Chapter 8. Triggering updates on image stream changes

OpenShift Container Platform deployment configurations and build configurations can be automatically triggered by changes to image stream tags. The triggered action can be run using the new value of the image referenced by the updated image stream tag.

Kubernetes resources do not have fields for triggering, unlike deployment and build configurations, which include as part of their API definition a set of fields for controlling triggers. Instead, you can use annotations in OpenShift Container Platform to request triggering.

The annotation is defined as follows:

apiVersion: v1
kind: Pod
metadata:
  annotations:
    image.openshift.io/triggers:
      [
       {
         "from": {
           "kind": "ImageStreamTag", 

           "name": "example:latest", 

           "namespace": "myapp" 

         },
         "fieldPath": "spec.template.spec.containers[?(@.name==\"web\")].image", 

         "paused": false 

       },
      # ...
      ]
# ...

When one of the core Kubernetes resources contains both a pod template and this annotation, OpenShift Container Platform attempts to update the object by using the image currently associated with the image stream tag that is referenced by trigger. The update is performed against the

fieldPath

Examples of core Kubernetes resources that can contain both a pod template and annotation include:

When adding an image trigger to deployments, you can use the

oc set triggers

example

example:latest

web

image.openshift.io/triggers