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[系统运维]Kubernetes CKA认证运维工程师笔记-Kubernetes应用程序生命周期管理

Kubernetes CKA认证运维工程师笔记-Kubernetes应用程序生命周期管理

1. 在Kubernetes中部署应用流程
2. 使用Deployment部署Java应用
- 2.1 Pod与Deployment的关系
- 2.2 Deployment控制器介绍
3. 服务编排（YAML）
4. 应用升级、弹性收缩、回滚、删除
5. 滚动升级与回滚实现机制
6. Pod对象：Pod设计思想、应用自修复、Init container、静态Pod

1. 在Kubernetes中部署应用流程

镜像基本分为三类：

基础镜像
运行环境镜像
项目镜像

在这里插入图片描述

2. 使用Deployment部署Java应用

0、制作镜像
1、使用Deployment控制器部署镜像
kubectl create deployment web --image=lizhenliang/java-demo
kubectl get deploy,pods
2、使用Service发布Pod
kubectl expose deployment web --port=80 --type=NodePort --target-port=8080 --name=web
kubectl get service

2.1 Pod与Deployment的关系

Deployment是最为常用的controllers（也称为workload），其他控制器还有DaemonSet、StatefulSet等。
controllers作用：

管理Pod对象
使用标签与Pod关联
控制器了Pod的运维，例如滚动更新、伸缩、副本管理、维护Pod状态等

2.2 Deployment控制器介绍

Deployment的功能：

管理Pod和ReplicaSet
具有上线部署、副本设定、滚动升级、回滚等功能
提供声明式更新，例如只更新一个新的Image

应用场景：网站、API、微服务

3. 服务编排（YAML）

3.1 服务编排：YAML文件创建资源对象

定义Deployment：

# 控制器定义
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
# 被控制对象
template:
  metadata:
    labels:
      app: nginx
  spec:
    containers:
    - name: nginx
      image: nginx:1.19
      ports:
      - containerPort: 80

[root@k8s-master ~]# vim deployment.yaml
[root@k8s-master ~]# cat deployment.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80
[root@k8s-master ~]# kubectl apply -f deployment.yaml 
deployment.apps/nginx-deployment created
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS              RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running             2          6d8h
my-dep-5f8dfc8c78-f4ln4             1/1     Running             2          6d8h
my-dep-5f8dfc8c78-j9fqp             1/1     Running             2          6d8h
nginx-deployment-7cf55fb7bb-d2t9n   0/1     ContainerCreating   0          14s
nginx-deployment-7cf55fb7bb-gbtfr   0/1     ContainerCreating   0          14s
nginx-deployment-7cf55fb7bb-npfqz   0/1     ContainerCreating   0          14s
nginx-php                           1/1     Running             1          47h
web-96d5df5c8-ghb6g                 1/1     Running             2          9d
web2                                1/1     Running             1          46h
[root@k8s-master ~]# kubectl get deployment
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
my-dep             3/3     3            3           6d8h
nginx-deployment   2/3     3            2           37s
web                1/1     1            1           9d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   2          6d8h
my-dep-5f8dfc8c78-f4ln4             1/1     Running   2          6d8h
my-dep-5f8dfc8c78-j9fqp             1/1     Running   2          6d8h
nginx-deployment-7cf55fb7bb-d2t9n   1/1     Running   0          54s
nginx-deployment-7cf55fb7bb-gbtfr   1/1     Running   0          54s
nginx-deployment-7cf55fb7bb-npfqz   1/1     Running   0          54s
nginx-php                           1/1     Running   1          47h
web-96d5df5c8-ghb6g                 1/1     Running   2          9d
web2                                1/1     Running   1          46h
[root@k8s-master ~]# kubectl get pods --show-labels
NAME                                READY   STATUS    RESTARTS   AGE     LABELS
my-dep-5f8dfc8c78-dvxp8             1/1     Running   2          6d8h    app=my-dep,pod-template-hash=5f8dfc8c78
my-dep-5f8dfc8c78-f4ln4             1/1     Running   2          6d8h    app=my-dep,pod-template-hash=5f8dfc8c78
my-dep-5f8dfc8c78-j9fqp             1/1     Running   2          6d8h    app=my-dep,pod-template-hash=5f8dfc8c78
nginx-deployment-7cf55fb7bb-d2t9n   1/1     Running   0          2m57s   app=nginx,pod-template-hash=7cf55fb7bb
nginx-deployment-7cf55fb7bb-gbtfr   1/1     Running   0          2m57s   app=nginx,pod-template-hash=7cf55fb7bb
nginx-deployment-7cf55fb7bb-npfqz   1/1     Running   0          2m57s   app=nginx,pod-template-hash=7cf55fb7bb
nginx-php                           1/1     Running   1          47h     run=nginx-php
web-96d5df5c8-ghb6g                 1/1     Running   2          9d      app=web,pod-template-hash=96d5df5c8
web2                                1/1     Running   1          46h     <none>

