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

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

• iximiuz Labs
• Killercoda
• KodeKloud
• Play with Kubernetes

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 <pod-name> --template '{{.status.initContainerStatuses}}' 

This command will return the same information as above, formatted using a Go template.

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.