Advanced customisations

kora provisions a fixed set of Kubernetes resources for each agent type. Most teams never change them. When your cluster needs something kora does not set, such as a node pool, a storage class or an image pull secret, you can patch those resources without forking kora.

This guide walks through writing a manifest patch, previewing the result and deploying it. It assumes kora is already installed. See Deploying kora for the install.

What you can patch

kora-agents applies your patches to the StatefulSet, workspace PersistentVolumeClaim, Service, ServiceAccount, HPA, PDB and sandbox Pod it provisions for each agent type. Patches apply to every tenant that shares the kora-agents pod.

Each patch is one kustomize patches: entry with a target.kind. Both strategic merge patches and JSON6902 patches work, and the entry accepts the usual selectors.

Some fields stay platform-owned. A patch that changes a resource's identity, its security context or the sandbox workspace mount is rejected when kora-agents starts.

Write a patch

Patches are values under agents.manifestPatches in your Helm values. Each key is one patch. Keys sort into apply order, so prefix them with a number.

This patch pins agent pods to a node pool:

yaml

agents:
  manifestPatches:
    50-nodeselector:
      target:
        kind: StatefulSet
      patch: |
        apiVersion: apps/v1
        kind: StatefulSet
        metadata:
          name: any
        spec:
          template:
            spec:
              nodeSelector:
                disktype: ssd

Settings in agents.workloads and agents.workspace apply before manifest patches. When both set a field, the patch wins. Prefer those settings when they cover your need, and use a patch for the rest.

Preview the result

Before you deploy, render the exact YAML kora-agents would produce. The -render mode needs no cluster or database.

bash

cd backend
go run ./cmd/kora-agents -render \
  -patch-dir=/path/to/patches \
  -agent-slug=coder \
  -namespace=tenant-example \
  -sandbox

• -patch-dir: directory of *.yaml or *.yml patch files. Write each agents.manifestPatches key as a file named <key>.yaml in this directory, holding that key's entry. It mirrors what the Helm chart mounts at /etc/kora/manifest-patches.
• -agent-slug: required, the agent type slug to render.
• -agent-type-id: the agent type's ID, for patches that select on the runkora.io/agent-type label. Defaults to render-<slug>.
• -namespace: tenant namespace to render into. Defaults to tenant-example.
• -sandbox: also render a sample sandbox Pod.

An invalid patch fails immediately with the offending filename. That covers a missing or unknown target kind, a patch kustomize cannot apply, a field typo and a change to a protected field. It is the same validation kora-agents runs at startup.

To confirm the API server accepts every rendered object, pipe the output through kubectl apply --dry-run=server -f - against a non-production cluster.

The preview omits metadata.ownerReferences. The runtime resolves those from a live lookup of the tenant resource, which -render has no cluster to query. Every field a patch could reach is otherwise faithful to what kora-agents creates.

Deploy the patch

Set agents.manifestPatches in your values and upgrade the release. The chart writes each patch into the kora-agents-manifest-patches ConfigMap and rolls the kora-agents pod. Patches load once at startup, so a change takes effect on that roll.

If a patch fails to load, kora-agents fails to start and the error names the file. Fix the patch and upgrade again.

Migrate from environment variable overrides

Older installs set KORA_MANIFEST__<Kind>__<name>__<path> environment variables on the kora-agents pod. These are no longer read. kora-agents logs a warning at startup for each one it finds. Move each override into a patch under agents.manifestPatches, then remove the variable.

References

• Manifest patches: why kora uses kustomize patches and which fields stay protected.
• First-class workload placement: the agents.workloads settings that apply before patches.
• K8s manifest overrides via environment variables: the superseded mechanism.