k8s入门实战(Pod-Label-Deployment)

Pod

Pod 是可以在 Kubernetes 中创建和管理的、最小的可部署的计算单元。

k8s架构图：
在这里插入图片描述

k8s集群启动后，集群中各个组件也是以pod方式运行

[root@master ~]# kubectl get pod -n kube-system
NAME                             READY   STATUS    RESTARTS   AGE
coredns-6955765f44-7jflq         1/1     Running   1          17h
coredns-6955765f44-9h9s9         1/1     Running   1          17h
etcd-master                      1/1     Running   1          17h
kube-apiserver-master            1/1     Running   1          17h
kube-controller-manager-master   1/1     Running   1          17h
kube-proxy-gz5r2                 1/1     Running   1          17h
kube-proxy-hk8d5                 1/1     Running   1          17h
kube-proxy-vln9d                 1/1     Running   1          17h
kube-scheduler-master            1/1     Running   1          17h

创建并运行

k8s没有提供单独命令运行，是通过pod控制器运行

 #首先查看名称空间
[root@master ~]# kubectl get ns
NAME              STATUS   AGE
default           Active   17h
dev               Active   80m   #把pod运行在这个ns里
kube-flannel      Active   17h
kube-node-lease   Active   17h
kube-public       Active   17h
kube-system       Active   17h 

#命令格式 kubectl run (pod控制器名称)[参数]
#--image 指定pod镜像 --port 指定端口 --namespace 指定名称空间


[root@master ~]# kubectl run nginx --image=nginx:1.17.1 --port=80 --namespace dev
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created 

#查询pod
 #这个pod刚刚部署到node1节点 启动了71s
[root@master ~]# kubectl get pod -n dev -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP           NODE    NOMINATED NODE   READINESS GATES
nginx-64777cd554-p5nvj   1/1     Running   0          71s   10.244.1.5   node1   <none>           <none>
nginxpod                 1/1     Running   1          85m   10.244.2.8   node2   <none>           <none>

通过刚刚创建的pod IP和端口访问页面

[root@master ~]# curl 10.244.1.5:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    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>

删除pod

#查看pod
[root@master ~]# kubectl get pod -n dev
NAME                     READY   STATUS    RESTARTS   AGE
nginx-64777cd554-p5nvj   1/1     Running   0          13m
nginxpod                 1/1     Running   1          98m

#查看pod控制器
[root@master ~]# kubectl get deployment -n dev
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           15m

 #如果删除了pod控制器 pod就自动删除  如果仅仅删除了pod pod控制器 
#还会给你创建一个新的

[root@master ~]# kubectl delete  deployment nginx -n dev
deployment.apps "nginx" deleted
[root@master ~]# kubectl get pod -n dev
NAME       READY   STATUS    RESTARTS   AGE
nginxpod   1/1     Running   1          102m

配置操作

创建pod-nginx.yaml

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  namespace: dev
spec:
  containers:
  - image: nginx:1.17.1
    name: pod
    ports:
    - name: nginx-port
      containerPort: 80
      protocol: TCP

#运行pod
[root@master ~]# kubectl create -f pod-nginx.yaml
pod/nginx created 


#查询
[root@master ~]# kubectl get pod -n dev
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          51s 


#删除pod
[root@master ~]# kubectl delete -f pod-nginx.yaml
pod "nginx" deleted
[root@master ~]# kubectl get pod -n dev
No resources found in dev namespace.

Label

标签（Labels） 是附加到 Kubernetes 对象（比如 Pod）上的键值对。标签旨在用于指定对用户有意义且相关的对象的标识属性，但不直接对核心系统有语义含义。标签可以用于组织和选择对象的子集。标签可以在创建时附加到对象，随后可以随时添加和修改。每个对象都可以定义一组键/值标签。每个键对于给定对象必须是唯一的。

简单来说就是一种标识选择机制

一个Label会以key/value键值对形式附加到各种资源对象上
一个资源可以打上多个标签，一个标签可以给多个资源对象定义
Label通常资源对象定义时确定，也可以在资源运行时定义

