Debug Init Containers
This page shows how to investigate problems related to the execution of
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>.
- Before you begin
- Checking the status of Init Containers
- Getting details about Init Containers
- Accessing logs from Init Containers
- Understanding Pod status
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:
To check the version, enter kubectl version.
- You should be familiar with the basics of Init Containers.
- You should have Configured an Init Container.
Checking the status of Init Containers
Display the status of your pod:
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 for more examples of status values and their meanings.
Getting details about Init Containers
View more detailed information about Init Container execution:
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
status.initContainerStatuses field on the Pod Spec:
kubectl get pod nginx --template '{{.status.initContainerStatuses}}'
This command will return the same information as above in raw JSON.
Accessing logs from Init Containers
Pass the Init Container name along with the Pod name to access its logs.
kubectl logs <pod-name> -c <init-container-2>
Init Containers that run a shell script print
commands as they’re executed. For example, you can do this in Bash by running
set -x at the beginning of the script.
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. |
Pending |
The Pod has not yet begun executing Init Containers. |
PodInitializing or Running |
The Pod has already finished executing Init Containers. |