Pod containers share Volume
Project background
In the following example, Pod contains two containers: tomcat and busybox, which sets Volume "app-logs" at the Pod level for tomcat to write log files to and busybox to read log files.
# 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: {}
The Volume set here is named app-logs and the type is emptyDir (you can also set it to other types). It is mounted to the / usr/local/tomcat/logs directory in the tomcat container and to the / logs directory in the logreader container. The tomcat container writes files to the / usr/log/tomcat/logs directory after startup, and the logreader container can read the files in it.
You can view the output of the logreader container through the kubectl logs command:
# find /-name app-logs [root@master other] # kubectl logs volume-pod-c busybox26-Jul-2019 1815 06root@master other 22.126 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument:-Djava.protocol.handler.pkgs=org.apache.catalina.webresources26-Jul-2019 18perimeter 06purl 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 org.apache.catalina.startup.VersionLoggerListener.log Command line argument 22.144 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument:-Dcatalina.base=/usr/local/tomcat26-Jul-2019 18 org.apache.catalina.startup.VersionLoggerListener.log Command line argument 06 org.apache.catalina.startup.VersionLoggerListener.log Command line argument 22.144 INFO [main].
Log in to the tomcat container to view:
# kubectl exec-it volume-pod-c tomcat-- ls / usr/local/tomcat/logscatalina.2019-07-26.loglocalhost _ 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 Fran 06Fran 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 ms26-Jul-2019 06lac 29.936 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/ usr/local/tomcat/webapps/examples] 26-Jul-2019 18Part 06Rd 32.777 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/ usr/local/tomcat
