How do I kill the process using port 10250?

On macOS & Linux, run: "sudo systemctl stop kubelet || kill -9 $(lsof -t -i:10250)". On Windows PowerShell (as Admin), run: "Stop-Service kubelet -Force -ErrorAction SilentlyContinue".

Why am I getting "port 10250 already in use" (EADDRINUSE)?

This occurs when another background instance of kubelet or a zombie process is already bound to port 10250. Use the kill commands above to free the port immediately.

DevOps & Cloud

Risk: Critical

Port 10250 — Kubernetes Kubelet API

Q: Is Port 10250 safe to expose to the public internet?

Risk level is Critical. If --anonymous-auth=true is enabled, attackers can query Kubelet port 10250 to execute arbitrary commands inside running containers (exec/run). Require webhook/certificate authentication.

Port 10250 is the HTTPS listening port for the Kubernetes Kubelet daemon on worker nodes, allowing control plane components to query node stats and execute pod commands.

PORT NUMBER

10250

PROTOCOL

TCP

DEFAULT PROCESS

kubelet

FIREWALL TARGET

10250/tcp

Instant Terminal Fixes for Port 10250

macOS & Linux Terminal

1. Check who is listening on port 10250:

curl -k -I https://localhost:10250/pods

2. Kill process occupying port 10250 (EADDRINUSE fix):

sudo systemctl stop kubelet || kill -9 $(lsof -t -i:10250)

3. UFW Firewall Allow rule:

sudo ufw allow from 10.0.0.0/8 to any port 10250 proto tcp

Windows PowerShell (Admin)

1. Check listening port:

Get-NetTCPConnection -LocalPort 10250

2. Force kill process on port 10250:

Stop-Service kubelet -Force -ErrorAction SilentlyContinue

3. Docker Port Forwarding Mapping:

# Kubelet runs directly on node host rather than standard container

Common Error Encountered

Unauthorized error 401 when communicating with Kubelet on port 10250.

Security Advisory & Hardening

If --anonymous-auth=true is enabled, attackers can query Kubelet port 10250 to execute arbitrary commands inside running containers (exec/run). Require webhook/certificate authentication.

Frequently Asked Questions

Port 10250 Questions & Answers

Common questions regarding default services, kill commands, and firewall configurations.

Port 10250 is commonly used for Kubernetes Kubelet API. Port 10250 is the HTTPS listening port for the Kubernetes Kubelet daemon on worker nodes, allowing control plane components to query node stats and execute pod commands.

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