{
  "schema_version": 2,
  "id": "develop/reference/errors/common/clusterdown",
  "title": "CLUSTERDOWN error",
  "url": "https://redis.io/docs/latest/develop/reference/errors/common/clusterdown/",
  "summary": "The cluster can't serve the command because a hash slot has no working node.",
  "tags": [
    "docs",
    "develop",
    "stack",
    "oss",
    "rs",
    "rc",
    "oss",
    "kubernetes",
    "clients"
  ],
  "last_updated": "2026-11-02T15:10:28+01:00",
  "page_type": "content",
  "content_hash": "7dbc427b542b47282bd02f1c0c98418b9635781040bf14898e2f98f27dc26841",
  "sections": [
    {
      "id": "overview",
      "title": "Overview",
      "role": "overview",
      "text": "A Redis cluster returns this error when it can't serve your command. The message has two versions:\n\n[code example]\n\n- `Hash slot not served` means that no node serves the key's hash slot. This happens when some slots were never assigned to a node, for example, in a cluster you haven't finished setting up.\n- `The cluster is down` means that the cluster is in a failed state. By default, a cluster stops serving commands when any hash slot has no working node. For example, this happens when a primary node fails and has no replica to take its place.\n\nIn redis-py, this error is `ClusterDownError: The cluster is down` or `ClusterDownError: Hash slot not served`."
    },
    {
      "id": "example",
      "title": "Example",
      "role": "example",
      "text": "After a primary with no replica fails, the other nodes stop serving commands, even for their own keys:\n\n[code example]"
    },
    {
      "id": "how-to-fix-it",
      "title": "How to fix it",
      "role": "content",
      "text": "1. Check the state of the cluster with [`CLUSTER INFO`](https://redis.io/docs/latest/commands/cluster-info). `cluster_state:fail` means the cluster is down. `cluster_slots_assigned` shows how many of the 16384 slots have a node.\n1. Find the failed nodes with [`CLUSTER NODES`](https://redis.io/docs/latest/commands/cluster-nodes). A failed node has `fail` in its flags.\n1. Bring the failed node back, or move its slots to working nodes. If slots were never assigned, assign them. `redis-cli --cluster create` assigns all the slots when it creates a cluster.\n\nTo keep the cluster working when a primary fails, give each primary at least one replica. A replica then takes its primary's place.\n\nTwo settings change what a cluster does when some slots have no working node:\n\n- `cluster-require-full-coverage no` lets nodes keep serving the slots that still have a working node.\n- `cluster-allow-reads-when-down yes` lets nodes serve reads while the cluster is in a failed state. Writes then get `CLUSTERDOWN The cluster is down and only accepts read commands`.\n\nSee [Redis Cluster configuration parameters](https://redis.io/docs/latest/operate/oss_and_stack/management/scaling#redis-cluster-configuration-parameters)."
    }
  ],
  "examples": [
    {
      "id": "overview-ex0",
      "language": "plaintext",
      "code": "CLUSTERDOWN Hash slot not served\nCLUSTERDOWN The cluster is down",
      "section_id": "overview"
    },
    {
      "id": "example-ex0",
      "language": "plaintext",
      "code": "> GET foo\n(error) CLUSTERDOWN The cluster is down",
      "section_id": "example"
    }
  ]
}