Docker (20)--Docker k8s--Kubernetes storage--Configmap configuration management

1. Clean up the environment

##删除namespace
[root@server2 ingress]# kubectl get ns   ##查看所有namespace，并删除
[root@server2 ingress]# kubectl delete pod --all -n demo --force ##先删除里面pod在删除ns会快一点
[root@server2 ingress]# kubectl delete ns demo 
##删除pod
[root@server2 ingress]# kubectl delete pod --all -n test --force 
[root@server2 ingress]# kubectl delete ns test 
[root@server2 ingress]# kubectl delete pod nginx --force 
[root@server2 ingress]# kubectl delete deployments.apps deployment
[root@server2 ingress]# kubectl delete pod demo --force 
##删除服务
[root@server2 ingress]# kubectl get svc
[root@server2 ingress]# kubectl delete svc nginx-svc 
##删除ingress服务
[root@server2 ingress]# kubectl delete ingress ingress-demo 

## 删除网络策略
[root@server2 ingress]# kubectl delete networkpolicies. --all

2. Configmap configuration management

- 	Configmap用于保存配置数据，以键值对形式存储。
	configMap 资源提供了向 Pod 注入配置数据的方法。
	旨在让镜像和配置文件解耦，以便实现镜像的可移植性和可复用性。	
	典型的使用场景：	
		1.填充环境变量的值
		2.设置容器内的命令行参数
		3.填充卷的配置文件     ##使用较多


- 创建ConfigMap的方式有4种：
	1.使用字面值创建
	2.使用文件创建
	3.使用目录创建
	4.编写configmap的yaml文件创建
	
- 1.使用字面值创建
	$ kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2

- 2.使用文件创建	 
	$ kubectl create configmap my-config-2 --from-file=/etc/resolv.conf
	key的名称是文件名称，value的值是这个文件的内容

- 3.使用目录创建
	$ kubectl create configmap my-config-3 --from-file=test
	目录中的文件名为key，文件内容是value

- 4.编写configmap的yaml文件
	$ vim cm1.yaml
	apiVersion: v1
	kind: ConfigMap
	metadata:
	  name: cm1-config
	data:
	  db_host: "172.25.0.250"
	  db_port: "3306"
	
	$ kubectl create -f cm1.yaml

2.1 Create with literal values

[root@server2 ingress]# kubectl get cm
[root@server2 ~]# kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2
[root@server2 ~]# kubectl describe cm my-config 

2.2. Use file creation

[root@server2 ~]# kubectl create configmap my-config-2 --from-file=/etc/resolv.conf

[root@server2 ~]# kubectl describe cm my-config-2 

2.3 3. Use directory creation

[root@server2 ~]# mkdir congfigmap
[root@server2 ~]# cd congfigmap/
[root@server2 congfigmap]# mkdir test
[root@server2 congfigmap]# cp /etc/resolv.conf test/
[root@server2 congfigmap]# ll test/
total 4
-rw-r--r-- 1 root root 28 Feb 24 16:16 resolv.conf
[root@server2 congfigmap]# kubectl create configmap my-config-3 --from-file=test

[root@server2 congfigmap]# kubectl describe cm my-config-3

2.4. Write the yaml file of configmap

[root@server2 congfigmap]# vim cm1.yaml 
[root@server2 congfigmap]# cat cm1.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: cm1-config
data:
  db_host: "172.25.13.250"
  db_port: "3306"

[root@server2 congfigmap]# kubectl apply -f cm1.yaml    ##应用
[root@server2 congfigmap]# kubectl describe cm cm1-config    ##描述详细信息

3. How to use configmap

- 如何使用configmap：
	1.通过环境变量的方式直接传递给pod		
	2.通过在pod的命令行下运行的方式		
	3.作为volume的方式挂载到pod内     ##此方式最常用

