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K8s练习

news 2025/10/31 10:54:44

K8s命令

查看所有命名空间

[root@master ~]# kubectl get ns
NAME              STATUS   AGE
cy                Active   22h
default           Active   41h
kube-node-lease   Active   41h
kube-public       Active   41h
kube-system       Active   41h
xy                Active   13h

查看指定ns

[root@master ~]# kubectl get ns xy
NAME   STATUS   AGE
xy     Active   13h

查看ns的yaml格式

[root@master ~]# kubectl get ns xy -o yaml
apiVersion: v1
kind: Namespace
metadata:annotations:kubectl.kubernetes.io/last-applied-configuration: |{"apiVersion":"v1","kind":"Namespace","metadata":{"annotations":{},"name":"xy"}}creationTimestamp: "2025-10-29T11:45:27Z"labels:kubernetes.io/metadata.name: xyname: xyresourceVersion: "30668"uid: f70ca315-1aec-44c3-a530-f4a3635df45f
spec:finalizers:- kubernetes
status:phase: Active

详细查看ns

[root@master ~]# kubectl describe ns xy
Name:         xy
Labels:       kubernetes.io/metadata.name=xy
Annotations:  <none>
Status:       ActiveNo resource quota.No LimitRange resource.

创建ns

[root@master ~]# kubectl create ns test1
namespace/test1 created
[root@master ~]# kubectl get ns
NAME              STATUS   AGE
cy                Active   22h
default           Active   41h
kube-node-lease   Active   41h
kube-public       Active   41h
kube-system       Active   41h
test1             Active   6s
xy                Active   13h

删除ns

[root@master ~]# kubectl delete ns test1
namespace "test1" deleted
[root@master ~]# kubectl get ns
NAME              STATUS   AGE
cy                Active   22h
default           Active   41h
kube-node-lease   Active   41h
kube-public       Active   41h
kube-system       Active   41h
xy                Active   13h

pod

查看集群的各个组件

[root@master ~]# kubectl get pods -n kube-system 
NAME                                      READY   STATUS    RESTARTS      AGE
calico-kube-controllers-9d57d8f49-mndtc   1/1     Running   5 (21m ago)   41h
calico-node-n954f                         1/1     Running   6 (21m ago)   41h
calico-node-s4mtv                         1/1     Running   6 (21m ago)   41h
calico-node-sk2bk                         1/1     Running   6 (21m ago)   41h
coredns-6554b8b87f-mnw6s                  1/1     Running   5 (21m ago)   41h
coredns-6554b8b87f-zj9hd                  1/1     Running   5 (21m ago)   41h
etcd-master                               1/1     Running   6 (21m ago)   41h
kube-apiserver-master                     1/1     Running   6 (21m ago)   41h
kube-controller-manager-master            1/1     Running   6 (21m ago)   41h
kube-proxy-76llz                          1/1     Running   6 (21m ago)   41h
kube-proxy-mkf5f                          1/1     Running   6 (21m ago)   41h
kube-proxy-ztbz2                          1/1     Running   6 (21m ago)   41h
kube-scheduler-master                     1/1     Running   6 (21m ago)   41h

kubernetes没有提供单独运行Pod的命令，都是通过Pod控制器来实现的

#创建并运行pod
[root@master ~]# kubectl run nginx --image=nginx:latest --port=80 --namespace xy
pod/nginx created

查看pod信息

[root@master ~]# kubectl get pods -n xy
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          48s

查看详细信息

[root@master ~]# kubectl describe pod nginx -n xy
Name:             nginx
Namespace:        xy
Priority:         0
Service Account:  default
Node:             node1/192.168.100.10
Start Time:       Thu, 30 Oct 2025 15:12:23 +0800
Labels:           run=nginx
.....

访问pod

#通过 -o wide能够看到pod的ip
[root@master ~]# kubectl get pods nginx -n xy -o wide
NAME    READY   STATUS    RESTARTS   AGE     IP               NODE    NOMINATED NODE   READINESS GATES
nginx   1/1     Running   0          2m48s   172.16.166.135   node1   <none>           <none>[root@node1 ~]# curl http://172.16.166.135
<!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>

删除pod

[root@master ~]# kubectl delete pod nginx -n xy
pod "nginx" deleted
[root@master ~]# kubectl get pods -n xy
No resources found in xy namespace.

通过pod控制器创建pod

[root@master ~]# kubectl create deployment nginx --image=nginx:latest --port 80 -n xy
deployment.apps/nginx created
#查看pod
[root@master ~]# kubectl get pod -n xy
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7c79c4bf97-4xgfj   1/1     Running   0          30s
#删除pod
[root@master ~]# kubectl delete pod nginx-7c79c4bf97-4xgfj -n xy
pod "nginx-7c79c4bf97-4xgfj" deleted
#可以看到已经删除了，再次查看pod
[root@master ~]# kubectl get pod -n xy
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7c79c4bf97-89xzz   1/1     Running   0          28s
#还是有pod，这是因为pod是由pod控制器创建，当前pod故障或死亡时，pod控制器会重建pod，想要删除pod，就要删除pod控制器
#删除pod控制器
[root@master ~]# kubectl delete deploy nginx -n xy
deployment.apps "nginx" deleted
#再次查看pod
[root@master ~]# kubectl get pod -n xy
No resources found in xy namespace.

