Pod Disruption Budgets

Pod Disruption Budgets (PDBs) ensure that a minimum number of pods remain available during voluntary disruptions such as node upgrades or evictions. Cosmopilot allows you to configure PDBs for validator and node groups within a ChainNodeSet.

Examples

spec:
  nodes:
    - name: fullnode
      instances: 3
      pdb:
        enabled: true
        minAvailable: 2   # optional, defaults to instances - 1
  validator:
    pdb:
      enabled: true
      minAvailable: 3    # meaningful only when other validators exist

With this configuration, Kubernetes will ensure that at least two fullnode pods remain running and, when multiple validators exist in the namespace, at least three validator pods stay available during maintenance operations.

Validator node groups

A node group with a validator block is configured from that block, so its PDB goes under nodes[].validator.pdb — not nodes[].pdb, which is ignored on such a group (Cosmopilot emits an admission warning when you set it there):

spec:
  nodes:
    - name: validators
      instances: 3
      validator:
        pdb:
          enabled: true
          minAvailable: 2   # optional, defaults to instances - 1

This creates a PDB named <nodeset>-<group>-validator selecting only that group's validator pods.

You may also instruct Cosmopilot to ignore group labels on PDB checks. This is useful to ensure no downtime globally or per global ingress, instead of just per group.

  ingresses:
  - name: fullnodes
    groups:
    - fullnode-a
    - fullnode-b

...

  nodes:
    - name: fullnode-a
      instances: 3
      ignoreGroupOnDisruptionChecks: true      
      pdb:
        enabled: true
    - name: fullnode-b
      instances: 3
      ignoreGroupOnDisruptionChecks: true      
      pdb:
        enabled: true

Notes

• PDBs are currently supported only on ChainNodeSet resources.
• minAvailable defaults to the number of instances minus one for node groups.
• On a node group with a validator block, use nodes[].validator.pdb. A group-level nodes[].pdb creates no PDB there.
• ignoreGroupOnDisruptionChecks has no effect on a validator group: validator pods already coordinate disruptions chain-wide, across every nodeset and group.
• A validator PDB only has an effect when multiple validators run in the same namespace; otherwise the default minAvailable: 0 leaves it ineffective.
• During upgrades, PDBs are automatically disabled for ChainNodes with the Upgrading status.