[root@k8s-master ~]# vim service.yaml 
[root@k8s-master ~]# cat service.yaml 
apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: NodePort
[root@k8s-master ~]# kubectl apply -f service.yaml 
service/my-service created
[root@k8s-master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        9d
my-dep       NodePort    10.111.199.51   <none>        80:31734/TCP   6d8h
my-service   NodePort    10.100.228.0    <none>        80:32433/TCP   12s
web          NodePort    10.96.132.243   <none>        80:31340/TCP   9d
[root@k8s-master ~]# kubectl get ep
NAME         ENDPOINTS                                                 AGE
kubernetes   10.0.0.61:6443                                            9d
my-dep       10.244.169.150:8080,10.244.36.84:8080,10.244.36.85:8080   6d8h
my-service   10.244.169.151:80,10.244.169.152:80,10.244.36.88:80       26s
web          10.244.36.86:80                                           9d
[root@k8s-master ~]# curl 10.100.228.0 
<!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>
[root@k8s-master ~]# kubectl get pods 
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   2          6d8h
my-dep-5f8dfc8c78-f4ln4             1/1     Running   2          6d8h
my-dep-5f8dfc8c78-j9fqp             1/1     Running   2          6d8h
nginx-deployment-7cf55fb7bb-d2t9n   1/1     Running   0          9m34s
nginx-deployment-7cf55fb7bb-gbtfr   1/1     Running   0          9m34s
nginx-deployment-7cf55fb7bb-npfqz   1/1     Running   0          9m34s
nginx-php                           1/1     Running   1          47h
web-96d5df5c8-ghb6g                 1/1     Running   2          9d
web2                                1/1     Running   1          46h
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-d2t9n
/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
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-gbtfr
/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
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-npfqz
/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
10.244.235.192 - - [01/Dec/2021:06:08:41 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.29.0" "-"
# 在浏览器里面输入IP地址加端口号
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-d2t9n
/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
10.244.235.192 - - [01/Dec/2021:06:12:32 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0" "-"
2021/12/01 06:12:32 [error] 32#32: *1 open() "/usr/share/nginx/html/favicon.ico" failed (2: No such file or directory), client: 10.244.235.192, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "10.0.0.61:32433", referrer: "http://10.0.0.61:32433/"
10.244.235.192 - - [01/Dec/2021:06:12:32 +0000] "GET /favicon.ico HTTP/1.1" 404 154 "http://10.0.0.61:32433/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0" "-"
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-gbtfr
/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
[root@k8s-master ~]# kubectl logs nginx-deployment-7cf55fb7bb-npfqz
/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
10.244.235.192 - - [01/Dec/2021:06:08:41 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.29.0" "-"


[root@k8s-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
batch/v1beta1
certificates.k8s.io/v1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
crd.projectcalico.org/v1
discovery.k8s.io/v1beta1
events.k8s.io/v1
events.k8s.io/v1beta1
extensions/v1beta1
metrics.k8s.io/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

