Implement cos-agent integration

[mateoflorido]

Overview

Implement the cos-agent integration for k8s and k8s-worker charms.

Rationale

This pull request introduces an implementation for integrating our charms with the Canonical Observability Stack. In this first version, we demonstrate the capabilities of sending scrape jobs to Prometheus over relation data for the following Kubernetes components:

1. Kubernetes Control Plane (k8s):
   • Kube API Server
   • Kube Controller Manager
   • Kube Proxy
   • Kube Scheduler
   • Kubelet
     • cAdvisor
     • Probes
   • Kube State Metrics
2. Kubernetes Worker (k8s-worker):
   • Kubelet
     • cAdvisor
     • Probes
   • Kube Proxy

This initial version of the integration relies on manual testing. Integration tests will be introduced in future PRs.

Module Changes

• Introduced a new TokenDistributor module to generalize token distribution for the cluster and cos-tokens relations.
• Introduced a COSIntegration helper class to generate Prometheus scrape jobs for the Kubernetes components.

Library Changes

• Added cos-agent library.
• Added cosl package.

[github-actions]

license-eye has totally checked 57 files.

Valid	Invalid	Ignored	Fixed
13	5	39	0

Click to see the invalid file list

• charms/worker/k8s/lib/charms/grafana_agent/v0/cos_agent.py
• charms/worker/k8s/src/cos_integration.py
• charms/worker/k8s/src/token_distributor.py
• charms/worker/k8s/templates/cos_roles.yaml
• charms/worker/k8s/templates/ksm.yaml

[addyess]

I ❤️ token_distributor. We can work with this!