云原生之kubectl命令详解（二）及pod的相关操作

忘是亡心i 2024-04-01 14:27 75阅读 0赞

**目录**

一、kubectl命令详解

1、查看某个资源的详细信息：kubectl describe pod pod\_name -n nameapace

2、查看指定命名空间中pod的基本信息：kubectl get pods -n namespace

3、跨主机登录容器：kubectl exec -it pod\_name /bin/bash -n namespace

4、删除pod

4.1、直接删除pod。但是deployment，副本控制器还在，他就会自己再创建一个。

①、直接删除POD

②、查看，发现与原先pod\_name不一样，

4.2、删除pod副本控制器deployment:

4.3、如果删除过程中出现幺蛾子，Pod无法删除，总是处于terminating状态，则执行强行删除--force --grace-period=0

5、命令行扩容和缩容

5.1、副本集的扩容

①查看原有副本集：1个

②扩容副本集为4

5.2、副本集的缩容

6、删除service

7、查看pod网络状态详情信息和service暴露的端口

8、查看关联后的节点

9、查看service的描述信息

二、pod的生命周期

1、创建一个Pod，启动nginx实例，暴露容器80端口，设置副本集为3（创建pod）

namespace为默认

2、 发布：kubectl expose命令 编辑

3、 查看端口

三、 service的type类型

--------------------

## 一、kubectl命令详解 ##

## 1、查看某个资源的详细信息：kubectl describe pod pod\_name -n nameapace（不加-n namespace 默认为查看default命名空间资源） ##

> \[root@master ~\]\# kubectl describe pods -n kube-public
> 
> \#\#\# 查看指定命名空间中的pod的详细信息
> 
> \#\#\# 在处理故障时，常使用此命令查看pod 的events信息来定位问题

Name:         nginx-w1-7464d66457-psk6h
    Namespace:    kube-public
    Priority:     0
    Node:         node01/192.168.159.11
    Start Time:   Wed, 02 Nov 2022 01:40:47 +0800
    Labels:       app=nginx-w1
                  pod-template-hash=7464d66457
    Annotations:  <none>
    Status:       Running
    IP:           10.150.1.3
    IPs:
      IP:           10.150.1.3
    Controlled By:  ReplicaSet/nginx-w1-7464d66457
    Containers:
      nginx:
        Container ID:   docker://4011df060a9ad777793f061675fc1a784f4effe56f5585d91d5ba3670660c620
        Image:          nginx
        Image ID:       docker-pullable://nginx@sha256:943c25b4b66b332184d5ba6bb18234273551593016c0e0ae906bab111548239f
        Port:           <none>
        Host Port:      <none>
        State:          Running
          Started:      Wed, 02 Nov 2022 01:41:06 +0800
        Ready:          True
        Restart Count:  0
        Environment:    <none>
        Mounts:
          /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-llzgh (ro)
    Conditions:
      Type              Status
      Initialized       True 
      Ready             True 
      ContainersReady   True 
      PodScheduled      True 
    Volumes:
      kube-api-access-llzgh:
        Type:                    Projected (a volume that contains injected data from multiple sources)
        TokenExpirationSeconds:  3607
        ConfigMapName:           kube-root-ca.crt
        ConfigMapOptional:       <nil>
        DownwardAPI:             true
    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:                      <none>
    
    
    Name:         nginx-x1-77484d895f-ddhqt
    Namespace:    kube-public
    Priority:     0
    Node:         node02/192.168.159.13
    Start Time:   Thu, 03 Nov 2022 16:16:11 +0800
    Labels:       app=nginx-x1
                  pod-template-hash=77484d895f
    Annotations:  <none>
    Status:       Running
    IP:           10.150.2.3
    IPs:
      IP:           10.150.2.3
    Controlled By:  ReplicaSet/nginx-x1-77484d895f
    Containers:
      nginx:
        Container ID:   docker://ecc07803682f2d7a51037024354dae0d190841443121ca0a8514ab224179cbf5
        Image:          nginx:latest
        Image ID:       docker-pullable://nginx@sha256:943c25b4b66b332184d5ba6bb18234273551593016c0e0ae906bab111548239f
        Port:           <none>
        Host Port:      <none>
        State:          Running
          Started:      Thu, 03 Nov 2022 16:16:36 +0800
        Ready:          True
        Restart Count:  0
        Environment:    <none>
        Mounts:
          /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-47hxr (ro)
    Conditions:
      Type              Status
      Initialized       True 
      Ready             True 
      ContainersReady   True 
      PodScheduled      True 
    Volumes:
      kube-api-access-47hxr:
        Type:                    Projected (a volume that contains injected data from multiple sources)
        TokenExpirationSeconds:  3607
        ConfigMapName:           kube-root-ca.crt
        ConfigMapOptional:       <nil>
        DownwardAPI:             true
    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:                      <none>

## 2、查看指定命名空间中pod的基本信息：kubectl get pods -n namespace ##

> \[root@master ~\]\# kubectl get pods -n kube-public \[-o wide\] \#\#\# \[-o wide\] 显示详细信息

NAME                        READY   STATUS    RESTARTS   AGE
    nginx-w1-7464d66457-psk6h   1/1     Running   0          43h
    nginx-x1-77484d895f-ddhqt   1/1     Running   0          5h12m

## 3、跨主机登录容器：kubectl exec -it pod\_name /bin/bash -n namespace ##

> root@master ~\]\# kubectl exec -it nginx-x1-77484d895f-ddhqt /bin/bash -n kube-public
> 
> 例如：
> 
> root@master ~\]\# kubectl exec -it nginx-x1-77484d895f-ddhqt ifconfig \#\#\# 不进入容器直接使用命令

