logging - Kubernetes Pod日志的绝对路径是什么？

Question

kubernetes pod日志的绝对路径是什么？
当我尝试kubectl logs pod时，我可以看到pod的日志。我想知道正在运行的pod的日志文件路径。

kubectl日志npapp-0r9jw

output: rectory /hab/pkgs/core/tomcat8/8.5.9/20170514144202/tc/webapps/ROOT has finished in 21 ms
national-parks.default(O): 22-Oct-2017 05:33:54.526 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /hab/pkgs/core/tomcat8/8.5.9/20170514144202/tc/webapps/manager
national-parks.default(O): 22-Oct-2017 05:33:54.564 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /hab/pkgs/core/tomcat8/8.5.9/20170514144202/tc/webapps/manager has finished in 38 ms
national-parks.default(O): 22-Oct-2017 05:33:54.564 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /hab/pkgs/core/tomcat8/8.5.9/20170514144202/tc/webapps/host-manager
national-parks.default(O): 22-Oct-2017 05:33:54.595 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /hab/pkgs/core/tomcat8/8.5.9/20170514144202/tc/webapps/host-manager has finished in 31 ms
national-parks.default(O): 22-Oct-2017 05:33:54.599 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler [http-nio-8080]
national-parks.default(O): 22-Oct-2017 05:33:54.613 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler [ajp-nio-8009]
national-parks.default(O): 22-Oct-2017 05:33:54.620 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 2735 ms

在哪里可以看到绝对日志文件路径？

Answer 1

如果查看Kubernetes sources，将会看到 pkg/routes/logs.go ，它将(默认情况下)提供/var/log中的文件内容(提供静态文件following this example)

func logFileHandler(req *restful.Request, resp *restful.Response) {
    logdir := "/var/log"
    actual := path.Join(logdir, req.PathParameter("logpath"))
    http.ServeFile(resp.ResponseWriter, req.Request, actual)
}

如您在kubernetes/kubernetes issue 53022中看到的:

The current symlink /var/log/containers is pointing to /var/log/pods/pod_UID/*.logs

因此，日志的完整绝对路径为:

/var/log/pods/pod_UID/*.logs

更新2019:

此问题也涉及analytics-platform-helm-charts PR 91:

Symlink /var/log/containers has been deprecated in favor of /var/log/pods for our version of the docker daemon for kubernetes metadata.

参见Kubernetes CRI(2018年11月)

Kubelet will be configured with a root directory (e.g., /var/log/pods or /var/lib/kubelet/logs/) to store all container logs. Below is an example of a path to the log of a container in a pod.

/var/log/pods/<podUID>/<containerName>_<instance#>.log

In CRI, this is implemented by setting the pod-level log directory when creating the pod sandbox, and passing the relative container log path when creating a container.

PodSandboxConfig.LogDirectory: /var/log/pods/<podUID>/
ContainerConfig.LogPath: <containerName>_<instance#>.log