Rebalance

Activating a New Topology Rebalance​

This API call is for rebalancing to a new topology.

Description​

URI​

/rebalance/activate/<hash>

Method​

POST

Inputs​

• hash : The hash of the new topology after the rebalance.

Examples​

curl -X POST \
  http://127.0.0.1:8112/rebalance/activate/0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef

In this example:

• activate : This is the command to activate a new topology rebalance.

• 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef : This is the hash for the transition.

Getting Topology Rebalance State​

This API call is for viewing the current topology rebalance state.

Data will be returned as a JSON document. The fields in this document are described below.

Description​

URI​

/rebalance/state

Method​

GET

Output​

• current : The current topology in which this node resides.

• next : The next topology for this node.

• state : Current rebalance state for this node. Value is one of:

  • TOPO_REBALANCE_IDLE (no rebalance activity)

  • TOPO_REBALANCE_VOTE (establishing agreement on next hash across the cluster)

  • TOPO_REBALANCE_REHASH (relocating data)

  • TOPO_REBALANCE_REHASH_VOTE (waiting for data relocation completion on all nodes)

  • TOPO_REBALANCE_CLEANUP (removing data from old topology)

  • TOPO_REBALANCE_COMPLETE (local operations complete, switching to next topology)

  • TOPO_REBALANCE_COMPLETE_VOTE (waiting for all other nodes to complete and switch to the next topology)

During a rebalance operation, each node will proceed through the above states in order, returning to TOPO_REBALANCE_IDLE when finished. The topology that was listed as "next" is now "current", and "next" is now "-", meaning no next topology.

Examples​

curl http://127.0.0.1:8112/rebalance/state

Example 1 Output​

{
  "current": "071b9fe756e07a8656273546d504dbc69c356c9ed525aacf898e3cceb3778755",
  "next": "8bd44d5240847b8aa67435492d0b93e334ee6e3725afe02ee83821aee60b803f",
  "state": "TOPO_REBALANCE_COMPLETE"
}

Abort the Current in Progress Topology Rebalance​

This API call is for aborting the current rebalancing to a new topology.

4Description​

URI​

/rebalance/deactivate/<hash>

Method​

POST

Inputs​

• hash : The hash of the new topology after the rebalance.

Examples​

curl -X POST \
  http://127.0.0.1:8112/rebalance/deactivate/0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef

In this example:

• deactivate : This is the command to activate a new topology rebalance.

• 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef : This is the hash for the transition.