Merge pull request #1821 from enisoc/debug-init-containers

Task: Debugging Init Containers

_data/tasks.yml

@@ -49,3 +49,8 @@ toc:
     path: /docs/tasks/manage-stateful-set/debugging-a-statefulset/
   - title: Force Deleting StatefulSet Pods
     path: /docs/tasks/manage-stateful-set/delete-pods/
+
+- title: Troubleshooting
+  section:
+  - title: Debugging Init Containers
+    path: /docs/tasks/troubleshoot/debug-init-containers/

docs/tasks/index.md

@@ -37,6 +37,10 @@ single thing, typically by giving a short sequence of steps.
 * [Debugging a StatefulSet](/docs/tasks/manage-stateful-set/debugging-a-statefulset/)
 * [Force Deleting StatefulSet Pods](/docs/tasks/manage-stateful-set/delete-pods/)
 
+#### Troubleshooting
+
+* [Debugging Init Containers](/docs/tasks/troubleshoot/debug-init-containers/)
+
 ### What's next
 
 If you would like to write a task page, see

docs/tasks/troubleshoot/debug-init-containers.md

@@ -0,0 +1,137 @@
+---
+assignees:
+- bprashanth
+- enisoc
+- erictune
+- foxish
+- janetkuo
+- kow3ns
+- smarterclayton
+
+---
+
+{% capture overview %}
+
+This page shows how to investigate problems related to the execution of
+Init Containers.
+
+{% endcapture %}
+
+{% capture prerequisites %}
+
+* You should be familiar with the basics of
+  [Init Containers](/docs/user-guide/pods/init-containers/).
+* You should have a [Pod](/docs/user-guide/pods/) you want to debug that uses
+  Init Containers. The example command lines below refer to the Pod as
+  `<pod-name>` and the Init Containers as `<init-container-1>` and
+  `<init-container-2>`.
+
+{% endcapture %}
+
+{% capture steps %}
+
+### Checking the status of Init Containers
+
+The Pod status will give you an overview of Init Container execution:
+
+```shell
+kubectl get pod <pod-name>
+```
+
+For example, a status of `Init:1/2` indicates that one of two Init Containers
+has completed successfully:
+
+```
+NAME         READY     STATUS     RESTARTS   AGE
+<pod-name>   0/1       Init:1/2   0          7s
+```
+
+See [Understanding Pod status](#understanding-pod-status) for more examples of
+status values and their meanings.
+
+### Getting details about Init Containers
+
+You can see detailed information about Init Container execution by running:
+
+```shell
+kubectl describe pod <pod-name>
+```
+
+For example, a Pod with two Init Containers might show the following:
+
+```
+Init Containers:
+  <init-container-1>:
+    Container ID:    ...
+    ...
+    State:           Terminated
+      Reason:        Completed
+      Exit Code:     0
+      Started:       ...
+      Finished:      ...
+    Ready:           True
+    Restart Count:   0
+    ...
+  <init-container-2>:
+    Container ID:    ...
+    ...
+    State:           Waiting
+      Reason:        CrashLoopBackOff
+    Last State:      Terminated
+      Reason:        Error
+      Exit Code:     1
+      Started:       ...
+      Finished:      ...
+    Ready:           False
+    Restart Count:   3
+    ...
+```
+
+You can also access the Init Container statuses programmatically by reading the
+`pod.beta.kubernetes.io/init-container-status` annotation on the Pod:
+
+{% raw %}
+```shell
+kubectl get pod <pod-name> --template '{{index .metadata.annotations "pod.beta.kubernetes.io/init-container-statuses"}}'
+```
+{% endraw %}
+
+This will return the same information as above, but in raw JSON format.
+
+### Accessing logs from Init Containers
+
+You can access logs for an Init Container by passing its Container name along
+with the Pod name:
+
+```shell
+kubectl logs <pod-name> -c <init-container-2>
+```
+
+If your Init Container runs a shell script, it helps to enable printing of
+commands as they're executed. For example, you can do this in Bash by running
+`set -x` at the beginning of the script.
+
+{% endcapture %}
+
+{% capture discussion %}
+
+### Understanding Pod status
+
+A Pod status beginning with `Init:` summarizes the status of Init Container
+execution. The table below describes some example status values that you might
+see while debugging Init Containers.
+
+Status | Meaning
+------ | -------
+`Init:N/M` | The Pod has `M` Init Containers, and `N` have completed so far.
+`Init:Error` | An Init Container has failed to execute.
+`Init:CrashLoopBackOff` | An Init Container has failed repeatedly.
+
+A Pod with status `Pending` has not yet begun executing Init Containers.
+A Pod with status `PodInitializing` or `Running` has already finished executing
+Init Containers.
+
+{% endcapture %}
+
+{% include templates/task.md %}
+