[HDDS-8931] Allow EC PipelineChoosingPolicy to be defined separately from Ratis

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Implemented
• Fix Version/s: 1.4.0
• Component/s: SCM
• Labels: pull-request-available
• Assignee: Stephen O'Donnell
• Reporter: Stephen O'Donnell
• Created: 26/Jun/23 14:28
• Updated: 27/Jun/23 11:58
• Resolved: 27/Jun/23 11:58

Description

Cluster may have set the PipelineChoosingPolicy to the HealthyPipelineChoosePolicy for Ratis, but it adds overhead and is not necessary for EC, as the EC pipeline is always healthy:

  public boolean isHealthy() {
    // EC pipelines are not reported by the DN and do not have a leader. If a
    // node goes stale or dead, EC pipelines will by closed like RATIS pipelines
    // but at the current time there are not other health metrics for EC.
    if (replicationConfig.getReplicationType() == ReplicationType.EC) {
      return true;
    }
    ...

To allow for flexibility, add a new config for the ECPipelineChoosingPolicy so it can be different from the Ratis policy.

Issue Links

• links to: GitHub Pull Request #4983