3.1 Use configmap to set environment variables

[root@server2 congfigmap]# vim pod1.yaml
[root@server2 congfigmap]# cat pod1.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod1
spec:
  containers:
    - name: pod1
      image: busyboxplus
      command: ["/bin/sh", "-c", "env"]
      env:
        - name: key1
          valueFrom:
            configMapKeyRef:
              name: cm1-config
              key: db_host
        - name: key2
          valueFrom:
            configMapKeyRef:
              name: cm1-config
              key: db_port
  restartPolicy: Never
[root@server2 congfigmap]# kubectl apply -f pod1.yaml 
[root@server2 congfigmap]# kubectl get pod
NAME   READY   STATUS      RESTARTS   AGE
pod1   0/1     Completed   0          8s
[root@server2 congfigmap]# kubectl logs pod1    ##查看日志是否有cm1-config信息
key1=172.25.13.250
key2=3306

3.2 Use conigmap to set command line parameters

[root@server2 congfigmap]# 
[root@server2 congfigmap]# vim pod2.yaml
[root@server2 congfigmap]# cat pod2.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod2
spec:
  containers:
    - name: pod2
      image: busyboxplus
      command: ["/bin/sh", "-c", "echo $(db_host) $(db_port)"]
      envFrom:
        - configMapRef:
            name: cm1-config
  restartPolicy: Never
[root@server2 congfigmap]# kubectl apply -f pod2.yaml 
pod/pod2 created
[root@server2 congfigmap]# kubectl get pod
NAME   READY   STATUS      RESTARTS   AGE
pod1   0/1     Completed   0          4m9s
pod2   0/1     Completed   0          9s
[root@server2 congfigmap]# kubectl logs pod2
172.25.13.250 3306

3.3 Use configmap through data volume

[root@server2 congfigmap]# kubectl apply -f pod2.yaml 
pod/pod2 created
[root@server2 congfigmap]# cat pod2.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod2
spec:
  containers:
    - name: pod2
      image: busyboxplus
      command: ["/bin/sh", "-c", "cat /config/db_host"]
      volumeMounts:
      - name: config-volume
        mountPath: /config
  volumes:
    - name: config-volume
      configMap:
        name: cm1-config
  restartPolicy: Never
[root@server2 congfigmap]# kubectl get pod
NAME   READY   STATUS      RESTARTS   AGE
pod1   0/1     Completed   0          15m
pod2   0/1     Completed   0          36s
pod3   1/1     Running     0          8m2s
[root@server2 congfigmap]# kubectl logs pod2 
172.25.13.250[root@server2 congfigmap]# 

3.4 Hot update of configmap (using data volume)

## 1. 配置并查看数据卷内容
[root@server2 congfigmap]# vim pod3.yaml 
[root@server2 congfigmap]# cat pod3.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod3
spec:
  containers:
    - name: pod3
      image: busyboxplus
      stdin: true
      tty: true
      volumeMounts:
      - name: config-volume
        mountPath: /config
  volumes:
    - name: config-volume
      configMap:
        name: cm1-config
[root@server2 congfigmap]# kubectl apply -f pod3.yaml 
[root@server2 congfigmap]# kubectl get pod
[root@server2 congfigmap]# kubectl attach pod3 -it    ##进入pod3并查看数据卷内容
/ # cd /config/
/config # cat *
172.25.13.2503306/config # 


## 2. 准备热更新
[root@server2 congfigmap]# kubectl edit cm cm1-config ##编辑文件内容
[root@server2 congfigmap]# kubectl get pod    #查看pod3是否运行

[root@server2 congfigmap]# kubectl attach pod3 -it 
/ # cd /config/
/config # cat *
172.25.13.1008080/config #   ##内容更新成功

## 1. Configure and view data volume content

## 2. Prepare for hot update

3.5 Pod rolling update

- configmap热更新后，并不会触发相关Pod的滚动更新，需要手动触发

[root@server2 congfigmap]# vim demo.yaml
[root@server2 congfigmap]# cat demo.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:v1
        volumeMounts:
        - name: config-volume
          mountPath: /etc/nginx/conf.d
      volumes:
        - name: config-volume
          configMap:
            name: nginx-config

