Support of kubernetes lifecycle hooks

What does this MR do?

Add support of kubernetes lifecycle hook

• preStop
• postStart

Why was this MR needed?

This MR is needed to allow execution of script at the start of the pod or before the stop of the pod

What's the best way to test this MR?

.gitlab-ci.yml

job:
  script:
  - ls -l /builds

Invalid hook configuration

config.toml

[[runners]]
  name = "kubernetes"
  url = "https://gitlab.com/"
  token = "TOKEN_HERE"
  executor = "kubernetes"
  [runners.kubernetes]
    image = "alpine:3.11"
    privileged = true
    namespace = "default"
    [runners.kubernetes.container_lifecycle.pre_stop.exec]
      command = []
    [runners.kubernetes.container_lifecycle.pre_stop.tcp_socket]
      port = 8080
      host = "localhost"

1. Run a job
2. The job fails with the following error

ERROR: Job failed (system failure): prepare environment: setting up build pod: Pod "runner-lr33aybb-project-24422682-concurrent-0dw4b6" is invalid: [spec.containers[0].lifecycle.preStop.exec.command: Required value, spec.containers[0].lifecycle.preStop.tcpSocket: Forbidden: may not specify more than 1 handler type, spec.containers[1].lifecycle.preStop.exec.command: Required value, spec.containers[1].lifecycle.preStop.tcpSocket: Forbidden: may not specify more than 1 handler type]. Check https://docs.gitlab.com/runner/shells/index.html#shell-profile-loading for more information

Log File

Log

Test postStart hook

config.toml

[[runners]]
  name = "kubernetes"
  url = "https://gitlab.com/"
  token = "TOKEN_HERE"
  executor = "kubernetes"
  [runners.kubernetes]
    image = "alpine:3.11"
    privileged = true
    namespace = "default"
    [runners.kubernetes.container_lifecycle.post_start.exec]
      command = ["touch", "/builds/postStart.txt"]

1. Run a job
2. The job succeeds and the file postStart.txt is listed as inside the /builds repository

Log File

Log

What are the relevant issue numbers?

closes: #3630 (closed)