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Cordon Pools

Overview​

Pool Cordon allows you to temporarily prevent new replicas, snapshots, restores, or imports from being scheduled on a specific Replicated PV Mayastor pool. Use cordon during planned maintenance, hardware investigations, or controlled decommissioning. Existing data remains fully available and unaffected until explicitly migrated or removed.

Requirements​

You can configure the maximum pool size using the maxExpansion field in the DiskPool CR.

  • Replicated PV Mayastor deployment with a version that supports pool cordoning

  • kubectl-mayastor or kubectl-openebs plugin installed and configured with appropriate administrative access

Cordon a Pool​

When you cordon a pool, specify the resource types you want to block by including their flags. A flag’s presence sets that resource type to true (cordoned). If you omit a flag, that resource type remains uncordoned (false).

Cordon a pool to block new replicas and imports using kubectl-openebs. For Example: kubectl-openebs mayastor

Cordon a Pool to Block New Replicas and Imports

kubectl-openebs mayastor cordon pool <pool-name> --replicas
kubectl-openebs mayastor cordon pool <pool-name> --replicas --imports

Flags

  • --replicas - Prevent new replicas from being created on the pool
  • --snapshots - Prevent new snapshots from being scheduled
  • --restores - Prevent new restore operations on the pool
  • --imports - Prevent pool import operations.

Uncordon a Pool​

When you uncordon a pool, you remove the scheduling restrictions and allow new resources to be created again. Use this when maintenance is complete or when you want the pool to resume normal operations.

Uncordon a Pool and Re-enable All Resource Scheduling

kubectl-openebs mayastor uncordon pool <pool-name> --replicas --imports

Flags

  • The same flags apply as with cordon, letting you selectively enable scheduling for replicas, snapshots, restores, and imports.
  • By default, running uncordon pool without flags will remove all existing cordons, restoring full scheduling for the pool.

Typical Use Cases​

  • Planned Maintenance: Isolate a pool before firmware upgrades or hardware replacement.
  • Capacity Management: Prevent new replicas on a pool nearing its operational threshold.
  • Controlled Decommissioning: Cordon, migrate replicas, and then retire the pool.
note
  • Cordoning blocks new resources only. It does not move or delete existing data.
  • Make sure enough other pools remain uncordoned to keep volumes healthy.
  • Pools stay cordoned across restarts until you explicitly uncordon them.