CLUSTER commands are not supported on Upstash: disable cluster mode in your client

TL;DR: CLUSTER commands are not supported on Upstash. Client-side clustering config against Upstash will fail. Fix - Disable cluster mode in your client. Configure regions in the console instead.

The fix

1. Disable cluster mode in your client. In ioredis, use a standalone Redis instance, not Cluster. In redis-py, use Redis, not RedisCluster.
2. Remove any cluster slots configuration or startup-node lists. Point the client at the single Upstash endpoint.
3. If you chose Upstash for multi-region reads, that is the Global database feature, not Redis Cluster. Configure regions in the console instead.

When to use this

• This covers exactly what the title says: CLUSTER commands are not supported on Upstash.
• You are setting this up for the first time, or auditing an existing setup.
• You want the key gotchas in one place before you start.

When not to use this

• You are doing a different workflow with CLUSTER; these steps are specific to the title above.
• You need the full reference docs; this is the short path, not the manual.

Compatibility

• Not pinned to a specific version; follows current CLUSTER behavior.

Verified against Upstash REST compatibility table: Cluster is marked not supported. Source: https://upstash.com/docs/redis/features/restapi