标签在资源关联的用法：

标签选择器 selector
标签

项目	解释
apiVersion	API版本
kind	资源类型
metadata	资源元数据
spec	资源规格
replicas	副本数量
selector	标签选择器
template	Pod模板
metadata	Pod元数据
spec	Pod规格
containers	容器配置

3.2 服务编排：YAML文件格式说明

YAML 是一种简洁的非标记语言。

语法格式：

缩进表示层级关系
不支持制表符 “tab” 缩进，使用空格缩进
通常开头缩进 2 个空格
字符后缩进 1 个空格，如冒号、逗号等
“- - -” 表示YAML格式，一个文件的开始
“#” 注释

3.3 服务编排：资源字段太多，记不住怎么办

用create命令生成

kubectl create deployment nginx --image=nginx:1.16 -o yaml --dry-run=client > my-deploy.yaml

用get命令导出

kubectl get deployment nginx -o yaml > my-deploy.yaml

Pod容器的字段拼写忘记了

kubectl explain pods.spec.containers
kubectl explain deployment

-o, --output=’’: 输出指定的格式，常用的有json/yaml/name

[root@k8s-master ~]# kubectl create deployment nginx --image=nginx:1.16 -o yaml --dry-run=client
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx:1.16
        name: nginx
        resources: {}
status: {}

[root@k8s-master ~]# kubectl get deploy web -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
  creationTimestamp: "2021-11-22T03:30:03Z"
  generation: 1
  labels:
    app: web
  managedFields:
  - apiVersion: apps/v1
    fieldsType: FieldsV1
    fieldsV1:
      f:metadata:
        f:labels:
          .: {}
          f:app: {}
      f:spec:
        f:progressDeadlineSeconds: {}
        f:replicas: {}
        f:revisionHistoryLimit: {}
        f:selector:
          f:matchLabels:
            .: {}
            f:app: {}
        f:strategy:
          f:rollingUpdate:
            .: {}
            f:maxSurge: {}
            f:maxUnavailable: {}
          f:type: {}
        f:template:
          f:metadata:
            f:labels:
              .: {}
              f:app: {}
          f:spec:
            f:containers:
              k:{"name":"nginx"}:
                .: {}
                f:image: {}
                f:imagePullPolicy: {}
                f:name: {}
                f:resources: {}
                f:terminationMessagePath: {}
                f:terminationMessagePolicy: {}
            f:dnsPolicy: {}
            f:restartPolicy: {}
            f:schedulerName: {}
            f:securityContext: {}
            f:terminationGracePeriodSeconds: {}
    manager: kubectl-create
    operation: Update
    time: "2021-11-22T03:30:03Z"
  - apiVersion: apps/v1
    fieldsType: FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          .: {}
          f:deployment.kubernetes.io/revision: {}
      f:status:
        f:conditions:
          .: {}
          k:{"type":"Available"}:
            .: {}
            f:lastTransitionTime: {}
            f:lastUpdateTime: {}
            f:message: {}
            f:reason: {}
            f:status: {}
            f:type: {}
          k:{"type":"Progressing"}:
            .: {}
            f:lastTransitionTime: {}
            f:lastUpdateTime: {}
            f:message: {}
            f:reason: {}
            f:status: {}
            f:type: {}
        f:observedGeneration: {}
        f:replicas: {}
        f:unavailableReplicas: {}
        f:updatedReplicas: {}
    manager: kube-controller-manager
    operation: Update
    time: "2021-12-09T21:15:24Z"
  name: web
  namespace: default
  resourceVersion: "1568972"
  selfLink: /apis/apps/v1/namespaces/default/deployments/web
  uid: ba0bbdcc-5760-4dce-86af-7eb647156b68
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: web
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: web
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status:
  conditions:
  - lastTransitionTime: "2021-11-22T03:30:03Z"
    lastUpdateTime: "2021-11-22T03:30:28Z"
    message: ReplicaSet "web-96d5df5c8" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  - lastTransitionTime: "2021-12-09T21:15:24Z"
    lastUpdateTime: "2021-12-09T21:15:24Z"
    message: Deployment does not have minimum availability.
    reason: MinimumReplicasUnavailable
    status: "False"
    type: Available
  observedGeneration: 1
  replicas: 1
  unavailableReplicas: 1
  updatedReplicas: 1
[root@k8s-master ~]# kubectl get deploy web -o yaml > deploy2.yaml
[root@k8s-master ~]# vi deploy2.yaml
[root@k8s-master ~]# cat deploy2.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: web
  name: web
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: web
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx
        resources: {}
      dnsPolicy: ClusterFirst
      restartPolicy: Always

