Description
- We understand that liveness probes and the way they assist keep our apps healthy by ensuring unhealthy containers are restarted automatically. Same as liveness probes, Kubernetes permit us to also define a readiness looked for our pod.
- The readiness probe is deployed periodically and examines whether the precise pod should receive client requests or not.
- Whenever a container’s readiness probe returns back success, it’s signaling that the container is ready to simply accept requests.
- This notion of being prepared is clearly something that’s specific to every container.
- Almost as liveness probe Kubernetes sends requests to container and supported the result either successful or unsuccessful response it decides container is prepared to require traffic or still preparing for that.
- The liveness probes not like, if a container fails the readiness check, it won’t be killed or restarted.
- This is a very good practice to always add a readiness probe even it’s the simplest app within the container.
Readiness Probe Types
There are three sorts of Readiness Probe.
1.HTTP GET
- This type of probe conveyed a request on the container’s IP address, a port, and path we specify.
- The Probe is always taken into account a failure and containers are going to be treated as not ready and no traffic will get diverted thereto.
2. TCP SOCKET
- TCP Socket probe struggles to open a TCP connection to the required port of the container.
- If the connection is built successfully, the container would be marked as ready and it’ll receive traffic.
- Kubernetes is another case that will wait and run the probe to see the status again.
3. EXEC Probe
- The EXEC probe executes some commands you provide inside the container and checks the command’s exit status code.
- The probe is successful if the status code is 0.
- All other codes are considered failures.
Readiness Probe Examples
my-rn-exec.yaml
Kind: Pod apiversion: v1 metadata: name: myapp-rn-exc Spec: Containers: -name: my app image: ahmedmansoor/hi Ports: -containerPort: 80 Readiness Probe: exec: command: -ls -/tmp/ready
my-rn-tcp.yaml
Kind: Pod apiversion: v1 metadata: name: myapp-rn-tcp Spec: Containers: -name: my app image: ahmedmansoor/hi Ports: -containerPort: 80 Readiness Probe: tcpSocket Port : 8080
my-rn-http.yaml
Kind: Pod apiversion: v1 metadata: name:myapp-rn-http Spec: Containers: -name: my app image: ahmedmansoor/hi Ports: -containerPort:80 Readiness Probe: http Get: Port: 80 path:/
