The Exit Code 1 error indicates that a container has shut down, suggesting an issue with your containerized application. This can be frustrating for software developers.
In this article, we will delve into the cause of this error, causes, and a guide to resolve it.
What is The Exit Code 1
When an application exits with code 1 on Unix/Linux, it means something went wrong and the system kills the process with SIGHUP (Signal 7).
Container exit codes are useful for troubleshooting pods in Kubernetes. You can use kubectl describe pod [POD_NAME] to check the pod status and logs.
Exit code 1 in containers indicates an application error or an invalid image reference. You need to examine the container and its applications to find the root cause.
Causes Of Exit Code 1
Here are some of the case scenarios that can lead to Exit Code 1:
- Application Runtime Errors: These are errors that occur when the application running in the container encounters an exception or fails to complete a critical task. For example, a missing dependency, or a configuration issue.
- Container Configuration Issues: If the command or arguments in your container spec are wrong, the container will stop right away. For instance, if the command you gave in your container spec is not valid or has a typo, the container will end with code 1.
- Failed health checks: These are errors that occur when the container fails to pass the liveness or readiness probes that Kubernetes uses to monitor the pod health. For example, a timeout, a connection error, or a wrong response.
Diagnosing Exit Code 1
Check Container Logs
To fix containers that end with code 1, look at their logs. Logs usually show the output of the container process and the reason for its termination. Run the command kubectl logs <your-pod-name> to see the container logs:
kubectl logs <your-pod-name> -c <pods'container-name>
Here is an example output of the above command:
Error: Invalid configuration
at /app/server.js:20:21
at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
...
Process exited with status code 1
Verifying Container and Application Configurations
Review your Kubernetes files and application config files. Use this command to view your Kubernetes deployment information:
kubectl get deployment <your-deployment-name> -o yaml
Ensure to check for any misconfigurations in environment variables, or the volume mounts.
Check Container Resources
Check the container resources (CPU, memory, disk, etc.) and make sure they are sufficient and properly allocated. You can use the following command:
kubectl top pod [POD_NAME]
Inspect to see the resource usage of the pod and adjust the resource limits and requests accordingly.
Best Practices to Deal With Exit Code 1 Error
- Check Container Entrypoint: Make sure the container’s entrypoint script can run and has the right shebang line (#!/bin/bash). A frequent mistake is ‘No such file or directory’ if the entrypoint is missing or not runnable.
- Utilize Liveness Probes: Configure liveness probes in Kubernetes. Pods frequently restarting, as shown by
kubectl get events, suggest failing liveness checks. - Use Init Containers: Use init containers to set up the environment properly before the main application begins. If init containers fail,
kubectl describe pod <pod-name>will show logs with environment problems. - Use Init Containers: Make sure the environment is ready before the main application starts with init containers. You can see the logs with environment issues if init containers don’t work by using
kubectl describe pod <pod-name>. - Don’t Use Fixed Paths: Use paths that depend on the current location or environment variables instead. The container’s file system may not have the paths that are fixed in the code, which can cause ‘File not found’ errors.
Conclusion
In this article, we have learned what the exit code 1 error in Kubernetes means, what are the common causes and how to troubleshoot them. We have also seen some best practices to prevent this error from occurring in the future, such as using proper health checks, logging, monitoring and resource management. By following these steps, you can ensure your Kubernetes pods run smoothly and reliably, without crashing or restarting unexpectedly.