4. 应用升级、弹性收缩、回滚、删除

应用升级

kubectl set image deployment/web nginx=nginx:1.16
# 查看升级状态
kubectl rollout status deployment/web

[root@k8s-master ~]# kubectl set image deployment nginx-deployment nginx=nginx:1.16 
deployment.apps/nginx-deployment image updated
[root@k8s-master ~]# kubectl get pods -w
NAME                                READY   STATUS              RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running             4          14d
my-dep-5f8dfc8c78-f4ln4             1/1     Running             4          14d
my-dep-5f8dfc8c78-j9fqp             1/1     Running             4          14d
nginx-deployment-644599b9c9-96ng4   0/1     ContainerCreating   0          4s
nginx-deployment-644599b9c9-c47jg   1/1     Running             0          31s
nginx-deployment-7cf55fb7bb-d2t9n   1/1     Running             2          8d
nginx-deployment-7cf55fb7bb-gbtfr   1/1     Running             2          8d
nginx-deployment-7cf55fb7bb-npfqz   0/1     Terminating         2          8d
nginx-php                           1/1     Running             3          10d
web-96d5df5c8-ghb6g                 1/1     Running             4          17d
web2                                1/1     Running             3          10d
nginx-deployment-7cf55fb7bb-npfqz   0/1     Terminating         2          8d
nginx-deployment-7cf55fb7bb-npfqz   0/1     Terminating         2          8d
···
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          14d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          14d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          14d
nginx-deployment-644599b9c9-96ng4   1/1     Running   0          77s
nginx-deployment-644599b9c9-c47jg   1/1     Running   0          104s
nginx-deployment-644599b9c9-d45qx   1/1     Running   0          46s
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d

弹性伸缩

# 手动扩容
kubectl scale deployment web --replicas=10
# 自动水平扩容（注意Pod必须配置resource.request）
kubectl autoscale deployment web --min=3 --max=10 --cpu-percent=80
kubectl get hpa

[root@k8s-master ~]# kubectl scale deployment nginx-deployment --replicas=10
deployment.apps/nginx-deployment scaled
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS              RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running             4          14d
my-dep-5f8dfc8c78-f4ln4             1/1     Running             4          14d
my-dep-5f8dfc8c78-j9fqp             1/1     Running             4          14d
nginx-deployment-644599b9c9-2ffhg   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-2t5vn   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-8tbgl   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-96ng4   1/1     Running             0          2m45s
nginx-deployment-644599b9c9-c47jg   1/1     Running             0          3m12s
nginx-deployment-644599b9c9-d45qx   1/1     Running             0          2m14s
nginx-deployment-644599b9c9-dhjzm   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-pvpwm   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-xsr8k   0/1     ContainerCreating   0          2s
nginx-deployment-644599b9c9-zqskd   0/1     ContainerCreating   0          2s
nginx-php                           1/1     Running             3          10d
web-96d5df5c8-ghb6g                 1/1     Running             4          17d
web2                                1/1     Running             3          10d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          14d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          14d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          14d
nginx-deployment-644599b9c9-2ffhg   1/1     Running   0          82s
nginx-deployment-644599b9c9-2t5vn   1/1     Running   0          82s
nginx-deployment-644599b9c9-8tbgl   1/1     Running   0          82s
nginx-deployment-644599b9c9-96ng4   1/1     Running   0          4m5s
nginx-deployment-644599b9c9-c47jg   1/1     Running   0          4m32s
nginx-deployment-644599b9c9-d45qx   1/1     Running   0          3m34s
nginx-deployment-644599b9c9-dhjzm   1/1     Running   0          82s
nginx-deployment-644599b9c9-pvpwm   1/1     Running   0          82s
nginx-deployment-644599b9c9-xsr8k   1/1     Running   0          82s
nginx-deployment-644599b9c9-zqskd   1/1     Running   0          82s
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d