[root@server2 congfigmap]# vim www.conf
[root@server2 congfigmap]# cat www.conf 
server {
    
    
    listen       8080;      ##此处自己书写的测试文件端口是8080
    server_name  _;

    location / {
    
    
        root /usr/share/nginx/html;
        index  index.html index.htm;
    }
}
[root@server2 congfigmap]# mv www.conf default.conf

[root@server2 congfigmap]# kubectl create configmap nginx-config --from-file=default.conf   ##创建cm
[root@server2 congfigmap]# kubectl get cm
[root@server2 congfigmap]# kubectl describe cm nginx-config 


[root@server2 congfigmap]# kubectl apply -f demo.yaml     ##创建pod
[root@server2 congfigmap]# kubectl get pod
NAME                    READY   STATUS    RESTARTS   AGE
demo-75679c99b4-cq52d   1/1     Running   0          9s
[root@server2 congfigmap]# kubectl describe pod demo-75679c99b4-cq52d    ##查看pod的详细信息


[root@server2 congfigmap]# kubectl  get pod -o wide    ##查看pod详细信息
NAME                    READY   STATUS    RESTARTS   AGE     IP               NODE      NOMINATED NODE   READINESS GATES
demo-75679c99b4-cq52d   1/1     Running   0          3m52s   10.244.141.198   server3   <none>           <none>
[root@server2 congfigmap]# curl 10.244.141.198    ##默认80端口是访问不到的
curl: (7) Failed connect to 10.244.141.198:80; Connection refused
[root@server2 congfigmap]# curl 10.244.141.198:8080   ##使用8080端口访问成功
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
[root@server2 congfigmap]# kubectl exec -it demo-75679c99b4-cq52d -- sh   ##进入终端查看nginx的默认conf文件

3.5.1 Two ways of pod rolling update

3.5.1.1 Update using commands (patching)

[root@server2 congfigmap]# kubectl edit cm nginx-config    ##编辑文件，修改端口号
[root@server2 congfigmap]# kubectl describe cm nginx-config  ##查看热更新是否成功
[root@server2 congfigmap]# curl 10.244.141.198:8080   ##发现更新成功后还是只能使用8080进行访问，这是因为pod没有更新
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>


[root@server2 congfigmap]# kubectl exec -it demo-75679c99b4-cq52d -- sh
/ # cat /etc/nginx/conf.d/default.conf    ##查看配置文件是否是热更新
server {
    
    
    listen       80;
    server_name  _;

    location / {
    
    
        root /usr/share/nginx/html;
        index  index.html index.htm;
    }
}
/ # netstat -antlp        ##查看端口发现还是8080

##实现pod滚动更新
[root@server2 congfigmap]# kubectl patch deployments.apps demo --patch '{"spec": {"template": {"metadata": {"annotations": {"version/config": "2021022401"}}}}}'  ##打补丁

[root@server2 congfigmap]# kubectl get pod
NAME                    READY   STATUS    RESTARTS   AGE
demo-7f476857fb-8xsmz   1/1     Running   0          8s

[root@server2 congfigmap]# kubectl get pod -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
demo-7f476857fb-8xsmz   1/1     Running   0          55s   10.244.22.5   server4   <none>           <none>
[root@server2 congfigmap]# curl 10.244.22.5
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

3.5.1.2 Delete pod update directly

- 适用于有控制器的pod

[root@server2 congfigmap]# kubectl edit cm nginx-config    ##把端口在改成8080
[root@server2 congfigmap]# kubectl edit cm nginx-config 
[root@server2 congfigmap]# kubectl get pod
NAME                    READY   STATUS    RESTARTS   AGE
demo-7f476857fb-8xsmz   1/1     Running   0          6m44s
[root@server2 congfigmap]# kubectl delete pod demo-7f476857fb-8xsmz 

[root@server2 congfigmap]# kubectl get pod -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP               NODE      NOMINATED NODE   READINESS GATES
demo-7f476857fb-w7wbs   1/1     Running   0          77s   10.244.141.199   server3   <none>           <none>
[root@server2 congfigmap]# curl 10.244.141.199:8080
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>