68m

[root@master ~]# kubectl rollout status svc/nginx
error: no status viewer has been implemented for Service