Fixing CreateContainerError in Kubernetes Pods

How most encounter CreateContainerConfigError or CreateContainerError in Kubernetes?

When attempting to create a container within a pod, Kubernetes may encounter two types of errors: CreateContainerConfigError and CreateContainerError. These errors arise before the container reaches the running state.

To encounter these errors, you can execute the command "kubectl get pods" and view the pod status, which will display the error message shown below.

NAME READY STATUS RESTARTS AGE
pod-test-a 0/1 CreateContainerConfigError 0 0m53s
pod-test-b 0/1 CreateContainerError 0 2m05s

This article will give you some tips on how to identify and fix these errors when they are easy to solve. However, if they are more complicated, you will need to use advanced methods and tools that we won’t cover here. Keep reading until the end to learn about a tool that helps find and solve these errors quicker.

Common CreateContainerError Causes and Solutions

When you deploy Kubernetes, you may encounter the CreateContainerError, which indicates that the container runtime failed to create a container for your pod. This error can have different causes and resolutions depending on the situation. Next, we will discuss two common scenarios that can lead to this error and how to fix them.

Most Common Cause of Error: ConfigMap or Secret is Missing

ConfigMap

In Kubernetes, a ConfigMap, is an API object that stores configuration data in a key-value format, separated from container images. It enables one or more containers within a Pod to access the configuration data, making it easier to manage an application's settings across different environments without rebuilding the container image.

Secrets

‍In Kubernetes, Secrets are API objects used to store sensitive data, such as passwords and access keys, in an encrypted format. They enable secure access to this data by authorized containers and users within the cluster. Secrets, like ConfigMaps, separate sensitive data from container images, enabling secure and efficient deployment of applications.

Simplified Solution

‍To resolve the issue, locate the absent ConfigMap or Secert and either generate it within the namespace or attach another file that already exists.

Steps to Resolving Issue

1. Run the command "kubectl describe" and look for any signs of pods missing Secrets or ConfigMaps. If the Kubernetes Pod is missing one of these, it would show in the response message as: kubelet  Error: configmap "configmap-2" not found
2. Once you have the name of the ConfigMap or Secert you believe to be missing, verify this with the "kubectl get (configmap_name)" command. If this returns null, then the file you are searching for is missing.
3. Add a the missing file if it already exists or create the ConfigMap or Secret and place them in the pod.
4. Redo Step 2 with the "get configmap" or "get secrets" until you confirm the files are in the correct location.
5. Now verify the Pods Status to ensure that it is up and running with the "kubectl get pods" command.
   

NAME READY STATUS RESTARTS AGE
pod-test-a 0/1 Running 0 0m59s

It's worth noting that there is a method of controlling Kubernetes Secrets and ConfigMaps directly from within MySQL. This approach allows users to see everything in chart form, making it easy to find and replace file names. However, users may run into limitations when it comes to complex configurations or larger environments, making it necessary to revert to another tool to fully correct issues within SQL.

Other Causes of CreateContainerError and CreateContainerConfigError

To diagnose and resolve a CreateContainerError, follow these steps:

STEP 1: Collect Pod Info

Retrieve the description of the pod by running the following command and save to a text file:

kubectl describe pod [pod_name] /tmp/troubleshooting_describe_pod.txt

STEP 2: Look into Pod Events Output

Search through the text file that you just created for any of the below messages in your Pod Events:

Is waiting to start

Starting container process caused

Container name [cont_name] is already in use by container

No command specified

STEP 3: Troubleshoot the Error

When error is "is waiting to start", it means that an object mounted by the container could not be found or is missing.

• *Be certain it is not related to ConfigMaps or Secrets, as mentioned earlier.*
• Examine the pod's configuration and verify that all items assigned to it or the container are accessible in the same workspace. If not, either generate them or modify the manifest to point to an existing object.

When error is "starting container process caused",

• Observe words following the "container process caused" message to see the error that occurred when the container was started.
• Find the error. Then modify the image or the container start command to fix.

When the error is "container name [cont_name] is already in use by container", it means that the container runtime did not delete a previous container created with a similar name.

• To fix this error, sign in with root access on the node and open the kubelet log located at /var/log/kubelet.log.
• Find the issue in the kubelet log and solve it by reinstalling the container runtime or the kubelet. Sometimes this requires users to re-register the node with the cluster.

When error is "no command specified", it means that the image configuration and pod configuration did not specify which command to run to start the container.

• To fix this error, edit the image and pod configuration and add a valid command to start the container.

Please note that these steps will only resolve the most common causes of CreateContainerError. If one of these quick fixes does not work, a more complex diagnosis procedure may be necessary to identify the contributing factors in the Kubernetes environment and resolve the problem.

Introducing Botkube for Effortless Kubernetes Error Troubleshooting

Kubernetes troubleshooting can be a daunting task without the right tools. Even with best practices in place, errors can still occur, leading to stressful and time-consuming investigations. That's why we developed Botkube – a tool that simplifies the process of Kubernetes troubleshooting for DevOps teams.

Botkube provides the following features to streamline the troubleshooting process:

Change Intelligence: Every error in Kubernetes is a result of a change. With Botkube, you can quickly identify who made what changes and when they made them.

Effortless Notifications: Botkube integrates seamlessly with existing communication channels like Slack, providing real-time notifications so you can quickly resolve issues as they occur.

Comprehensive Visibility: Botkube offers a complete timeline of all code and configuration changes, deployments, alerts, code diffs, pod logs, and more. All this information is presented in a single pane of glass, with simple drill-down options for further investigation.

Insight into Service Dependencies: Botkube makes it easy to visualize cross-service changes and the ripple effects of such changes across your entire system.

If you're interested in exploring Botkube and its features, sign up for a free trial using this link. With Botkube, you'll never have to waste precious time and resources looking for needles in haystacks again.