Adding a doc for developing operator images

Signed-off-by: Varad Ahirwadkar <[email protected]>

Author: varad-ahirwadkar

docs/Developers-guide.md

@@ -0,0 +1,83 @@
+# Building the RSCT Images
+### Export Environment Variables
+Before building the images, export the necessary environment variables if reuired.  
+For example:
+```
+# Registry where images will be pushed
+# Default value is ghcr.io/ocp-power-automation/rsct-operator
+export IMAGE_TAG_BASE=ghcr.io/ocp-power-automation/rsct-operator
+
+# Current version of the operator to build
+# Default value is set to the current released version at the ghcr.io/ocp-power-automation/rsct-operator registry
+export VERSION=0.0.1-alpha3
+
+# Set the pervious version to the latest released operator version
+# Default value is set to the pervious released version at the ghcr.io/ocp-power-automation/rsct-operator registry
+export PREVIOUS_VERSION=0.0.1-alpha2
+
+# Container tool (docker or podman)
+# Default is set to podman
+export CONTAINER_TOOL=docker
+
+# To use a different registry for adding multiple operators in the new catalog source index, export the new registry and set the correct PREVIOUS_VERSION
+# Default value is ghcr.io/ocp-power-automation/rsct-operator
+export PREVIOUS_IMAGE_TAG_BASE=ghcr.io/ocp-power-automation/rsct-operator
+```
+
+### Update the Catalog Index
+Before building the catalog, update the index `entries` in *catalog/index.yaml*. Ensure all `entries` match the `bundles` available in the catalog source.
+
+For example, if you are building the following version:
+```
+export VERSION=0.0.1-alpha3
+export PREVIOUS_VERSION=0.0.1-alpha2
+```
+Add the new entry for `VERSION=0.0.1-alpha3` in *catalog/index.yaml*:
+```
+  - name: rsct-operator.v0.0.1-alpha3
+    replaces: rsct-operator.v0.0.1-alpha2
+```
+After adding the new version, the `entries` in [catalog/index.yaml](https://github.com/ocp-power-automation/rsct-operator/blob/main/catalog/index.yaml) will look like this:
+```
+---
+schema: olm.channel
+package: rsct-operator
+name: alpha
+entries:
+  - name: rsct-operator.v0.0.1-alpha0
+  - name: rsct-operator.v0.0.1-alpha1
+    replaces: rsct-operator.v0.0.1-alpha0
+  - name: rsct-operator.v0.0.1-alpha2
+    replaces: rsct-operator.v0.0.1-alpha1
+  - name: rsct-operator.v0.0.1-alpha3
+    replaces: rsct-operator.v0.0.1-alpha2
+```
+**Note:**
+Before pushing the images, make sure you are logged in to the registry:
+```
+docker login <registry>
+```
+
+## Building and Pushing Images
+1. Build and push the operator image
+
+**Single architecture image (ppc64le)**  
+```
+make docker-build docker-push
+```
+
+**Multi-architecture image**  
+```
+make docker-buildx
+```
+
+2. Build and push the bundle image
+```
+make bundle bundle-build bundle-push
+```
+
+3. Build and push the catalog images
+```
+make catalog-build catalog-push
+````
+This will build and push the catalog image with the version tag `v0.0.1-alpha3` and `latest`.