ConfigMap概述
configmap用于将应用所需的配置信息与程序进行分离, 使应用程序更好的复用, 在大规模容器集群环境中, 对应用进行统一配置管理.
一般应用场景:
- 生成为容器内的环境变量;
- 以Volume的形式挂载为容器内部的文件或目录.
configmap以一个或多个key:value的形式保存在kubernetes系统中供应用使用, 既可以用于表示一个变量的值(例如log-level:info), 也可以用于表示一个完整的配置文件内容(例如xml或properties配置文件的全部内容).
声明方式:
- 使用yaml配置文件;
- 使用命令行命令(kubectl create configmap).
Pod中使用方式:
- 环境变量方式
- Volume挂载
创建ConfigMap
1. 使用yaml文件方式创建
1) 内容为变量
创建yaml文件cm-log-test.yaml:
apiVersion: v1
kind: ConfigMap
metadata:
name: cm-log
data:
apploglevel: info
appdatadir: /var/data生成configmap:
[root@localhost pod_dir]# kubectl create -f cm-log-test.yaml
configmap "cm-log" created2) 内容为配置文件内容
创建yaml文件cm-file-test.yaml:
apiVersion: v1
kind: ConfigMap
metadata:
name: cm-file
data:
key-serverxml: |
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
http://www.springframework.org/schema/task/spring-task.xsd">
<context:annotation-config />
<context:component-scan base-package="com.ysbd" />
<aop:aspectj-autoproxy proxy-target-class="true" />
<bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
<constructor-arg>
<bean class="com.zaxxer.hikari.HikariConfig">
<property name="poolName" value="HikariDataSource" />
<property name="driverClassName" value="${jdbc.driverClassName}" />
</bean>
</constructor-arg>
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<tx:advice id="transactionAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="*" propagation="REQUIRED" />
</tx:attributes>
</tx:advice>
<aop:config>
<aop:pointcut expression="execution(* com.ysbd.service..*.*(..))" id="allManagerMethod" />
<aop:advisor advice-ref="transactionAdvice" pointcut-ref="allManagerMethod" />
</aop:config>
</beans>
key-loggingproperties: |
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ku8manage?useUnicode=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=******
https=true
web.uri=http://localhost:8080
web.session.expireTime=1200生成configmap:
[root@localhost pod_dir]# kubectl create -f cm-file-test.yaml
configmap "cm-file" created2. 使用命令行方式创建
1) 字面值创建
使用--from-literal按字面值创建, 每个--from-literal后跟一个键值对.
# 语法
kubectl create configmap <cm-name> --from-literal=key1=value1 --from-literal=key2=value2[root@localhost pod_dir]# kubectl create configmap cm-literal --from-literal=loglevel=info --from-literal=datadir=/var/data
configmap "cm-literal" created验证
[root@localhost pod_dir]# kubectl get configmap cm-literal -o yaml
apiVersion: v1
data:
datadir: /var/data
loglevel: info
kind: ConfigMap
metadata:
creationTimestamp: 2018-07-05T11:29:55Z
name: cm-literal
namespace: default
resourceVersion: "29156"
selfLink: /api/v1/namespaces/default/configmaps/cm-literal
uid: bdfe61f9-8046-11e8-b599-000c2964ecfc2) 文件创建
使用--from-file按文件创建, 每个--from-file后跟一个文件路径, 也可以指定key名称, 可选.
# 语法
kubectl create configmap <cm-name> --from-file=[key=]file-path-1 --from-file=[key=]file-path-2[root@localhost pod_dir]# kubectl create configmap cm-file --from-file=./server.xml --from-file=./log.properties
configmap "cm-file" created验证
[root@localhost pod_dir]# kubectl describe configmaps cm-file
Name: cm-file
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
log.properties:
----
verClassName=com.mysql.jdbc.Driver...
server.xml:
----
ns xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance...3) 目录创建
使用--from-literal按字面值创建, --from-file后跟一个目录, 该目录下的每个配置文件名都会被设置为key, 文件的内容被设置为value.
# 语法
kubectl create configmap <cm-name> --from-file=config-file-dir[root@localhost pod_dir]# kubectl create configmap cm-dir --from-file=./config-dir/
configmap "cm-dir" created验证
[root@localhost pod_dir]# kubectl describe configmap cm-dir
Name: cm-dir
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
log.properties:
----
verClassName=com.mysql.jdbc.Driver...
