CrashLoopBackOff is a common Kubernetes error which indicates a pod that is constantly crashing in an endless loop.
Common Causes:
- Insufficient resources
- Issues with init-container setup
- Misconfigurations
- Deploying failed services / apps
- Locked file / database
- Unable to load the config file
- Connection issues
- Failed references
Troubleshooting:
1. Check for “Back Off Restarting Failed Container”
$ kubectl describe pod [name].
2. Search the Logs From Previous Container Instance
$ kubectl logs –previous –tail 10
3. Check kubectl Deployment Logs
$ kubectl logs -f deploy/ -n
4. Access the CrashLoop container to identify the issue
Step 1: Locate the entrypoint and cmd for the container image
$ docker pull [image-id] to pull the image.
$ docker inspect [image-id]
Step 2: Change entrypoint
Since the container has crashed and couldn’t start, we need to temporarily change the entrypoint to tail -f /dev/null.
Step 3: Install debugging tools (e.g. curl or vim) if its not there already
$ sudo apt-get install [name of debugging tool]
Step 4: Check for missing packages or dependencies
Step 5: Check application configuration
e.g. Inspecting environment variables and the credentials of the database configuration file.