K8s Node Not Ready

A Kubernetes node's status is 'NotReady', indicating it cannot schedule or run pods. The kubelet on the node is failing to report a healthy status to the control plane.

Common Causes

Kubelet service is stopped or crashed on the node.
Insufficient memory or disk pressure on the node.
Network connectivity issues between the node and the API server.
Docker/Container Runtime is not running or is unhealthy.
Node has exhausted CPU, memory, or PID resources.

How to Fix

1 Check Node and Kubelet Status

First, get the detailed status of the node and check if the kubelet service is active.

BASH

 $ kubectl describe node <node-name>
# On the affected node, check the kubelet service:
systemctl status kubelet

2 Restart Kubelet Service

Often, restarting the kubelet service can resolve transient issues.

BASH

 $ # On the affected node:
sudo systemctl restart kubelet
# Check status again:
sudo systemctl status kubelet

3 Check Node Resources and Disk Pressure

Inspect if the node is under MemoryPressure or DiskPressure, which can cause a NotReady status.

BASH

 $ kubectl describe node <node-name> | grep -A 5 -i pressure
# Check disk space on the node:
df -h
# Check memory usage:
free -h

4 Inspect Kubelet Logs

Examine the kubelet logs for specific error messages indicating the root cause.

BASH

 $ # On the affected node:
sudo journalctl -u kubelet --no-pager | tail -100

5 Drain and Cordon the Node (If Needed)

If the node is problematic, safely evict pods and mark it unschedulable for maintenance.

BASH

 $ kubectl cordon <node-name>
kubectl drain <node-name> --ignore-daemonsets --delete-emptydir-data