Kubernetes存储之ConfigMap
Posted Yuan_sr
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ConfigMap功能在Kubernetes1.2版本中引入,许多应用程序会从配置文件,命令行参数或环境变量中读取配置信息,ConfigMap API给我们提供了向容器中注入配置信息的机制,ConfigMap可以被用来保存单个属性,也可以用来保存整个配置文件或者JSON二进制对象
ConfigMap的创建
1.使用目录创建
$ ls docs/user-guide/configmap/kubectl/
game.properties
ui.properties
$ cat docs/user-guide/configmap/kubectl/game.properties
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
enemies.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
$ cat docs/user-guide/configmap/kubectl/ui.properties
color.good=purple
color.bad=yellow
aoolw.textmode=true
how.nice.to.look=fairlyNice
$ kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl
--from-file
指定在目录下的所有文件都会被用在ConfigMap里面创建一个键值对,键的名字就是文件名,值就是文件的内容
2.使用文件创建
$ kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl/game.properties
$ kubectl get configmaps game-config -o yaml
3.使用字面值创建
使用文字值创建,利用--from-literal
参数传递配置信息,该参数可以使用多次,格式如下:
$ kubectl create configmap special-config --from-literal=special.how --from-literal=special.type=charm
$ kubectl get configmaps special-config -o yaml
Pod中使用ConfigMap
- 使用ConfigMap来替代环境变量
apiVersion: v1
kind: ConfigMap
metadata:
name :special-config
namespace: default
data:
special.how: very
special.type.charm
apiVersion: v1
kind: ConfigMap
metadata:
name: env-config
namespace: default
data:
log_level: INFO
apiVersion: v1
kind: Pod
metadata:
name: dapi-test-pod
spec:
containers:
- name: test-container
image: myapp:v1
command: ["/bin/sh","-c","env"]
env:
- name: SPECIAL_LEVEL_KEY
calueFrom:
configMapKeyRef:
name: special-config
key: special.how
- name: SPECIAL_TYPE_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.type
envFrom:
- configMapRef:
name: env-config
restartPolicy: Never
- 用ConfigMap设置命令行参数
apiVersion: v1
kind: ConfigMap
metadata:
name: special-config
namespace: default
data:
special.how: very
special.type: charm
apiVersion: v1
kind: Pod
metadata:
name: dapi-test-pod
spec:
containers:
- name: test-container
image: myapp:v1
command: ["/bin/sh", "-c", "echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)"]
env:
- name: SPECIAL_LEVEL_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.how
- name: SPECIAL_TYPE_KEY
calueFrom:
configMapKeyRef:
name: special-config
key: special.type
restartPolicy: Never
- 通过数据卷插件使用ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
name: special-config
namespace: dafault
data:
special.how: very
special.type: charm
在数据卷里面使用这个ConfigMap,有不同的选项,最基本的就是将文件填入数据卷,在这个文件中,键就是文件名,值就是文件内容
apiVersion: v1
kind: Pod
metadata:
name: dapi-test-pod
spec:
containers:
- name: test-container
image: myapp:v1
command: ["/bin/sh","-c","cat /etc/config/special.how"]
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: special-config
restartPolicy: Never
ConfigMap的热更新
apiVersion: v1
kind: ConfigMap
metadata:
name: log-config
namespace: default
data:
log_level: INFO
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 1
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: myapp:v1
ports:
- containerPort: 80
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: log-config
$ kubectl exec \'kubectl get pods -l run-my-nginx -o=name | cut -d "/" -f2\' --it -- cat /etc/config/log_level
INFO
修改ConfigMap
$ kubectl edit configmap log-config
修改log_level
的值为DEBUG
等待大约10秒,再次查看环境变量的值
$ kubectl exec \'kubectl get pods -l run-my-nginx -o=name | cut -d "/" -f2\' --it -- cat /etc/config/log_level
DEBUG
注意: ConfigMap如果以ENV的方式挂载至容器,修改ConfigMap并不会实现热更新
ConfigMap更新后滚动更新Pod
更新ConfigMap目前并不会触发相关Pod的滚动更新,可以通过修改pod annotations的方式强制触发滚动更新
$ kubectl patch deployment my-nginx --patch \'{"spec": {"template": {"metadata": {"annotations":{"version/config": "20210516"}}}}}\'
更新ConfigMap后:
- 使用该ConfigMap挂载的ENV不会同步更新
- 使用该ConfigMap挂载的Volume中的数据需要一段时间(10s)才能同步更新
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