How to Troubleshoot Pod Errors ?

The first step in troubleshooting a pod is getting the status of the pod. Run the below command to know the status of the pods.

kubectl get pods

Now that you know the error type, describe the individual pod and look through the events to see what is generating the pod error.

To get detailed information about the pod. Run the below command.

kubectl describe pod <pod-name>

Now let’s look at some of the most common pod errors and how to troubleshoot them.

Troubleshoot ErrImagePullBackOff

Run the below command to get the pod details.

kubectl get pods

If you see ErrImagePullBackOff in pod status, it is most likely for the following reasons.

• The supplied image does not exist in the registry.
• A misspelling in the image’s name or tag.
• Image pull access was denied from the given registry due to credential issues.

If you check the pod events, you will see the ErrImagePull error followed by ErrImagePullBackOff. This means the kubelet stops trying to pull the image again and again.

kubectl describe pod <pod-name>

• Error reference

1. Troubleshoot Error: InvalidImageName

Run below command to know status of the pods.

kubectl get pods

• If you specify a wrong image URL in the manifest, you will get the InvalidImageName error.

For example, if you have a private container registry and you mention the image name with https, it will throw the ‘InvalidImageName’ error. You need to specify the image name without https.

• If you have trailing slashes in the image name, you will get both ‘InspectFailed’ & ‘InvalidImageName’ errors. You can check it by describing the pod.

• Error reference

2. Pod Configmap & Secret Errors[CreateContainerConfigError]

CreateContainerConfigError is one of the common errors related to Configmaps and Secrets in pods.

This normally occurs due to two reasons.

• You have the wrong configmap or secret keys referenced as environment variables
• The referenced configmap is not available

If you describe the pod you will see the following error.

If you have a typo in the key name, you will see the following error in the pod events.

To rectify this issue,

• Ensure the config map is created.
• Ensure you have the correct configmap name & key name added to the env declaration.

Let’s look at the correct example. Here is a configmap where service-name is the key that is needed as an env variable inside the pod.

Here is the correct pod definition using the key (service-name) & configmap name (nginx-config)

Kubernetes (K8s) installations frequently present issues from multiple perspectives, including pods, services, ingress, non-responsive clusters, control planes, and high-availability configurations. Kubernetes pods are the smallest deployable units in the Kubernetes ecosystem, each containing one or more containers that share resources and a network. Pods are intended to execute a single instance of an app or process and are built and destroyed as required. Pods are essential for scaling, updating, and sustaining applications in a Kubernetes environment.

In this article, we will explore Pod troubleshooting strategies in Kubernetes, offering expert insights to help you ensure the seamless performance of your applications.