HPA：Pod水平扩容
kubectl top/hpa -> apiserver -> metrics-server -> kubelet -> pod
如果hpa出现unkunow：

kubectl top 正常否
deployment 是否配置 request
containers:
- name: nginx
  image: nginx:1.14.2
  ports:
  - containerPort: 80
    resources:
    requests:
    cpu: 0.5

[root@k8s-master ~]# kubectl get pods -n kube-system
NAME                                      READY   STATUS    RESTARTS   AGE
calico-kube-controllers-97769f7c7-z6npb   1/1     Running   4          18d
calico-node-4pwdc                         1/1     Running   4          18d
calico-node-9r6zd                         1/1     Running   4          18d
calico-node-vqzdj                         1/1     Running   4          18d
coredns-6d56c8448f-gcgrh                  1/1     Running   4          18d
coredns-6d56c8448f-tbsmv                  1/1     Running   4          18d
etcd-k8s-master                           1/1     Running   5          18d
kube-apiserver-k8s-master                 1/1     Running   11         18d
kube-controller-manager-k8s-master        1/1     Running   13         17d
kube-proxy-5qpgc                          1/1     Running   4          18d
kube-proxy-q2xfq                          1/1     Running   4          18d
kube-proxy-tvzpd                          1/1     Running   4          18d
kube-scheduler-k8s-master                 1/1     Running   15         17d
metrics-server-84f9866fdf-kt2nb           1/1     Running   4          10d
[root@k8s-master ~]# kubectl api-resources|grep hpa
horizontalpodautoscalers          hpa          autoscaling                    true         HorizontalPodAutoscaler

[root@k8s-master ~]# kubectl autoscale deployment nginx-deployment --min=3 --max=10 --cpu-percent=10
horizontalpodautoscaler.autoscaling/nginx-deployment autoscaled
[root@k8s-master ~]# kubectl get hpa
NAME               REFERENCE                     TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
nginx-deployment   Deployment/nginx-deployment   <unknown>/10%   3         10        10         40s
[root@k8s-master ~]# vi deployment.yaml 
[root@k8s-master ~]# cat deployment.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80
        resources:
          requests:
            cpu: 0.5
[root@k8s-master ~]# kubectl apply -f deployment.yaml 
deployment.apps/nginx-deployment configured
[root@k8s-master ~]# kubectl get hpa
NAME               REFERENCE                     TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
nginx-deployment   Deployment/nginx-deployment   0%/10%    3         10        3          8m28s

# 对项目压测
[root@k8s-node1 ~]# yum install httpd-tools
[root@k8s-node1 ~]# ab -n 100000 -c 1000 http://10.100.228.0/index.html
This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 10.100.228.0 (be patient)
Completed 10000 requests
Completed 20000 requests

