kubenates 重要定义

Configmap

ConfigMap用于保存配置数据的键值对,可以用来保存单个属性,也可以用来保存配置文件

查看命令

查看列表:

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kubectl get configmap
or
kubectl get cm

查看详情:

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$> kubectl describe cm <configMapName>

创建命令

直接创建命令:

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$> kubectl create configmap <configMapName> 
--from-literal=nginx_port=80
--from-literal=server_name=k8s.zhaoweiguo.com
configmap/<configMapName> created

通过文件创建命令:

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$> cat cm.conf
server {
server_name k8s.zhaoweiguo.com;
listen 80;
root /var/www/;
}
$> kubectl create configmap <configMapName> --from-file=./cm.conf

使用ConfigMap-环境变量

配置文件:

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apiVersion: v1
kind: Pod
metadata:
name: configmap-pod
labels:
app: configmap
spec:
containers:
- name: configmap
image: alpine:v1
env:
- name: NGINX_SERVER_PORT
valueFrom:
configMapKeyRef:
name: <configMapName>
key: nginx_port
- name: NGINX_SERVER_NAME
valueFrom:
configMapKeyRef:
name: <configMapName>
key: server_name

生成pod并验证configmap的使用:

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$> kubectl apply -f pod.yaml
pod/configmap-pod created
$> kubectl get pods
NAME READY STATUS RESTARTS AGE
configmap-pod 1/1 Running 0 41s
// 查询内部变量
$> kubectl exec -it pod-cm-1 -- printenv |grep NGINX_SERVER
NGINX_SERVER_PORT=80
NGINX_SERVER_NAME=k8s.zhaoweiguo.com

修改configmap的内容看环境变量是否同步生效:

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$> kubectl edit cm nginx-config
// 把端口号nginx_port改为8888
$> kubectl describe cm nginx-config
// 查看configmap内容已经修改
$> kubectl exec -it pod-cm-1 -- printenv |grep NGINX_SERVER
NGINX_SERVER_PORT=80
NGINX_SERVER_NAME=k8s.zhaoweiguo.com
// 但环境变量的值并没有被修改
// 环境变量的值要在Pod重启后才会生效

使用ConfigMap-存储卷

配置文件:

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apiVersion: v1
kind: Pod
metadata:
name: configmap-pod
labels:
app: configmap
spec:
containers:
- name: myapp
image: alpine:v1
volumeMounts:
- name: nginxconf
mountPath: /etc/conf.d/
readOnly: true
volumes:
- name: nginxconf
configMap:
name: <configMapName>

验证configmap的使用:

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$> kubectl exec -it pod-cm-2 -- /bin/sh
$> ls /etc/conf.d/
nginx_port server_name
$> cat /etc/conf.d/nginx_port
80
$> cat /etc/conf.d/server_name
k8s.zhaoweiguo.com

修改configmap的内容看Volumn是否同步生效:

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$> kubectl edit cm nginx-config
// 把端口号nginx_port改为8888
$> kubectl describe cm nginx-config
// 查看configmap内容已经修改
$> cat /etc/conf.d/nginx_port
8888
// Volumn方式文件内容已经自动变化