Added request trigger in plugins

[venkata-avinash-a]

Add request trigger plugin

Adds a new request trigger plugin that sends HTTP requests during node state transitions. Primary use case: managing Alertmanager silences automatically when nodes enter/exit maintenance.

Changes

File	Change
plugin/impl/request.go	New request trigger plugin
controllers/config.go	Register plugin in trigger registry

Features

• Body placeholder substitution: {{nodeName}}, {{state}}, {{startsAt}}, {{endsAt}}, {{silenceId}}
• Extracts Alertmanager silence ID from POST response and stores it as node label cloud.sap/alertmanager-silence-id

Example config

    # Create AlertManager silence when entering maintenance
    - type: request
      name: create_alertmanager_silence
      config:
        url: "https://alertmanager-internal.scaleout.qa-de-1.cloud.sap/api/v2/silences"
        method: "POST"
        body: '{"matchers": [{"name": "node", "value": "{{ "{{" }}nodeName{{ "}}" }}", "isRegex": false}, {"name": "region", "value": "{{ "{{" }}.Values.global.region{{ "}}" }}", "isRegex": false}, {"name": "service", "value": "ceph", "isRegex": false}, {"name": "severity", "value": "warning|info", "isRegex": true}, {"name": "support_group", "value": "storage", "isRegex": false}], "startsAt": "{{ "{{" }}startsAt{{ "}}" }}", "endsAt": "{{ "{{" }}endsAt{{ "}}" }}", "createdBy": "maintenance-controller", "comment": "Node {{ "{{" }}nodeName{{ "}}" }} entering maintenance"}'
    # Delete AlertManager silence when exiting maintenance
    - type: request
      name: delete_alertmanager_silence
      config:
        url: "https://alertmanager-internal.scaleout.qa-de-1.cloud.sap/api/v2/silence/{{ "{{" }}silenceId{{ "}}" }}"
        method: "DELETE"

QA validation (st1-qa-de-1)

• Node enters in-maintenance → silence created (HTTP 200), ID stored as label
• Node exits to operational → silence expired via DELETE (HTTP 200)
• qa_test.log

TODO

• Unit tests
• Documentation update in docs/plugins.md
• Customize request body via Helm values for per-cluster configuration
• Support group-level matchers for silencing alerts