[root@k8s-master ~]# kubectl top pod
NAME                                CPU(cores)   MEMORY(bytes)   
my-dep-5f8dfc8c78-dvxp8             3m           178Mi           
my-dep-5f8dfc8c78-f4ln4             2m           189Mi           
my-dep-5f8dfc8c78-j9fqp             2m           172Mi           
nginx-deployment-7f78c49b8f-6fnq2   246m         4Mi             
nginx-deployment-7f78c49b8f-ftzb7   395m         5Mi             
nginx-deployment-7f78c49b8f-tjldz   267m         2Mi             
nginx-php                           1m           14Mi            
web-96d5df5c8-ghb6g                 0m           3Mi             
web2                                1m           16Mi            
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          15d
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running   0          6m40s
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running   0          6m37s
nginx-deployment-7f78c49b8f-mjjkt   1/1     Running   0          10s
nginx-deployment-7f78c49b8f-mw5vb   1/1     Running   0          10s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running   0          6m35s
nginx-deployment-7f78c49b8f-tr7v6   1/1     Running   0          10s
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          15d
nginx-deployment-7f78c49b8f-4bnjn   0/1     Pending   0          22s
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running   0          7m8s
nginx-deployment-7f78c49b8f-cdqn6   0/1     Pending   0          22s
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running   0          7m5s
nginx-deployment-7f78c49b8f-mjjkt   1/1     Running   0          38s
nginx-deployment-7f78c49b8f-mw5vb   1/1     Running   0          38s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running   0          7m3s
nginx-deployment-7f78c49b8f-tr7v6   1/1     Running   0          38s
nginx-deployment-7f78c49b8f-ww7bw   0/1     Pending   0          22s
nginx-deployment-7f78c49b8f-z47qc   0/1     Pending   0          22s
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d

[root@k8s-master ~]# kubectl delete hpa nginx nginx-deployment
horizontalpodautoscaler.autoscaling "nginx-deployment" deleted
[root@k8s-master ~]# kubectl get hpa
No resources found in default namespace.
[root@k8s-master ~]# kubectl top hpa
error: unknown command "hpa"
See 'kubectl top -h' for help and examples
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          15d
nginx-deployment-7f78c49b8f-4bnjn   0/1     Pending   0          4m4s
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running   0          10m
nginx-deployment-7f78c49b8f-cdqn6   0/1     Pending   0          4m4s
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running   0          10m
nginx-deployment-7f78c49b8f-mjjkt   1/1     Running   0          4m20s
nginx-deployment-7f78c49b8f-mw5vb   1/1     Running   0          4m20s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running   0          10m
nginx-deployment-7f78c49b8f-tr7v6   1/1     Running   0          4m20s
nginx-deployment-7f78c49b8f-ww7bw   0/1     Pending   0          4m4s
nginx-deployment-7f78c49b8f-z47qc   0/1     Pending   0          4m4s
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d
[root@k8s-master ~]# kubectl scale deployment nginx-deployment --replicas=3
deployment.apps/nginx-deployment scaled
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS        RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running       4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running       4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running       4          15d
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-mjjkt   0/1     Terminating   0          5m14s
nginx-deployment-7f78c49b8f-mw5vb   0/1     Terminating   0          5m14s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-tr7v6   0/1     Terminating   0          5m14s
nginx-php                           1/1     Running       3          10d
web-96d5df5c8-ghb6g                 1/1     Running       4          17d
web2                                1/1     Running       3          10d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS        RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running       4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running       4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running       4          15d
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-mjjkt   0/1     Terminating   0          5m17s
nginx-deployment-7f78c49b8f-mw5vb   0/1     Terminating   0          5m17s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-tr7v6   0/1     Terminating   0          5m17s
nginx-php                           1/1     Running       3          10d
web-96d5df5c8-ghb6g                 1/1     Running       4          17d
web2                                1/1     Running       3          10d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS        RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running       4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running       4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running       4          15d
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-mjjkt   0/1     Terminating   0          5m21s
nginx-deployment-7f78c49b8f-mw5vb   0/1     Terminating   0          5m21s
nginx-deployment-7f78c49b8f-tjldz   1/1     Running       0          11m
nginx-deployment-7f78c49b8f-tr7v6   0/1     Terminating   0          5m21s
nginx-php                           1/1     Running       3          10d
web-96d5df5c8-ghb6g                 1/1     Running       4          17d
web2                                1/1     Running       3          10d
[root@k8s-master ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
my-dep-5f8dfc8c78-dvxp8             1/1     Running   4          15d
my-dep-5f8dfc8c78-f4ln4             1/1     Running   4          15d
my-dep-5f8dfc8c78-j9fqp             1/1     Running   4          15d
nginx-deployment-7f78c49b8f-6fnq2   1/1     Running   0          11m
nginx-deployment-7f78c49b8f-ftzb7   1/1     Running   0          11m
nginx-deployment-7f78c49b8f-tjldz   1/1     Running   0          11m
nginx-php                           1/1     Running   3          10d
web-96d5df5c8-ghb6g                 1/1     Running   4          17d
web2                                1/1     Running   3          10d

