Maintenance mode

In this mode, the node is not reachable from the outside, i.e.

• it refuses all incoming RPC connections,

• it does not join the cluster, thus

  • all operations that need synchronizing with other nodes are disabled (e.g. schema changes),
  • all cluster-wide operations are disabled for this node (e.g. repair),
  • other nodes see this node as dead,
  • cannot read or write data from/to other nodes,

• it does not open Alternator transport ports and the TCP CQL port.

The only way to make CQL queries is to use :doc:the maintenance socket </operating-scylla/admin-tools/maintenance-socket/>. The node serves only local data.

To start the node in maintenance mode, use the --maintenance-mode true flag or set maintenance_mode: true in the configuration file.

REST API works as usual, but some routes are disabled:

• authorization_cache
• failure_detector
• hinted_hand_off_manager