override-device-registry

Override image with image stream

This is an example on how to use images from image streams, instead of directly pulling from quay.io or Docker Hub. It also works with OpenShift builds, as long as you can build the image in the same way on the cluster.

The following example will replace the iot-device-registry-jdbc image. It uses ImageStreams and a build with the S2I Java image.

Deploy

Create the ImageStream and S2I build. Be sure point the build to the Git repository you want to build from:

oc apply -f .

This creates the image stream for the S2I image and for the image being built by the BuildConfig. Once the build populated the image stream, you can override the image.

Note: The image stream is configured to "hijack" local, unqualified image names and replace them with the internal registry image.

Image trigger

You can set an image trigger for the deployment/stateful set as well:

oc set triggers deployment/iot-device-registry --from-image=iot-device-config-jdbc:latest --containers device-registry

Note: This only works if the annotations of the deployment do not get overwritten by any operator.

Override

Afterwards you need to override the image name of the container you want to replace, with an unqualified image name, e.g. iot-device-registry-jdbc:latest instead of quay.io/ctron/iot-device-registry-jdbc:latest.

There are different ways, with different pros/cons.

For deployments not deployed by any operator, like the enmasse-operator, you must directly modify the deployment.

Override using imageOverrides

Edit the IoTConfig and override the image:

apiVersion: iot.enmasse.io/v1alpha1
kind: IoTConfig
metadata:
  name: default
spec:
  imageOverrides:
    iot-device-registry-jdbc:
      name: iot-device-registry-jdbc:latest

From what I know, this currently works only with the IoTConfig. However it is easy to override, and remove later on.

Override using env-vars

The deployment of the enmasse-operator has a bunch of environment variables, which override the built in image map.

It is possible to override the image by setting the appropriate environment variable.

oc set env dc enmasse-operator IOT_DEVICE_REGISTRY_JDBC_IMAGE=iot-device-registry-jdbc:latest

Theoretically you could remove the override later on by executing:

oc set env dc enmasse-operator IOT_DEVICE_REGISTRY_JDBC_IMAGE-

However, the default deployment of EnMasse sets all environment variables by default, to override the internal image map, which sometimes contains wrong values. So clearing the environment variable isn't a safe approach. You need to record the original value and set this later to remove the override.

This approach works for all images deployed by the enmasse-operator.