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: v1
kind: Pod
metadata:
name: volume-pod
spec:
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 busybox 26-Jul-2019 18:06:22.126 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.w ebresources26-Jul-2019 18:06:22.126 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dorg.apache.catalina.security.SecurityListener.UM ASK=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/tomcat 26-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/logs catalina.2019-07-26.log localhost_access_log.2019-07-26.txt host-manager.2019-07-26.log manager.2019-07-26.log localhost.2019-07-26.log # kubectl exec -it volume-pod -c tomcat -- tail /usr/local/tomcat/logs/catalina.2019-07-26.log 26-Jul-2019 18:06:29.935 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/usr/local/tom cat/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