[root@master ~]# kubectl exec -it nginx-x1-77484d895f-ddhqt /bin/bash -n kube-public
    kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
    root@nginx-x1-77484d895f-ddhqt:/#

## 4、删除pod ##

### 4.1、直接删除pod。但是deployment，副本控制器还在，他就会自己再创建一个。 ###

> \[root@master ~\]\# kubectl delete pod nginx -n kube-public  
> pod "nginx-w1-7464d66457-psk6h" deleted

#### ①、直接删除POD ####

![a71d0e905dce4656901de50d02161d57.png][]

#### ②、查看，发现与原先pod\_name不一样， ####

![0413961fccff49548b94e31c36533c81.png][]

### 4.2、删除pod副本控制器deployment: ###

> \[root@master ~\]\# kubectl delete deployment nginx-w1 -n kube-public

#### ![cd645953179345969278c1d525a9141c.png][] ####

### 4.3、如果删除过程中出现幺蛾子，Pod无法删除，总是处于terminating状态，则执行强行删除--force --grace-period=0 ###

强行删除pod

## 5、命令行扩容和缩容 ##

### 5.1、副本集的扩容 ###

#### ①查看原有副本集：1个 ####

![d527604b82d64b84b5ab7afb253b7f0f.png][]

#### ②扩容副本集为4 ####

![1cf6a3c96a2d4303a5999623cc7135eb.png][]

### 5.2、副本集的缩容 ###

基于上面结果进行实验，设置--replicas=2，指定副本集数量后，他会根据现有的副本集数量和期望值相比较，从而决定时扩容还是缩容

![9cf8f58d40064930ba43ce0655f4f446.png][]

## 6、删除service ##

> \[root@master ~\]\# kubectl delete svc nginx-server -n default

[root@master ~]# kubectl get svc -n default
    NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
    kubernetes      ClusterIP   10.125.0.1      <none>        443/TCP        2d6h
    nginx-server    NodePort    10.125.126.34   <none>        80:30537/TCP   45m
    nginx1-server   NodePort    10.125.103.25   <none>        80:31070/TCP   2m41s
    [root@master ~]# kubectl delete svc nginx-server -n default
    service "nginx-server" deleted

## 7、查看pod网络状态详情信息和service暴露的端口 ##

> \[root@master ~\]\# kubectl get svc,pods -n default

## ![cfe1e2816c9a45199690db159e628d82.png][] ##

## 8、查看关联后的节点 ##

> \[root@master ~\]\# kubectl get endpoints

[root@master ~]# kubectl get endpoints
    NAME             ENDPOINTS                                    AGE
    kubernetes       192.168.159.10:6443                          2d6h
    nginx1-service   10.150.1.10:80,10.150.1.9:80,10.150.2.9:80   32m

## 9、查看service的描述信息 ##

> \[root@master ~\]\# kubectl describe svc nginx

[root@master ~]# kubectl describe svc nginx
    Name:                     nginx1-service
    Namespace:                default
    Labels:                   app=nginx
    Annotations:              <none>
    Selector:                 app=nginx
    Type:                     NodePort
    IP Family Policy:         SingleStack
    IP Families:              IPv4
    IP:                       10.125.32.0
    IPs:                      10.125.32.0
    Port:                     <unset>  80/TCP
    TargetPort:               80/TCP
    NodePort:                 <unset>  31625/TCP
    Endpoints:                10.150.1.10:80,10.150.1.9:80,10.150.2.9:80
    Session Affinity:         None
    External Traffic Policy:  Cluster
    Events:                   <none>

## 10、核心组件查看日志 ##

> 通过kubeadm方式部署的K8S
> 
> kubectl logs -f pod\_name -n namespace 或者 journalctl -u kubelet -f
> 
> \#\#\# kubectl logs -f 持续输出打印
> 
> \#\#\# kubectl logs 只打印当前时刻

> 通过二进制部署的K8S
> 
> journalctl -u kubelet -f

## 二、pod的生命周期 ##

pod生命周期是指：pod在从创建到删除过程中，所包含、经历的状态

**pod的类型分为2中：**

**①、自主式：没有控制器管理的就是自助式的。删除时直接删除就行**

**②、申明式：有控制器管理的Pod。(我们一般使用的类型)**

## 1、创建一个Pod，启动nginx实例，暴露容器80端口，设置副本集为3（创建pod） ##

## namespace为默认 ##

> \[root@master ~\]\# kubectl create deployment nginx-ceshi --image=nginx:1.14 --port 80 --replicas=3  
> deployment.apps/nginx-ceshi created  
>

![656c4836c25f443d852e4125f26ff244.png][]

## 2、 发布：kubectl expose命令 ![724db4b747764c88920399591a8260e5.png][] ##

## 3、 查看端口 ##

![91a464ce3258481ca12126e500e5dd08.png][]

## ![00ec5ce894ce461898d75673379bfd2c.png][]三、 service的type类型 ##

①、clusterIP:提供一个集群内部的虚拟IP以供Pod访问(service默认类型)

②、NodePort:在每个Node上打开一个端口以供外部访问，Kubernetes将会在每个Node上打开一个端口并且每个Node的端口都是一样的，通过 NodeIp:NodePort 的方式Kubernetes集群外部的程序可以访问service。每个端口只能是一种服务，端口范围只能是30000-32767

③、LoadBalancer:通过设置LoadBalancer映射到云服务商提供的LoadBalancer地址。这种用法仅用于在公有云服务提供商的云平台上设置service的场景。通过外部的负载均衡器来访问，通常在云平台部署LoadBalancer还需要额外的费用。

④、externalName:将service名称映射到一个DNS域名上，相当于DNS服务的CNAME记录，用于让Pod去访问集群外部的资源，它本身没有绑定任何的资源。

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