Kubernetes is a powerful tool for managing complex containerized applications. It allows the swift deployment, scaling, and management of applications by developers.
But great power also comes with great responsibility, and Kubernetes has its own problems that can give developers trouble. The "pod stuck terminating" problem in Kubernetes is one of the most hated ones.
We'll go over what this problem is, common causes, diagnosing a stuck pod, approaches to fixing it, a step-by-step guide to fixing it, best practices for preventing the problem in the future, Kubernetes pod troubleshooting advice, helpful tools for monitoring and managing Kubernetes pods, courses and tutorials on Kubernetes pod management, and more in this blog.
What is the Kubernetes "Pod Stuck Terminating" Issue?
When a pod stays in the "Terminating" state for an extended amount of time, it can cause the Kubernetes pod to have a terminating issue. This can be quite annoying for developers and can be caused by a variety of different problems.
There are many ways in which the problem may show up. For example, you can see that your pod is continuously consuming resources while it is trapped in the "Terminating" state. Although the Docker container and underlying PID have been terminated, you can check the host to which the pod was assigned. However, Kubernetes is indicating that it is still in the terminating stage.
Whatever the source, developers may have a great deal of trouble and major delays while deploying apps if a Kubernetes pod becomes stuck in terminating.
What Does "Terminating" Mean?
A pod in Kubernetes is in the process of shutting down when it has the "Terminating" status. Upon deletion, a pod experiences a termination phase during which Kubernetes makes sure the pod is terminated properly. This procedure includes:
Sending a SIGTERM Signal: Kubernetes notifies the containers in a pod to terminate.
Grace time: Within a predetermined grace time, Kubernetes waits for the containers to end within a grace period.
Forcing Shutdown: Kubernetes sends a SIGKILL signal to the containers to forcefully terminate them if they don't shut down within the grace period.
If any of these processes meet problems, the pod may become stuck in the "Terminating" state.
Common Causes of Pods Becoming Stuck
There are several possible causes for the Kubernetes pod stuck in terminating issue. The most typical reasons consist of:
Insufficient resources: To function correctly, Kubernetes pods need enough resources. Insufficient resources could cause the pod to become stuck in the "Terminating" state. Checking your worker node's condition at the moment the pod stopped responding is crucial. If every system resource was used, such as a disk filling up, Kubernetes might not be the primary problem to identify.
Competition for resources: If more than one pod competes for the same resources, one of the pods may become stuck in the "Terminating" state as it waits for available resources.
Pod issues: The pod may become stuck in the "Terminating" stage if there is a problem with the pod itself. This can be the result of a configuration error, a code error, or another issue.
Problems with the Kubernetes cluster: The pod may become stuck in the "Terminating" state if there is a problem with the Kubernetes cluster itself. When cluster communications break down from a blip or network split, this may happen. Even if the worker node is operating as it should, it is unable to inform the Kubernetes API of its appropriate operation.
How to Diagnose a Stuck Pod
There are a few actions you may take to find the problem if you find that your Kubernetes pod is stuck in the "Terminating" state.
Examining the logs should be your first step. Look through the pod's logs for any error messages or warnings that might point to the problem's root cause.
The pod's resource use should then be examined. The pod may be causing problems if it is using excessive amounts of resources.
Subsequently, you need to examine the server's resource use at the moment the pod entered a terminating condition. In case the server's disk ran out and the pod became stuck, but the system resources appear to be functioning normally presently, it's possible that the server's processes are in an unidentified or unsalvageable condition that requires a reboot.
Lastly, you have to use kubectl to verify the node's state. The node should be drained—which might not be possible—rebooted, and have its health assessed again if it is not reporting itself as healthy via kubectl get nodes.
A Step-By-Step Guide to Solving the Issue
In the event that your Kubernetes pod becomes stuck in the "Terminating" state, follow these steps to resolve the problem:
- Check the worker node using
ctrfor signs of stuck containers or stuck PIDs.
The process executing inside the container is not correctly listening to system signals like SIGHUP if the node has stuck PIDs or a stuck container. Send the program developers a bug report if you need help or a patch.
Check the worker kubelet process logs for signs errors
Check the master's kubelet process logs for signs of errors
Check the master's kube-scheduler process logs for signs of errors
Check the master's kube-controller-manager process logs for signs of errors
Check the master's kube-apiserver process logs for signs of errors
Your cluster's nodes should begin rolling reboots if any of these tests reveal a problem. Return to the masters after assisting the affected worker first. It's unlikely that other cluster members require a reboot.
- Check the server's resources at the moment the pod entered a terminating condition.
Why choose SupportFly’s Professional Kubernetes Consulting Services
Supportfly plays a key role in managing Kubernetes deployments, which may be a difficult and time-consuming operation. We handle every facet of Kubernetes implementation and optimization, from planning and evaluation to cluster design, application containerization, security implementation, monitoring, and CI/CD integration.
SupportFly provides complete consulting services for Kubernetes. Our group of experts in Kubernetes will help you with:
Kubernetes Assessment And Planning
Kubernetes Cluster Design And Deployment
Application Containerization And Orchestration
Kubernetes Security And Governance
Kubernetes Monitoring And Performance Optimization
Continuous Integration And Delivery (CI/CD) With Kubernetes
Conclusion
Although handling a Kubernetes pod that has entered the "Terminating" state can be difficult, knowing the typical causes and how to fix them will help you resume your work as soon as possible. You may successfully manage and mitigate termination issues in your Kubernetes system by putting best practices into practice and following the troubleshooting procedures mentioned above.