CLUSTER ADDSLOTS

Syntax text Syntax diagram API methods

CLUSTER ADDSLOTS slot [slot ...]

Client: Python (redis-py) Node.js (node-redis) Java-Sync (Jedis) Lettuce-Sync Java-Async (Lettuce) Java-Reactive (Lettuce) Go (go-redis) C#-Sync (NRedisStack) C#-Async (NRedisStack) PHP (Predis) Rust-Sync (redis-rs) Rust-Async (redis-rs)

No method signature available for this client.

parseCommand(
    parser: CommandParser,  // The Redis command parser
    slots: number | Array<number>  // One or more hash slots to be assigned
) → SimpleStringReply<'OK'>

clusterAddSlots(
    slots: int...
) → String  // OK

clusterAddSlots(
    slots: int...  // One or more hash slots to be assigned
) → String  // OK

clusterAddSlots(
    slots: int...  // One or more hash slots to be assigned
) → RedisFuture<String>  // OK

clusterAddSlots(
    slots: int...  // One or more hash slots to be assigned
) → Mono<String>  // OK

ClusterAddSlots(
    ctx: context.Context,
    slots: ...int
) → *StatusCmd

No method signature available for this client.

No method signature available for this client.

No method signature available for this client.

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No method signature available for this client.

Available since:

Redis Open Source 3.0.0

Time complexity:

O(N) where N is the total number of hash slot arguments

ACL categories:

@admin, @slow, @dangerous,

Compatibility:

Redis Software and Redis Cloud compatibility

This command is useful in order to modify a node's view of the cluster configuration. Specifically it assigns a set of hash slots to the node receiving the command. If the command is successful, the node will map the specified hash slots to itself, and will start broadcasting the new configuration.

However note that:

1. The command only works if all the specified slots are, from the point of view of the node receiving the command, currently not assigned. A node will refuse to take ownership for slots that already belong to some other node (including itself).
2. The command fails if the same slot is specified multiple times.
3. If one of the specified slots is marked as importing, Redis clears that temporary state after the node assigns the previously unbound slot to itself. At that point, the slot belongs to the node, so it is no longer being imported.

Required arguments

Examples

The following command assigns slots 1, 2, and 3 to the node receiving the command:

> CLUSTER ADDSLOTS 1 2 3
OK

If you try to execute the same command again on the same node, Redis will return an error because the slots are already assigned:

> CLUSTER ADDSLOTS 1 2 3
ERR Slot 1 is already busy

Details

Usage in Redis Cluster

This command only works in cluster mode and is useful in the following Redis Cluster operations:

1. To create a new cluster ADDSLOTS is used in order to initially setup master nodes splitting the available hash slots among them.
2. In order to fix a broken cluster where certain slots are unassigned.

Information about slots propagation and warnings

Note that once a node assigns a set of slots to itself, it will start propagating this information in heartbeat packet headers. However the other nodes will accept the information only if they have the slot as not already bound with another node, or if the configuration epoch of the node advertising the new hash slot, is greater than the node currently listed in the table.

This means that this command should be used with care only by applications orchestrating Redis Cluster, like redis-cli, and the command if used out of the right context can leave the cluster in a wrong state or cause data loss.

Redis Software and Redis Cloud compatibility

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