Kube-probe TCP probe failed: address in use

The port specified for the TCP probe is already in use by another process.

Understanding Kube-probe

Kube-probe is a diagnostic tool used within Kubernetes to monitor the health of applications running in a cluster. It helps in determining the state of a container and whether it is ready to accept traffic or needs to be restarted. Kube-probe supports different types of probes, including HTTP, TCP, and command-based probes, each serving a specific purpose in ensuring application reliability.

Identifying the Symptom

When using Kube-probe, you might encounter the error message: TCP probe failed: address in use. This indicates that the TCP probe could not establish a connection because the specified port is already occupied by another process.

Explaining the Issue

The error TCP probe failed: address in use typically arises when the port designated for the TCP probe is not available. This can happen if another application or service is already using the port, preventing the probe from performing its health check. This issue can lead to incorrect health assessments and potentially disrupt the service availability.

Common Causes

  • Another application is running on the same port.
  • Misconfiguration in the Kubernetes deployment or service definition.

Steps to Resolve the Issue

To resolve the TCP probe failed: address in use error, follow these steps:

Step 1: Identify the Process Using the Port

Use the following command to identify which process is using the port:

lsof -i :<port_number>

Replace <port_number> with the actual port number in question. This will list the process ID (PID) and the application using the port.

Step 2: Stop or Reconfigure the Conflicting Process

Once identified, you can either stop the conflicting process or reconfigure it to use a different port. Use the following command to stop the process:

kill -9 <PID>

Replace <PID> with the process ID obtained from the previous step.

Step 3: Update Kubernetes Configuration

Ensure that your Kubernetes configuration files (e.g., Deployment, Service) specify the correct and available port for the TCP probe. You can edit the configuration using:

kubectl edit deployment <deployment_name>

Replace <deployment_name> with your actual deployment name.

Additional Resources

For more information on configuring probes in Kubernetes, refer to the official Kubernetes documentation on probes. Additionally, you can explore Kubernetes Services for understanding how services manage network access to a set of Pods.

Master

Kube-probe

in Minutes — Grab the Ultimate Cheatsheet

(Perfect for DevOps & SREs)

Most-used commands
Real-world configs/examples
Handy troubleshooting shortcuts
Your email is safe with us. No spam, ever.

Thankyou for your submission

We have sent the whitepaper on your email!
Oops! Something went wrong while submitting the form.

Kube-probe

Cheatsheet

(Perfect for DevOps & SREs)

Most-used commands
Your email is safe with us. No spam, ever.

Thankyou for your submission

We have sent the whitepaper on your email!
Oops! Something went wrong while submitting the form.

MORE ISSUES

Made with ❤️ in Bangalore & San Francisco 🏢

Doctor Droid