K3s is a lightweight Kubernetes distribution designed for resource-constrained environments and edge computing. It is a fully compliant Kubernetes distribution that is easy to install and operate, making it ideal for IoT and CI/CD environments. K3s is packaged as a single binary, reducing the complexity and overhead associated with traditional Kubernetes installations.
One common issue encountered in K3s is the PodFailedToSchedule error. This error occurs when a pod cannot be scheduled onto a node. The symptom is typically observed in the pod's status, where it remains in a Pending state, and the events describe a scheduling failure.
The PodFailedToSchedule error usually arises due to insufficient resources or scheduling constraints. Kubernetes uses a scheduler to place pods on nodes based on resource availability and constraints defined in the pod's specification. If the scheduler cannot find a suitable node, the pod remains unscheduled.
To resolve the PodFailedToSchedule issue, follow these steps:
Ensure that your nodes have sufficient resources. Use the following command to check node resources:
kubectl describe nodes
Look for available CPU and memory resources. If resources are low, consider adding more nodes or resizing existing ones.
Examine the pod's resource requests and limits. Ensure they are reasonable and within the capacity of your nodes. Adjust if necessary:
kubectl describe pod <pod-name>
Nodes may have taints that prevent pods from scheduling. Verify node taints with:
kubectl describe node <node-name>
Ensure your pod has the necessary tolerations to match these taints.
Ensure that any node selectors or affinity rules in your pod specification are not overly restrictive. Adjust them as needed to allow scheduling on available nodes.
For more information on troubleshooting scheduling issues in Kubernetes, refer to the official Kubernetes Scheduling Documentation. Additionally, the K3s Documentation provides insights specific to K3s environments.
(Perfect for DevOps & SREs)
(Perfect for DevOps & SREs)
