karpenter_config

Description

The karpenter_config parameter provides a JSON escape hatch for the Karpenter workload NodePool and its EC2NodeClass. Use this to access Karpenter API features not exposed as individual parameters, such as several disruption windows, a per-reason budget cap, or advanced block device mappings.

A single recurring disruption window is karpenter_disruption_block_schedule and karpenter_disruption_block_duration, and pinning the AL2023 AMI version is karpenter_ami_alias. Both reach the build and custom pools, which karpenter_config does not. Reach for karpenter_config for what those parameters cannot express.

Individual karpenter_* parameters build the defaults. karpenter_config overrides them at the section level. For example, setting nodePool.template.spec.requirements in the config completely replaces the defaults built from karpenter_instance_families, karpenter_instance_sizes, etc.

Default Value

The default value is empty (no overrides).

Setting the Parameter

Using a JSON string:

$ convox rack params set karpenter_config='{"nodePool":{"disruption":{"budgets":[{"nodes":"10%"},{"nodes":"0","schedule":"0 9 * * mon-fri","duration":"8h"}]}}}' -r rackName
Updating parameters... OK

Using a JSON file:

$ convox rack params set karpenter_config=/path/to/karpenter-config.json -r rackName
Updating parameters... OK

Additional Information

• Input formats: Raw JSON string, base64-encoded JSON, or a .json file path. Maximum 64KB.
• Allowed top-level keys: nodePool and ec2NodeClass only.
• Protected fields that cannot be overridden: ec2NodeClass.role, ec2NodeClass.instanceProfile, ec2NodeClass.subnetSelectorTerms, ec2NodeClass.securityGroupSelectorTerms, nodePool.template.spec.nodeClassRef, nodePool.template.metadata.labels["convox.io/nodepool"], ec2NodeClass.tags.Name, ec2NodeClass.tags.Rack.
• amiSelectorTerms replaces the generated selector. Setting ec2NodeClass.amiSelectorTerms for any reason, not only to pin an AMI, takes the workload pool out of karpenter_ami_alias, which no longer reaches that pool. The build and additional pools stay pinned.
• amiSelectorTerms and userData suppress the kubelet registry settings. Setting either one suppresses kubelet_registry_pull_qps and kubelet_registry_burst on the workload pool, each on its own, because both replace the generated NodeConfig. The build and additional pools do not read karpenter_config and keep those settings.
• See the Karpenter feature page for the full JSON structure, available fields, and examples.

See Also

• Karpenter for the full Karpenter configuration reference
• additional_karpenter_nodepools_config for creating custom NodePools
• karpenter_disruption_block_schedule for a recurring no-disruption window on every pool
• karpenter_disruption_block_duration for how long that window stays open
• karpenter_ami_alias for pinning the AL2023 AMI version on every pool