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In this guide, we explore common Kubernetes container creation errors—specifically, CreateContainerConfigError and CreateContainerError. We will walk through the Kubernetes container lifecycle, highlighting the stages—from image pulling to container startup—and identify where these errors occur. Below is an initial pod status output displaying both errors:
An extended output with additional flags looks as follows:

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Container Creation Lifecycle in Kubernetes

Understanding the container lifecycle is crucial for troubleshooting these issues. The container creation process is divided into four main stages:
  1. Image Pulling
    Kubernetes pulls the container image (e.g., nginx:latest) from the image registry to the node. With correct registry credentials, this step completes successfully.
  2. Container Configuration
    Kubernetes creates the container configuration by setting environment variables, command arguments, resource limits, volume mounts, network settings, security contexts, and more.
A CreateContainerConfigError is raised if required configurations (such as a referenced Secret or ConfigMap) are missing.
  1. Container Creation
    The container runtime (e.g., containerd or Docker) creates the container using the pulled image. This involves establishing the filesystem and Linux namespaces.
A CreateContainerError is typically due to issues encountered by the container runtime while setting up the container.
  1. Container Start
    Finally, the container’s process starts by executing the defined command or entry point. Errors occurring at this stage are often referred to as run container errors, signaling problems with the process startup.
The CreateContainerConfigError usually points to misconfigurations such as referencing a Secret or a ConfigMap that doesn’t exist, while the CreateContainerError suggests that the container runtime could not complete the container creation.

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Troubleshooting CreateContainerConfigError

Let’s begin with demo A, which encounters a CreateContainerConfigError. The pod description for demo A shows the error in the container state:
Reviewing the Events section reveals the root cause:
The pod is referencing a Secret named demo-a-secret that does not exist in the cluster. The environment variable KEY_A is configured to use the value from this Secret (key: some_key). Without this Secret, Kubernetes cannot inject the necessary environment variable, leading to the CreateContainerConfigError. Below is the relevant portion of the pod’s YAML configuration:
To resolve this error, create the missing Secret by applying a YAML file similar to the following:
After creating the Secret, the environment variable can be properly injected and the pod transitions from the error state. An updated pod status might look like this:

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Troubleshooting CreateContainerError

Next, let’s investigate demo B which shows the CreateContainerError. The pod description for demo B indicates that no command or entry point is specified:
The detailed pod description for the failing container points out the issue:
The image ngheith/no-entry-point:v5 does not define an entry point, and the pod configuration does not override this by providing a command. To resolve this issue, update the deployment to include a valid command that keeps the container running—for example:
After updating the deployment, verifying the pod status should show that the container is now running without the creation error:

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Demonstrating a Run Container Error

In some cases, the container is created successfully but fails to start its process due to an invalid command. For example, a deployment might define an incorrect command (gibberish), causing the container to crash after creation:
The resulting pod status shows a CrashLoopBackOff:
Describing the troubled pod for demo C indicates that the defined command (jibberish) is not recognized:
To resolve this RunContainerError, update the deployment with a valid command. For example, to keep the container active, modify the deployment snippet as follows:
After applying this change, checking the pod statuses should reveal that the container runs without errors:

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Final Status Summary

Below is a summary of the final pod status after troubleshooting all container creation steps:
By understanding the container lifecycle and the specific error messages, you can more effectively narrow down troubleshooting efforts in Kubernetes environments. For more detailed troubleshooting techniques, check out the Kubernetes Documentation and resources on Container Runtime Troubleshooting.
The image shows a terminal interface for managing Kubernetes pods using K9s, displaying two pods with errors: "CreateContainerConfigError" and "CreateContainerError."

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