Kubernetes, often abbreviated as K8s, is a popular open-source container orchestration platform designed for automating the deployment, scaling, and management of containerized applications. It was originally developed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF). However, sometimes pods can get “Pods stuck in terminating status” error, which prevents new pods from being scheduled on the same node. This can be frustrating, but fortunately there are several ways to fix this issue.
In this tutorial we will discuss about reasons of this error, negative impacts of th error and some important steps of resolving the “Kubernetes Pods Stuck Terminating Status” error,
Table of Contents
Why Does This Error Occur?
Identifying the root cause of this problem is critical while fixing this issue. This can be due to several reasons such as finalizers, hanging processes, or network issues. Some reasons why pods may get stuck at a “terminating state” includes:
1. Lack of Resources
Kubernetes pods need a proper amount of resources to work without any problem. If there is not sufficient number of resources, multiple pods may compete with each other for resources, which may cause one of the pods to be stuck in a terminating state.
2. Issue with Pod Configuration
An issue with the configuration of the pod may result in it being stuck in a terminating state. If there are finalizers in the pod, the root problem may be that the finalizers are not completed.
3. An Underlying Node May Be Broken
When Kubernetes pods get stuck in the Terminating state, it’s often due to underlying node malfunctions. Diagnosing this issue can be challenging because pods frequently terminate, making it difficult to identify which ones are lingering too long.
4. Finalizers Blocking Removal
Finalizers are for the purpose of ensuring that specific cleanup tasks are executed before a resource is deleted. If a finalizer fails to complete its assigned task, it can prevent the process of deletion. To address this issue, you may need to manually check and remove or delete finalizers.
5. Hanging Processes
If the processes within a container fail to exit properly, it may prevent the pods from terminating. To fix this issue, review the logs and events associated with the pod to identify any hanging processes.
6. Problems with Persistent Volumes
When a pod relies on persistent volumes or any problems with the underlying storage Pods can terminate the process. To address this issue, it’s crucial to examine the status of the persistent volumes and identify any issues with the storage backends.
7. Kubelet Issues
The Kubelet issues on the node may prevent it from properly handling the termination request. To fix this issue check the status of the node and restart the Kubelet if necessary.
8. API Server Problems
It’s essential to consider potential issues related to the Kubernetes API server when dealing with Pods stuck in terminating status. The API server plays a critical role in managing the cluster, and any problems there can impact pod termination
Fixing Kubernetes Pods Stuck In Terminating Status Error
Here are some important steps to fix this error, by following these steps you can resolve the issue-
Step-1: Identify the Pod
First process in fixing the error of Kubernetes pods stuck in terminating status is to identify the pod causing the problem. You can do this by running the following command.This command will show you a list of all pods that are in the terminating state.
kubectl get pods –all-namespaces | grep Terminating
Step-2: Checking the Pod Status
After the first process of identifying the pods causing the problem, check this Pod’s status to see why it’s stuck in the terminating state. You can do this by running the following command. This command will give you a description in detail of the pod, including its current status and any events that have occurred.
kubectl describe pod <pod-name> -n <namespace>
Step-3: Remove the Finalizer
If a pod gets stuck in the terminating condition, it may be likely because it has a finalizer that prevents it from being deleted. To remove the finalizer, you need to run the following command.This command will remove all finalizers from the pod, allowing it to be deleted.
kubectl patch pod <pod-name> -n <namespace> -p ‘{“metadata”:{“finalizers”:[]}}’ –type=merge
Step-4: Force Delete the Pod
If the previous step of removal of the finalizer did not work, you need to delete the pod forcefully by running the following command.This command will forcefully delete the pod, ignoring the grace period.
kubectl delete pod <pod-name> -n <namespace> –grace-period=0 –force
Step-5: Check Node Status
If the pod still stucks in the terminating state after forcefully deletion , you should check the status of the node it was running on. You can do this by running the following command.This command will give you a detailed description of the node, including its status and any events that have occurred.
kubectl describe node <node-name>
Step-6: Restart the Kubelet
If the above mentioned solutions do not resolve the issue, then you should try to restart the Kubelet. If you do have access, you should restart the kubelet process by SSHing into the node. You can do this by running the following command.This command will restart the kubelet service, which is responsible for managing pods on the node.
systemctl restart kubelet.service
What are the Negative Effects of This Error?
When Kubernetes pods get stuck in the Terminating state, it can affect cluster’s performance, resource management, and application reliability. Here are the key impacts of this error:
1. Resource Waste
Stuck Kubernetes Pods in the terminating state consumes CPU and memory resources, which can lead to resource waste. Stuck Kubernetes pods can hold onto persistent volumes, preventing other pods from using those storage resources.
2. Deployment Issues
Automatic scaling might be affected as Kubernetes maintains the desired number of replicas but it can not free up resources occupied by terminating pods. Deployment processes, including rollouts and rollbacks, might be delayed because the new pods cannot start until the old pods are completely terminated.
3. Application Availability
If terminating pods are part of a service, they start to receive traffic, causing potential service disruptions or degraded performance. Network connections may not be drained properly, leading to interrupted user sessions or failed transactions.
4. Operational Complexity
Stuck Kubernetes pods in terminating status can create noise in monitoring and logging systems and makes it difficult to identify other issues. Operators need to manually intervene to delete stuck pods, increasing operational overhead and complexity.
5. Scheduling Delays
Nodes running stuck kubernetes pods may report high usage of resources, causing the scheduler to avoid placing new pods on those nodes, causing the delays in scheduling new workloads.
6. Networking Issues
Stuck pods strat to occupy IP addresses, which can lead to IP address exhausting in clusters with a limited IP range. Services may continue to list terminating pods as active endpoints, leading to requests to be sent to pods that are no longer functional.
7. Node Health and Stability
Stuck pods Nodes may increase load on the kubernetes, affecting the node’s overall health and stability. The capacity of nodes to serve new pods is reduced, which affects the ability of the cluster to handle new workloads.
Overall, Kubernetes pods stuck in the Terminating status affects resource utilization, efficiency, application availability, operational simplicity, scheduling efficiency, networking, and node stability. It’s important to address the underlying causes to maintain the health and performance of the Kubernetes cluster.
Best Practices to Prevent Pods Being Stuck in the Future
There are some important steps and best practices you can take to make sure this problem doesn’t occur in the future-
- Thoroughly check your pods to see if they are functioning properly before deploying them.
- Ensure that you have sufficient resources. A lack of resources may cause the pods to start competing with each other for resources, which may cause the pods to be stuck in a terminating state.
- Make sure your pods don’t use too many resources.
- Make sure to keep your Kubernetes cluster up to date to avoid any problems in the future.
- Constantly check to see if there are any issues with the configuration or the code of your pods.
- Get Kubernetes Professional Consulting Service With SupportFly and Hire the highly skilled and experienced team for the Kubernetes Consulting, Support and Management.
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Conclusion
The problems caused by Kubernetes pods being stuck in the Terminating state make it essential to take extra precautions before deployment. Ensure that there are no problems with the pod itself which can lead to it getting stuck. Additionally, be vigilant about avoiding potential triggers, such as resource shortages or an outdated Kubernetes cluster. If this issue arises despite these precautions, the first step is to identify the root cause and apply an appropriate solution.