"metadata": {
  "labels": {
    "key1" : "value1",
    "key2" : "value2"
  }
}

标签定义完后还有注意标签选择

Label Selector

标签不支持唯一性。通常，我们希望许多对象携带相同的标签。

通过标签选择算符，客户端/用户可以识别一组对象。标签选择算符是 Kubernetes 中的核心分组原语。

API 目前支持两种类型的选择算符：基于等值的和基于集合的。标签选择算符可以由逗号分隔的多个需求组成。在多个需求的情况下，必须满足所有要求，因此逗号分隔符充当逻辑与（&&）运算符。

空标签选择算符或者未指定的选择算符的语义取决于上下文，支持使用选择算符的 API 类别应该将算符的合法性和含义用文档记录下来。

基于等值或基于不等值的需求允许按标签键和值进行过滤。匹配对象必须满足所有指定的标签约束，尽管它们也可能具有其他标签。可接受的运算符有 =、== 和 != 三种。前两个表示相等（并且是同义词），而后者表示不相等。例如：

environment = production
tier != frontend

前者选择所有资源，其键名等于 environment，值等于 production。后者选择所有资源，其键名等于 tier，值不同于 frontend，所有资源都没有带有 tier 键的标签。可以使用逗号运算符来过滤 production 环境中的非 frontend 层资源：environment=production,tier!=frontend。

基于等值的标签要求的一种使用场景是 Pod 要指定节点选择标准。例如，下面的示例 Pod 选择带有标签 “accelerator=nvidia-tesla-p100”。

apiVersion: v1
kind: Pod
metadata:
  name: cuda-test
spec:
  containers:
    - name: cuda-test
      image: "registry.k8s.io/cuda-vector-add:v0.1"
      resources:
        limits:
          nvidia.com/gpu: 1
  nodeSelector:
    accelerator: nvidia-tesla-p100

基于集合的标签需求允许你通过一组值来过滤键。支持三种操作符：in、notin 和 exists（只可以用在键标识符上）。例如：

environment in (production, qa)
tier notin (frontend, backend)
partition
!partition

第一个示例选择了所有键等于 environment 并且值等于 production 或者 qa 的资源。
第二个示例选择了所有键等于 tier 并且值不等于 frontend 或者 backend 的资源，以及所有没有 tier 键标签的资源。
第三个示例选择了所有包含了有 partition 标签的资源；没有校验它的值。
第四个示例选择了所有没有 partition 标签的资源；没有校验它的值。

命令方式

#根据上文中的ymal文件，创建一个pod  
[root@master ~]# kubectl create -f pod-nginx.yaml
pod/nginx created
[root@master ~]# kubectl get pod -n dev
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          21s
[root@master ~]# kubectl get pod -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          49s   <none>


#给pod打标签

[root@master ~]# kubectl label pod nginx -n dev version=1.0
pod/nginx labeled
[root@master ~]# kubectl get pod -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE    LABELS
nginx   1/1     Running   0          2m7s   version=1.0


[root@master ~]# kubectl get pod -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE     LABELS
nginx   1/1     Running   0          2m56s   tier=back,version=1.0

#更新标签
[root@master ~]# kubectl label pod nginx -n dev version=2.0 --overwrite
pod/nginx labeled
[root@master ~]# kubectl get pod -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE     LABELS
nginx   1/1     Running   0          4m36s   tier=back,version=2.0 


#更改yaml文件，再新建一个pod
[root@master ~]# vim pod-nginx.yaml
[root@master ~]# cat pod-nginx.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx1
  namespace: dev
spec:
  containers:
  - image: nginx:1.17.1
    name: pod
    ports:
    - name: nginx-port
      containerPort: 80
      protocol: TCP


[root@master ~]# kubectl create -f pod-nginx.yaml
pod/nginx1 created 

#打标签

[root@master ~]# kubectl create -f pod-nginx.yaml
pod/nginx1 created


[root@master ~]# kubectl get pods -n dev --show-labels
NAME     READY   STATUS    RESTARTS   AGE     LABELS
nginx    1/1     Running   0          7m55s   tier=back,version=2.0
nginx1   1/1     Running   0          105s    version=1.0

