Pod容器共享 Volume

项目背景

在下面示例中，Pod内包含两个容器：tomcat 和 busybox ,在 Pod 级别设置 Volume "app-logs"，用于 tomcat 向其中写入日志文件，busybox 读日志文件。

# cat pod-volume-applogs.yaml apiVersion: v1kind: Podmetadata:  name: volume-podspec:  containers:  - name: tomcat   image: tomcat   ports:   - containerPort: 8080   volumeMounts:   - name: app-logs     mountPath: /usr/local/tomcat/logs  - name: busybox   image: busybox   command: ["sh","-c","tail -f /logs/catalina*.log"]   volumeMounts:   - name: app-logs     mountPath: /logs  volumes:  - name: app-logs   emptyDir: {}

这里设置的 Volume 名为 app-logs，类型为 emptyDir(也可以设置为其他类型)，挂载到 tomcat 容器内的 /usr/local/tomcat/logs 目录，同时挂载到 logreader 容器内的 /logs 目录。tomcat 容器会在启动后会向 /usr/log/tomcat/logs 目录中写文件，logreader 容器就可以读取其中的文件了。

可以通过 kubectl logs 命令查看 logreader 容器的输出内容：

# find / -name app-logs[root@master other]# kubectl logs volume-pod -c busybox26-Jul-2019 18:06:22.126 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.webresources26-Jul-2019 18:06:22.126 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dorg.apache.catalina.security.SecurityListener.UMASK=002726-Jul-2019 18:06:22.144 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dignore.endorsed.dirs=26-Jul-2019 18:06:22.144 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.base=/usr/local/tomcat26-Jul-2019 18:06:22.144 INFO [main] ......

登录 tomcat 容器进行查看：

# kubectl exec -it volume-pod -c tomcat -- ls /usr/local/tomcat/logscatalina.2019-07-26.log     localhost_access_log.2019-07-26.txthost-manager.2019-07-26.log  manager.2019-07-26.loglocalhost.2019-07-26.log# kubectl exec -it volume-pod -c tomcat -- tail /usr/local/tomcat/logs/catalina.2019-07-26.log26-Jul-2019 18:06:29.935 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/usr/local/tomcat/webapps/docs] has finished in [388] ms26-Jul-2019 18:06:29.936 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/usr/local/tomcat/webapps/examples]26-Jul-2019 18:06:32.777 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/usr/local/tomcat