Is there a way to get a trigger to shutdown, so we can close all connections gracefully before shutdown and don't proceed any actions after that probe and keeping the probe ready to kill.
This including flushing logs, keeping any state of the application saved before handing over to the new pod and many more use cases.
You have 2 options:
Containers (PID 1) receive SIGTERM before the container (and the pod) is removed. You can trap SIGTERM and act on it.
You can use the preStop lifecycle hook
Important implementation details can be found here: https://kubernetes.io/docs/concepts/workloads/pods/pod/#termination-of-pods
apiVersion: v1
kind: Pod
metadata:
name: prestop-pod
spec:
terminationGracePeriodSeconds: 5
containers:
- name: nginx
image: nginx
lifecycle:
preStop:
httpGet:
# only port is reqired
port: 80
path: "?preStop"
# scheme: HTTP
# host: ...
# httpHeaders:
# name: ...
# value: ...After kubectl apply -f on this file, run kubectl log -f prestop-pod while executing kubectl delete pod prestop-pod on another terminal. You should see something like:
$ kubectl apply -f prestop.yaml
pod/prestop-pod created
$ kubectl logs -f prestop-pod
10.244.0.1 - - [21/Mar/2019:09:15:20 +0000] "GET /?preStop HTTP/1.1" 200 612 "-" "Go-http-client/1.1" "-"