#筛选
[root@master ~]# kubectl get pods -l "version=2.0" -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE     LABELS
nginx   1/1     Running   0          9m55s   tier=back,version=2.0
[root@master ~]# kubectl get pods -l "version!=2.0" -n dev --show-labels
NAME     READY   STATUS    RESTARTS   AGE     LABELS
nginx1   1/1     Running   0          3m59s   version=1.0 

#删除标签

[root@master ~]# kubectl label pod nginx -n dev tier-
pod/nginx labeled
[root@master ~]# kubectl get pods -l "version=2.0" -n dev --show-labels
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          13m   version=2.0

配置文件添加label

更新yaml文件内容

[root@master ~]# vim pod-nginx.yaml
[root@master ~]# cat pod-nginx.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  namespace: dev
  labels:
    version: "3.0"
    env: "test"
spec:
  containers:
  - image: nginx:1.17.1
    name: pod
    ports:
    - name: nginx-port
      containerPort: 80
      protocol: TCP
[root@master ~]# kubectl apply -f pod-nginx.yaml
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
pod/nginx configured
[root@master ~]# kubectl get pods  -n dev --show-labels
NAME     READY   STATUS    RESTARTS   AGE   LABELS
nginx    1/1     Running   0          58m   env=test,version=3.0
nginx1   1/1     Running   0          52m   version=1.0

Deployment

Pod控制器，用于Pod管理，保障Pod资源始终保存可预期状态

命令操作

# 命令格式: kubectl run 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na
mespace

[root@master ~]# kubectl run nginx --image=nginx:1.17.1 --port=80 --replicas=3 --namespace=dev
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created 


[root@master ~]# kubectl get deployment,pods -n dev
NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx   3/3     3            3           6s

NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-64777cd554-2txpz   1/1     Running   0          6s
pod/nginx-64777cd554-5j686   1/1     Running   0          6s
pod/nginx-64777cd554-z5psb   1/1     Running   0          6s  

#查看控制器信息

[root@master ~]# kubectl describe deploy nginx -n dev
Name:                   nginx
Namespace:              dev
CreationTimestamp:      Tue, 23 May 2023 02:59:31 -0400
Labels:                 run=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               run=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:  run=nginx
  Containers:
   nginx:
    Image:        nginx:1.17.1
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-64777cd554 (3/3 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  5m10s  deployment-controller  Scaled up replica set nginx-64777cd554 to 3

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

配置操作

创建一个yaml文件

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  namespace: dev
spec:
  replicas: 3
  selector:
    matchLabels:
      run: nginx
  template:
    metadata:
      labels:
        run: nginx
    spec:
      containers:
      - image: nginx:1.17.1
        name: nginx
        ports:
        - containerPort: 80
          protocol: TCP

[root@master ~]# vim deploy-nginx.yaml
[root@master ~]# cat deploy-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  namespace: dev
spec:
  replicas: 3
  selector:
    matchLabels:
      run: nginx
  template:
    metadata:
      labels:
        run: nginx
    spec:
      containers:
      - image: nginx:1.17.1
        name: nginx
        ports:
        - containerPort: 80
          protocol: TCP
[root@master ~]# kubectl create -f deploy-nginx.yaml
deployment.apps/nginx created
[root@master ~]# kubectl get deployment,pods -n dev
NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx   3/3     3            3           24s

NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-64777cd554-69c7c   1/1     Running   0          24s
pod/nginx-64777cd554-g4cpm   1/1     Running   0          24s
pod/nginx-64777cd554-zjzsx   1/1     Running   0          24s
  
#删除

[root@master ~]# kubectl delete -f deploy-nginx.yaml
deployment.apps "nginx" deleted
[root@master ~]# kubectl get deployment,pods -n dev #删除需要时间 正在删除中
NAME                         READY   STATUS        RESTARTS   AGE
pod/nginx-64777cd554-g4cpm   0/1     Terminating   0          78s
pod/nginx-64777cd554-zjzsx   0/1     Terminating   0          78s
[root@master ~]# kubectl get deployment,pods -n dev
NAME                         READY   STATUS        RESTARTS   AGE
pod/nginx-64777cd554-g4cpm   0/1     Terminating   0          86s
[root@master ~]# kubectl get deployment,pods -n dev
No resources found in dev namespace.