How to Fix Exit Code 137 on Kubernetes?

Exit Code 137 on Kubernetes can be a perplexing issue for many users, causing disruptions and hindering the smooth operation of containerized applications. This article aims to demystify this error code, providing you with a comprehensive guide on understanding, diagnosing, and resolving Exit Code 137 issues in your Kubernetes environment.

1. Understanding Exit Code 137:
   To begin, it's crucial to grasp the significance of Exit Code 137. This code indicates that a container process was terminated due to exceeding its memory limit. In the world of Kubernetes, managing resource limits effectively is essential for maintaining the stability and performance of your applications.

2. Diagnosing the Problem:
   Before diving into the solution, it's important to diagnose the root cause of Exit Code 137. Use the following commands to gather relevant information:

   kubectl get pods
   kubectl describe pod <pod_name>
   kubectl logs <pod_name>
   

   Analyze the output to identify any patterns or specific containers experiencing memory issues.

3. Adjusting Resource Limits:
   One common cause of Exit Code 137 is insufficient memory allocation for your containers. To address this, adjust the resource limits in your pod specification. Open the YAML file for your deployment and modify the resources section:

   resources:
     limits:
       memory: 512Mi  # Adjust as needed
   

   Apply the changes using:

   kubectl apply -f <your_deployment_file.yaml>
   

4. Monitoring and Scaling:
   Implement proactive monitoring to detect potential memory issues before they result in Exit Code 137. Tools like Prometheus and Grafana can help you set up robust monitoring solutions. Additionally, consider horizontal pod autoscaling to dynamically adjust resources based on demand.

   kubectl autoscale deployment <deployment_name> --cpu-percent=70 --min=1 --max=10
   

   This command sets up autoscaling for the specified deployment, adjusting the number of pods based on CPU usage.

5. Cleaning Up Zombie Processes:
   Sometimes, zombie processes can contribute to memory-related problems. Identify and terminate lingering processes within your containers using the following:

   kubectl exec -it <pod_name> -- /bin/bash
   ps aux | grep <process_name>
   kill -9 <process_id>
   

   Repeat this process for any suspicious or resource-consuming processes.

6. Optimizing Application Code:
   Evaluate your application code for memory leaks and inefficiencies. Utilize profiling tools and conduct thorough code reviews to ensure optimal resource utilization.

So, addressing Exit Code 137 on Kubernetes requires a combination of adjusting resource limits, proactive monitoring, scaling strategies, and code optimization. By following the steps outlined in this guide, you can effectively diagnose and resolve memory-related issues, ensuring the seamless operation of your containerized applications.