回滚

kubectl rollout history deployment/web
kubectl rollout undo deployment/web # 回滚上一个版本
kubectl rollout undo deployment/web --to-revision=2 # 回滚指定版本

[root@k8s-master ~]# kubectl rollout history deployment nginx-deployment
deployment.apps/nginx-deployment 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

--record参数将当前命令记录到发布记录里，方便知道回滚的镜像版本：
kubectl set image deployment nginx-deployment nginx=nginx:1.17 --record

删除

kubectl delete deploy/web
kubectl delete svc/web

5. 滚动升级与回滚实现机制

滚动更新策略
每次只升级一个或多个服务，升级完成加入生产环境，不断执行这个过程，直到集群中的全部旧版升级新版本。

特点：

用户无感知，平滑过渡

缺点：

部署周期长
发布策略较复杂

在这里插入图片描述

滚动更新在K8s中实现：

1个Deployment
2个ReplicaSet

[root@k8s-master ~]# kubectl get rs
NAME                          DESIRED   CURRENT   READY   AGE
my-dep-5f8dfc8c78             3         3         3       15d
nginx-deployment-644599b9c9   0         0         0       5h27m
nginx-deployment-7cf55fb7bb   0         0         0       8d
nginx-deployment-7f78c49b8f   3         3         3       5h8m
web-96d5df5c8                 1         1         1       17d

ReplicaSet：副本集

协助Deployment做事
Pod副本数量管理，不断对比当前Pod数量与期望Pod数量
Deployment每次发布都会创建一个RS作为记录，用于实现回滚

kubectl get rs #查看RS记录
kubectl rollout history deployment web #版本对应RS记录
在这里插入图片描述

6. Pod对象：Pod设计思想、应用自修复、Init container、静态Pod

6.1 Pod对象：基本概念

最小部署单元
一组容器的集合
一个Pod中的容器共享网络命名空间
Pod是短暂的

定义Pod：

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
  - name: container1
    image: nginx
    
  - name: container2
    image: centos

6.2 Pod对象：存在的意义

Pod为亲密性应用而存在。
亲密性应用场景：

两个应用之间发生文件交互
两个应用需要通过127.0.0.1或者socket通信（典型组合nginx+php）
两个应用需要发生频繁的调用

6.3 Pod对象：容器分类

Infrastructure Container：基础容器，维护整个Pod网络空间
InitContainers：初始化容器，先于业务容器开始执行
Containers：业务容器，并行启动

6.4 Pod对象：应用自恢复（重启策略+健康检查）

重启策略：

Always：当容器终止退出后，总是重启容器，默认策略。
OnFailure：当容器异常退出（退出状态码非0）时，才重启容器。
Never：当容器终止退出，从不重启容器。

健康检查有以下两种类型：

livenessProbe（存活检查）：如果检查失败，将杀死容器，根据Pod的restartPolicy来操作。
readinessProbe（就绪检查）：如果检查失败，Kubernetes会把Pod从service endpoints中剔除。

持久运行的程序，例如nginx、MySQL、jar
计划任务 cronjob
数据处理程序 job

if [ 1 == 2 ]; then
echo yes
exit 1
else
exit 0
fi

1、tcp端口探测
2、curl http://ip
3、ping检查服务器状态
4、端口是监听

支持以下三种检查方法：

httpGet：发送HTTP请求，返回200-400范围状态码为成功。
exec：执行Shell命令返回状态码是0为成功。
tcpSocket：发起TCP Socket建立成功。