server.xml:
----
ns xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance...在Pod中使用ConfigMap
1. 环境变量方式
以前面创建的创cm-log为例:
apiVersion: v1
kind: ConfigMap
metadata:
name: cm-log
data:
apploglevel: info
appdatadir: /var/data定义pod的yaml文件pod-cm-test.yaml:
apiVersion: v1
kind: Pod
metadata:
name: cm-test-pod
labels:
name: cm-pod-label
spec:
containers:
- name: cm-test
image: busybox
command: ["/bin/sh", "-c", "env | grep APP"]
env:
- name: APPLOGLEVEL #定义环境变量名称
valueFrom:
configMapKeyRef:
name: cm-log #环境变量的值取自cm-log
key: apploglevel #取key apploglevel对应的值
- name: APPDATADIR
valueFrom:
configMapKeyRef:
name: cm-log
key: appdatadir
restartPolicy: Never创建Pod:
[root@localhost pod_dir]# kubectl create -f pod-cm-test.yaml
pod "cm-test-pod" created验证:
[root@localhost pod_dir]# kubectl logs cm-test-pod
APPDATADIR=/var/data
APPLOGLEVEL=info上面用到了valueFrom, 用于指定单个环境变量情况, 还有envFrom, 可以将指定ConfigMap中的所有键值自动生成环境变量, 环境变量名称就是key, 环境变量的值就是value. 如下:
apiVersion: v1
kind: Pod
metadata:
name: cm-test-pod
labels:
name: cm-pod-label
spec:
containers:
- name: cm-test
image: busybox
command: ["/bin/sh", "-c", "env"]
envFrom:
- configMapRef:
name: cm-log
restartPolicy: Never创建Pod:
[root@localhost pod_dir]# kubectl create -f pod-test-envFrom.yaml
pod "cm-test-pod" created验证:
[root@localhost pod_dir]# kubectl logs cm-test-pod
apploglevel=info
KUBERNETES_PORT=tcp://10.68.0.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
appdatadir=/var/data
KUBERNETES_PORT_443_TCP=tcp://10.68.0.1:443
PWD=/2. Volume挂载
使用上边以cm-file-test.yaml创建的cm-file为例.
创建Pod:
apiVersion: v1
kind: Pod
metadata:
name: cm-test-volume
spec:
containers:
- name: cm-test-volume
image: kubeguide/tomcat-app:v1
ports:
- containerPort: 8080
volumeMounts:
- name: server
mountPath: /configfiles
volumes:
- name: server
configMap:
name: cm-file
items:
- key: key-serverxml
path: server.xml
- key: key-properties
path: logging.properties创建Pod:
[root@localhost pod_dir]# kubectl create -f pod-volume-test.yaml
pod "cm-test-volume" created验证:
登录容器, 查看configfiles目录下存在server.xml和logging.properties文件:
[root@localhost pod_dir]# kubectl exec -ti cm-test-volume -- bash
root@cm-test-volume:/usr/local/tomcat# cd /configfiles/
root@cm-test-volume:/configfiles# ls -a
. .. ..2018_07_05_13_14_04.531049961 ..data logging.properties server.xml查看文件内容:
root@cm-test-volume:/configfiles# cat logging.properties
verClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ku8manage?useUnicode=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai
...
root@cm-test-volume:/configfiles# cat logging.properties
verClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ku8manage?useUnicode=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=******
https=true
web.uri=http://localhost:8080
web.session.expireTime=1200
root@cm-test-volume:/configfiles# cat server.xml
ns xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
http://www.springframework.org/schema/task/spring-task.xsd">
...如果在引用ConfigMap时不指定items, 则使用volumeMount方式在容器内的目录中为每个item生成一个文件名为key的文件, 如下:
创建Pod:
apiVersion: v1
kind: Pod
metadata:
name: cm-test-volume
spec:
containers:
- name: cm-test-volume
image: kubeguide/tomcat-app:v1
ports:
- containerPort: 8080
volumeMounts:
- name: server
mountPath: /configfiles
volumes:
- name: server
configMap:
name: cm-file应用: 使用ConfigMap配置redis
创建ConfigMap:
[root@localhost pod_dir]# kubectl create configmap example-redis-config --from-file=./redis-config
configmap "example-redis-config" createdredis-config文件内容如下:
maxmemory 2mb
maxmemory-policy allkeys-lru查看已创建的配置ConfigMap:
[root@localhost pod_dir]# kubectl get configmap example-redis-config -o yaml
apiVersion: v1
data:
redis-config: |
maxmemory 2mb
maxmemory-policy allkeys-lru
kind: ConfigMap
metadata:
creationTimestamp: 2018-07-06T02:03:56Z
name: example-redis-config
namespace: default
resourceVersion: "41583"
selfLink: /api/v1/namespaces/default/configmaps/example-redis-config
uid: d6fa0d84-80c0-11e8-b599-000c2964ecfc创建pod yaml文件:
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: kubernetes/redis:v1
env:
- name: MASTER
value: "true"
ports:
- containerPort: 6379
resources:
limits:
cpu: "0.1"
volumeMounts:
- mountPath: /redis-master-data
name: data
- mountPath: /redis-master
name: config
volumes:
- name: data
emptyDir: {}
- name: config
configMap:
name: example-redis-config
items:
- key: redis-config
path: redis.conf创建pod:
[root@localhost pod_dir]# kubectl create -f pod-cm-redis-test.yaml
pod "redis" created验证:
进入容器查看
[root@localhost pod_dir]# kubectl exec -it redis redis-cli
127.0.0.1:6379> CONFIG GET maxmemory
1) "maxmemory"
2) "2097152"
127.0.0.1:6379> config get maxmemory-policy
1) "maxmemory-policy"
2) "allkeys-lru"使用ConfigMap须知:
- ConfigMap必须在pod创建之前创建;
- ConfigMap受Namespace限制, 处于同一Namespace的pod才能引用到它;
- kubelet只支持被API server管理的pod使用ConfigMap, 也就是说静态pod不能使用ConfigMap.
