CLUSTER

Syntax

CLUSTER

Time complexity: Depends on subcommand.

ACL categories: @slow

This is a container command for cluster introspection commands. Cluster-aware clients use them to find out which nodes serve which hash slots.

Cluster mode is off by default. CLUSTER works only when Dragonfly is started with --cluster_mode set to emulated or yes. Otherwise, every subcommand returns ERR Cluster is disabled. Enabled via passing --cluster_mode=emulated|yes. INFO cluster reports cluster_enabled:1 when cluster mode is on and cluster_enabled:0 when it is off.

• --cluster_mode=emulated: the node presents itself as a single-shard cluster that owns all 16384 hash slots. On a master, the topology replies also list the replicas connected to it (with --managed_service_info, only to connections on the admin port). On a replica, they list its master and the replica itself.
• --cluster_mode=yes: the topology comes from the configuration that the node receives with DFLYCLUSTER CONFIG. Until then, CLUSTER NODES, CLUSTER SHARDS, CLUSTER SLOTS and commands that access keys return ERR Cluster is not yet configured, and CLUSTER INFO reports cluster_state:fail.

See Cluster Mode for how to set up either mode.

Currently, the following subcommands are supported:

• CLUSTER HELP
• CLUSTER INFO
• CLUSTER KEYSLOT
• CLUSTER MYID
• CLUSTER NODES
• CLUSTER SHARDS
• CLUSTER SLOTS

CLUSTER HELP describes only SLOTS, NODES, INFO and HELP, although all of the subcommands above work.

Dragonfly nodes do not exchange cluster state over a cluster bus, and slots are assigned with DFLYCLUSTER CONFIG. The other Valkey subcommands, such as CLUSTER ADDSLOTS, CLUSTER MEET, CLUSTER FAILOVER, CLUSTER RESET, CLUSTER COUNTKEYSINSLOT, CLUSTER GETKEYSINSLOT, CLUSTER LINKS and CLUSTER MYSHARDID, are not implemented. They return an unknown-subcommand error, or a wrong-number-of-arguments error when called with arguments.

Examples

Dragonfly started without --cluster_mode:

dragonfly> CLUSTER MYID
(error) ERR Cluster is disabled. Enabled via passing --cluster_mode=emulated|yes

Subcommands that Dragonfly does not implement, with --cluster_mode=emulated:

dragonfly> CLUSTER MYSHARDID
(error) ERR Unknown subcommand or wrong number of arguments for 'MYSHARDID'. Try CLUSTER HELP.
dragonfly> CLUSTER COUNTKEYSINSLOT 7000
(error) ERR wrong number of arguments for 'cluster countkeysinslot' command