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Custom Patches

You can use custom patches to use the full power of Kubernetes patches to modify your sandboxed workloads. Any valid patch can be used and it will be applied on top of the baseline workload to derive the forked workload.

Using a different update strategy for forked Deployments​

By default, forked Deployments are created with an Recreate update strategy to enable fast updates to the sandboxes. Below is an example custom patch that sets the forked workload to use the RollingUpdate update strategy.

name: rolling-update-sandbox
spec:
  description: Sandbox with Deployment overriding default Recreate strategy
  cluster: ...
  forks:
  - forkOf:
      kind: Deployment
      name: route
      namespace: hotrod
    customizations:
      images:
      - image: ...
      patch:
          type: strategic
          value: |
            spec:
              strategy:
                type: RollingUpdate

Specifying a custom ImagePullSecret for the forked Deployment​

The following example shows how you can specify a custom registry just for the sandboxed (forked) Deployment using a strategic merge patch.

name: custom-registry-sandbox
spec:
  description: sandbox with custom imagepullsecret
  cluster: ...
  forks:
  - forkOf:
      kind: Deployment
      name: route
      namespace: hotrod
    customizations:
      - image: ...
      patch:
          type: strategic
          value: |
            spec:
              template:
                spec: 
                   imagePullSecrets:
                    - name: regcred

Customizing Kubernetes Labels on Sandbox Pods​

For customizing Kubernetes Labels on sandbox pods, you must first allow that label to be present on the sandbox pods by adding them to the allow-list from settings > preserved labels in the Signadot Dashboard.

It is important to avoid specifying labels on sandbox pods that match the selectors of baseline Kubernetes services, as this can cause sandbox pods to be included in unintended service routing.

name: custom-label-sandbox
spec:
  description: sandboxed pod with custom label
  cluster: ...
  forks:
  - forkOf:
      kind: Deployment
      name: route
      namespace: hotrod
    customizations:
      - image: ...
      patch:
          type: strategic
          value: |
            spec:
              template:
                metadata:
                  labels: 
                    test-label: "true"

Customizing Kubernetes Annotations on Sandbox Pods​

The following example shows how you can customize the Kubernetes annotations for a sandboxed workload pod using a strategic merge patch. Unlike labels, there are no restrictions on this operation.

name: custom-annotation-sandbox
spec:
  description:  sandboxed pod with custom annotation
  cluster: ...
  forks:
  - forkOf:
      kind: Deployment
      name: route
      namespace: hotrod
    customizations:
      - image: ...
      patch:
          type: strategic
          value: |
            spec:
              template:
                metadata:
                  annotations:
                    test-annotation: "true"