How To Resolve OOMKilled Kubernetes Errors (Exit Code 137)

Background

In Kubernetes, the OOMKilled error (also indicated by exit code 137) means that a container within a pod was terminated because its memory usage exceeded the defined limit. A pod can specify a memory limit – the maximum amount of memory a container is allowed to use; if a container uses more memory than its memory limit, it is terminated with an OOMKilled status. A pod can be terminated with an OOMKilled status if the pods on a node exceed the defined limit.

Important: To ensure system integrity, identify the root cause of the OOMKilled error and address it appropriately; simply increasing the memory limit might only mask the problem, and could result in a more catastrophic failure at a later time.

Solution

There are many reasons why a container or a pod might be terminated with an OOMKilled error, but a systematic approach that includes the following should help to identify the specific issue:

• Check the pod logs: Check the logs of the pod to determine which container is using too much memory.

• Analyze the memory usage: Analyze the memory usage of the containers within the pod to determine what is causing the high memory consumption.

• Evaluate memory limits: If the memory usage of a container is consistently high, you can raise memory limits for the container. This will prevent the container from using more memory than the specified limit. You can do this using the limits.memory field in the pod specification.

• Optimize the application: Evaluate if the memory usage is high due to a memory leak or an inefficient algorithm in the application; consider optimizing the application code to reduce its memory usage by reducing the memory footprint of applications, caching data in memory, or limiting the number of processes running in the containers

• Scale the number of replicas: If the pod is part of a ReplicaSet or a Deployment, consider scaling the number of replicas up or down to balance the memory usage across multiple instances.

• Increase node resources: If the memory limit is set correctly and the issue persists, you might need to increase the memory resources of the node hosting the pod. You can do this by scaling the node or by adding more nodes to the cluster.

• Monitor memory usage: Set up monitoring and logging to track pod and container memory usage over time, and adjust memory limits and optimizations as necessary.

These steps should help you resolve an OOMKilled error in your Kubernetes environment and prevent it from happening in the future; however, it is important to remember that every situation is unique and may require a different approach to resolve the error.