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: web
  name: web
spec:
  replicas: 1
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      restartPolicy: Always
      containers:
      - image: lizhenliang/java-demo
        name: java-demo
        livenessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 30
          periodSeconds: 20

参考文档: https://kubernetes.io/docs/tasks/configure-pod-container/configureliveness-readiness-probes/

6.5 Pod对象：Init container

Init container：

基本支持所有普通容器特征
优先普通容器执行

应用场景：

控制普通容器启动，初始容器完成后才会启动业务容器
初始化配置，例如下载应用配置文件、注册信息等

apiVersion: v1
kind: Pod
metadata:
name: init-demo
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
volumeMounts:
- name: workdir
mountPath: /usr/share/nginx/html
initContainers:
- name: install
image: busybox
command:
- wget
- "-O"
- "/work-dir/index.html"
- http://kubernetes.io
volumeMounts:
- name: workdir
mountPath: "/work-dir"
dnsPolicy: Default
volumes:
- name: workdir
emptyDir: {}

6.6 Pod对象：静态Pod

静态Pod特点：

Pod由特定节点上的kubelet管理
不能使用控制器
Pod名称标识当前节点名称

在kubelet配置文件启用静态Pod：

vi /var/lib/kubelet/config.yaml
...
staticPodPath: /etc/kubernetes/manifests
...

将部署的pod yaml放到该目录会由kubelet自动创建

课后作业

1、在节点上配置kubelet托管启动一个pod

节点：k8s-node1
pod名称：web
镜像：nginx

# 检查是否启用
cat /var/lib/kubelet/config.yaml
staticPodPath: /etc/kubernetes/manifests

vi /etc/kubernetes/manifests/web.yaml
apiVersion: v1
kind: Pod
metadata:
  name: web
  namespace:
  labels:
    app: myapp
spec:
  containers:
  - name: nginx
    image: nginx
# 注：如果不生效，检查配置文件是否启用该功能

2、向pod中添加一个init容器，init容器创建一个空文件，如果该空文件没有被检测到pod退出

pod名称：web

apiVersion: v1
kind: Pod
metadata:
  name: web
spec:
  initContainers:
  - name: init
    image: nginx
    command:
    - touch
    - /opt/test
    volumeMounts:
    - name: data
      mountPath: /opt
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
  - name: data
    mountPath: /opt
  livenessProbe:
    exec:
      command:
      - cat
      - /opt/test
restartPolicy: Never
volumes:
- name: data
  emptyDir: {}

3、创建一个deployment 副本数 3，然后滚动更新镜像版本，并记录这个更新记录，最后再回滚到上一个版本

名称：nginx
镜像版本：1.16
更新镜像版本：1.17

kubectl create deployment web --image=nginx:1.16
kubectl set image deployment web nginx=nginx:1.17 --record
kubectl rollout history deploy web # 查看版本记录
kubectl rollout undo deployment web # 回滚到上一个版本
kubectl rollout undo deployment web --to-revision=1 # 也可以回滚到指定版本

4、给web deployment扩容副本数为3

kubectl scale deployment web --replicas=3

5、创建一个pod，其中运行着nginx、redis、memcached、consul 4个容器

apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers:
  - name: nginx
    image: nginx
  - name: redis
    image: redis
  - name: memcache
    image: memcached
  - name: consul
    image: consul

6、把deployment输出json文件，再删除创建的deployment

kubectl get deployments.apps web -o json > web.json
kubectl delete deployments.apps web

7、生成一个deployment yaml文件保存到/opt/deploy.yaml

名称：web
标签：app_env_stage=dev

kubectl create deployment web --image=nginx --dry-run=client -o yaml > /opt/deploy.yaml

# 再修改标签
apiVersion: apps/v1
kind: Deployment
metadata:
  name: java-demo
spec:
  replicas: 3
  selector:
    matchLabels:
      app_env_stage=dev
  template:
    metadata:
      labels:
        app_env_stage=dev
    spec:
      containers:
      - name: nginx
        image: nginx