ZooKeeper

1. Coordinator leader election
2. Segment “publishing” protocol from
3. Overlord leader election
4. and MiddleManager task management

We use the Curator LeadershipLatch recipe to do leader election at path

The and are used for this.

Which signifies that they exist. They will also subsequently create a permanent znode at

And as they load up segments, they will attach ephemeral znodes that look like

The is used for this.

When the decides that a Historical process should load or drop a segment, it writes an ephemeral znode to