[extension/leader elector] Initial implementation for the extension leader elector

[rakesh-garimella]

Description

This extension could be used to run multiple receivers in HA mode. The receiver which has successfully acquired the lease becomes active and thus becomes leader.

The extension uses k8s.io/client-go/tools/leaderelection to perform leader election. The component that owns the lease becomes the leader and runs the function defined in onStartedLeading. If the leader loses the lease, it runs the function defined in onStoppedLeading, stops its operation, and waits to acquire the lease again.

The config would like this:

receivers:
  my_awesome_reciever:
    leader_elector: leader_elector
exporters:
  debug:
    verbosity: detailed
extensions:
  leader_elector:
    auth_type: kubeConfig
    lease_name: foo
    lease_namespace: default

service:
  extensions: [leader_elector]
  pipelines:
    metrics:
      receivers: [my_awesome_receiver]
      exporters: [debug]
  telemetry:
    logs:
      level: debug

Note: The receiver requires to be modified in order to support this extension.

Link to tracking issue

Fixes
#34460

Testing

Unit tests have been implemented.

Documentation

Readme doc has been added.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: rakesh-garimella / name: Rakesh Garimella (48bb3a1, cde9c4c, a80a36f, 2074ef4, e9ddfe0, 1cda019, 0b57a6c, 86e2633, d0cda8b, 444878b, c450547, f37f1de, 420968e, ab29ff9, 7764805)

[JaredTan95]

One question, does this extension work for all receivers? Does the receiver need to be modified?

[rakesh-garimella]

One question, does this extension work for all receivers? Does the receiver need to be modified?

Hi @JaredTan95 the receiver needs to be modified to be able to support this extension.

[JaredTan95]

It would be better to give a rolebingding example about the lease that serviceaccount needs to bind with ClusterRoleBinding ClusterRole.

See the example in Kubernetes Events Receiver: https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/receiver/k8seventsreceiver#rbac

[atoulme]

Please secure a sponsor for this component.