[SPARK-46368] Support `readyz` in REST Submission API

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: Spark Core
• Labels: pull-request-available
• Assignee: Dongjoon Hyun
• Reporter: Dongjoon Hyun
• Created: 11/Dec/23 20:07
• Updated: 11/Jan/24 19:09
• Resolved: 11/Jan/24 19:09

Description

Like https://kubernetes.io/docs/reference/using-api/health-checks/, we need to provide `/readyz` API.

As a workaround, we can use the following.

readinessProbe:
  exec:
    command: ["sh", "-c", "! (curl -s http://localhost:6066/v1/submissions/status/none | grep -q STANDBY)"]

Issue Links

• links to: GitHub Pull Request #44692