[IGNITE-18741] Implement PD-side logic for an initialization phase of group lease management

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Labels: iep-101 ignite-3
• Epic Link: Placement Driver [Part 1]
• Assignee: Vladislav Pyatkov
• Reporter: Alexander Lapin
• Created: 07/Feb/23 12:44
• Updated: 18/May/23 08:42
• Resolved: 09/Mar/23 14:47

Description

Motivation

There are two phases of lease management:

• initialization - new leases management. // marked with greed
• maintenance - already existing leases management. // marked with orange

Given ticket is about new leases management on the placement driver side(the active actor one). So it covers the flow from the detection of a replication group appearance in the logical topology to sending leaseGrant message to the primary replica candidate.

Definition of Done

1. All triggers related to new primary replica candidate appearance are covered.
2. Placement driver starts primary replica candidate promotion event loop.

Implementation Notes

1.Following events should be considered as triggers related to new primary replica candidate appearance:

• MetaStorage based logical topology updates. We use  MS and not CMG events here in order to linearize logical topology updates with other configuration events. Please pay attention that DistributionZone logic is responsible for population ms with logical topology, following key DISTRIBUTION_ZONE_LOGICAL_TOPOLOGY_KEY is used and yep we may rename it.
• Replication group assignment updates.

As usual, we should first register listeners and then initialize the flow according to already existing assignments and logical topology.

2. Following steps inside primary replica candidate promotion event loop are expected

UPD:
During implementation, the issue was reformulated and slightly redesigned. By the redesign result, a class diagram was drawn.

Issue Links

• links to: GitHub Pull Request #1726