Set up high availability

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This topic applies to Docker Enterprise.

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Docker Universal Control Plane is designed for high availability (HA). You can join multiple manager nodes to the cluster, so that if one manager node fails, another can automatically take its place without impact to the cluster.

Having multiple manager nodes in your cluster allows you to:

  • Handle manager node failures,
  • Load-balance user requests across all manager nodes.

Size your deployment

To make the cluster tolerant to more failures, add additional replica nodes to your cluster.

Manager nodes Failures tolerated
1 0
3 1
5 2

For production-grade deployments, follow these rules of thumb:

  • For high availability with minimal network overhead, the recommended number of manager nodes is 3. The recommended maximum number of manager nodes is 5. Adding too many manager nodes to the cluster can lead to performance degradation, because changes to configurations must be replicated across all manager nodes.
  • When a manager node fails, the number of failures tolerated by your cluster decreases. Don’t leave that node offline for too long.
  • You should distribute your manager nodes across different availability zones. This way your cluster can continue working even if an entire availability zone goes down.

Where to go next

ucp, high availability, replica