创建一个test.yaml文件，如果不知道格式可以去官网查

官网：https://kubernetes.io/docs/home/

apiVersion: v1
kind: Pod
metadata:name: nginx
spec:containers:- name: nginximage: nginx:latestports:- containerPort: 80
[root@master ~]# kubectl apply -f test.yaml 
pod/nginx created
[root@master ~]# kubectl get pods
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          8s
#没有指定命名空间的pod会放在默认空间里面

Deployment

Deployment是pod控制器的一种

格式：kubectl create deployment 名称 [参数]

–image 指定pod的镜像

–port 指定端口

–replicas 指定创建pod数量

–namespace 指定namespace

[root@master ~]# kubectl create deploy nginx --image=nginx:latest --port=80 --replicas=3 -n xy
deployment.apps/nginx created

查看pod

[root@master ~]# kubectl get pods -n xy
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7c79c4bf97-2v69g   1/1     Running   0          21s
nginx-7c79c4bf97-5kzn6   1/1     Running   0          21s
nginx-7c79c4bf97-nmbwq   1/1     Running   0          21s

查看deploy的信息

[root@master ~]# kubectl get deploy -n xy
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   3/3     3            3           49s
# UP-TO-DATE：成功升级的副本数量
# AVAILABLE：可用副本的数量
[root@master ~]# kubectl get deploy -n xy -o wide
NAME    READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES         SELECTOR
nginx   3/3     3            3           94s   nginx        nginx:latest   app=nginx

查看deploy的详细信息

[root@master ~]# kubectl describe deploy nginx -n xy
Name:                   nginx
Namespace:              xy
CreationTimestamp:      Thu, 30 Oct 2025 16:10:39 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=nginx
Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:Labels:  app=nginx
.......

删除

[root@master ~]# kubectl delete deploy nginx -n xy
deployment.apps "nginx" deleted

创建一个deploy-nginx.yaml文件

apiVersion: apps/v1
kind: Deployment
metadata:name: nginxnamespace: dev
spec:replicas: 3selector:matchLabels:run: nginxtemplate:metadata:labels:run: nginxspec:containers:- image: nginx:latestname: nginxports:- containerPort: 80protocol: TCP

Label

Label 的特点

以 key/value 键值对的形式附加到各种对象上（如 Node、Pod、Service 等）
一个资源对象可以定义任意数量的 Label
同一个 Label 可以被添加到任意数量的资源对象上
Label 通常在资源对象定义时确定，也可以在对象创建后动态添加或删除
通过 Label 实现资源的多维度分组，便于资源分配、调度、配置、部署等管理工作

Label 的常用示例

标签类型	示例
版本标签	`"version":"release"`, `"version":"stable"`
环境标签	`"environment":"dev"`, `"environment":"test"`, `"environment":"pro"`
架构标签	`"tier":"frontend"`, `"tier":"backend"`

当前有两种Label Selector：
基于等式的Label Selector
name = slave: 选择所有包含Label中key="name"且value="slave"的对象
env != production: 选择所有包括Label中的key="env"且value不等于"production"的对象
基于集合的Label Selector
name in (master, slave): 选择所有包含Label中的key="name"且value="master"或"slave"的对象
name not in (frontend): 选择所有包含Label中的key="name"且value不等于"frontend"的对象
标签的选择条件可以使用多个，此时将多个Label Selector进行组合，使用逗号","进行分隔即可。例如：
name=slave，env!=production
name not in (frontend)，env!=production

为pod打标签

[root@master ~]# kubectl label pod nginx t1=10 -n xy
pod/nginx labeled
#查看
[root@master ~]# kubectl get pod nginx -n xy --show-labels
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          60s   t1=10
#更新标签
[root@master ~]# kubectl label pod nginx t1=20 -n xy --overwrite
pod/nginx labeled
#查看
[root@master ~]# kubectl get pod nginx -n xy --show-labels
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          11m   t1=20
#筛选标签
[root@master ~]# kubectl label pod nginx t2=20 -n xy 
pod/nginx labeled
[root@master ~]# kubectl get pod -n xy -l t1=20 --show-labels 
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          18m   t1=20,t2=20
[root@master ~]# kubectl get pod -n xy -l t1!=20 --show-labels 
NAME       READY   STATUS    RESTARTS   AGE   LABELS
nginxpod   1/1     Running   0          19m   <none>
#删除标签
[root@master ~]# kubectl label pod nginx t1- -n xy
pod/nginx unlabeled
#在标签后面加上-

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