TCP probe configuration in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a TCP probe in Kubernetes?

A TCP probe checks if a container is accepting TCP connections on a specified port. It helps Kubernetes know if the container is healthy by trying to open a TCP connection.

beginner

Which Kubernetes probe type uses a TCP socket to check container health?

The TCP Socket probe type uses a TCP connection to check if the container is ready or alive.

intermediate

What fields are required to configure a TCP probe in a Kubernetes pod spec?

You need to specify tcpSocket with a port number. Optionally, you can set initialDelaySeconds, periodSeconds, and timeoutSeconds.

intermediate

How does Kubernetes react if a TCP probe fails?

If the TCP probe fails, Kubernetes considers the container unhealthy. For liveness probes, it may restart the container. For readiness probes, it stops sending traffic to the container.

beginner

Example snippet: How to define a TCP readiness probe on port 8080 in a pod spec?

readinessProbe: tcpSocket: port: 8080 initialDelaySeconds: 5 periodSeconds: 10 timeoutSeconds: 1

What does a TCP probe check in Kubernetes?

A If the container accepts TCP connections on a port

B If the container returns HTTP status 200

C If the container's CPU usage is low

D If the container's disk space is sufficient

A TCP probe tries to open a TCP connection to check container health.

Which field specifies the port number in a TCP probe configuration?

A port

B path

C command

D host

The 'port' field inside 'tcpSocket' defines the port to check.

What happens if a liveness TCP probe fails repeatedly?

A Kubernetes ignores the failure

B Kubernetes deletes the pod permanently

C Kubernetes restarts the container

D Kubernetes scales the pod up

Failing liveness probes cause Kubernetes to restart the container.

Which probe type can use a TCP socket check?

A None of the above

B Liveness and Readiness probes

C Only Readiness probes

D Only Liveness probes

Both liveness and readiness probes can use TCP socket checks.

What is the purpose of 'initialDelaySeconds' in a TCP probe?

A Number of retries before failure

B Timeout for each probe attempt

C Interval between probes

D Wait time before starting probes after container start

'initialDelaySeconds' sets how long to wait before the first probe.

Explain how to configure a TCP readiness probe in a Kubernetes pod and why it is useful.

Think about how Kubernetes decides if a container is ready to receive requests.

Describe what happens when a TCP liveness probe fails and how Kubernetes responds.

Consider how Kubernetes keeps containers healthy automatically.