A container probe is a Kubernetes health test that evaluates a container using a network request, command, or other configured check.
A container probe is a Kubernetes health test that checks whether an application is working. Kubernetes defines probes in the Pod model; Docker HEALTHCHECK instructions are ignored. section 15.3
Choose the probe action according to the failure you need to handle:
HTTP GET checks an endpoint and response code. section 15.3
TCP checks whether the application has an open listening port. section 15.3
A command runs a custom check inside the container. section 15.3
A readiness probe removes an unhealthy Pod from Service endpoints; a liveness probe restarts it after repeated failures. section 15.3
HTTP probes in a Deployment
Configure both probes against /healthz: readinessProbe runs every 5 seconds, while livenessProbe runs every 20 seconds. Apply the updated specification, watch the Pods, and refresh the application to observe traffic and restarts. section 15.3
How Learn Docker in a Month of Lunches, Second Edition covers it
How deep it goes
Explains HTTP, TCP, and command checks plus readiness and liveness actions, without detailing probe execution internals.
Examples
Uses an HTTP /healthz endpoint, five- and twenty-second intervals, Deployment YAML, kubectl apply, and Pod watching.
What it assumes
Assumes basic Kubernetes Deployment, Pod, and Service knowledge while defining probe types and failure effects directly.
What you can do after
Operate/configure Kubernetes Deployments with readiness and liveness probes, then verify Pod behavior using kubectl.
How it connects
Connects Kubernetes health checks with containers, Pods, Services, Deployments, and Docker HEALTHCHECK instructions.
Kubernetes for DevelopersA liveness or readiness probe is a Kubernetes health check that determines whether a container should be restarted or can receive traffic.
HTTPuses · HTTP is a standardized application-layer protocol that defines request-and-response messages for transferring resource representations between networked systems.
Kubernetesused by · Kubernetes is an open-source platform for orchestrating and automating the deployment, scaling, and management of containerized workloads across computing clusters.
curluses · curl is a command-line tool for transferring data to or from network resources using supported protocols; the name also refers to its transfer library, libcurl.
shell scriptuses · Bash is a Unix command-line shell and scripting language for executing commands interactively and through scripts.
liveness checkincludes · A liveness check is an automated health test that determines whether a running workload remains functional or should be restarted.
This explainer was generated by Manning's knowledge graph from the text of Learn Docker in a Month of Lunches, Second Edition. The section links point to the parts of the book it draws on.
