docs: document installation of EDB Postgres for Kubernetes from priva…

…te registries (#120)

Signed-off-by: Niccolò Fei <[email protected]>
Signed-off-by: Gabriele Bartolini <[email protected]>
Co-authored-by: Jaime Silvela <[email protected]>
Co-authored-by: Gabriele Bartolini <[email protected]>

README.md

@@ -42,6 +42,40 @@ edb-pg4k-edb-postgres-for-kubernetes   1/1     1            1           11s
 Once it is ready, you can verify that you can deploy the sample cluster
 suggested by the helm chart.
 
+### Deploying EDB Postgres for Kubernetes (PG4K) operator from EDB's private registry
+
+By default, PG4K will be deployed using [images publicly hosted on Quay.io](https://quay.io/repository/enterprisedb/cloud-native-postgresql),
+without a `pullSecret` but requiring a [license key](https://www.enterprisedb.com/docs/postgres_for_kubernetes/latest/license_keys/).
+
+Additionally, both the operator and the operand images required by PG4K may be
+pulled from the `k8s_enterprise` or `k8s_standard` repositories at
+`docker.enterprisedb.com`, available with an EDB subscription plan.
+
+To do that, you need to configure the chart to pull images from a private
+registry (this works similarly in case you want to host the operator images in
+your own private registry).
+
+For example, to deploy via the `k8s_enterprise` repository:
+
+```console
+helm upgrade --install edb-pg4k \
+  --namespace postgresql-operator-system \
+  --create-namespace \
+  --set image.repository=docker.enterprisedb.com/k8s_enterprise/edb-postgres-for-kubernetes \
+  --set image.imageCredentials.username=k8s_enterprise \
+  --set image.imageCredentials.password=<THE-TOKEN> \
+  --set image.imageCredentials.create=true \
+  --set imagePullSecrets[0].name=postgresql-operator-pull-secret \
+  --set config.data.PULL_SECRET_NAME=postgresql-operator-pull-secret \
+  edb/edb-postgres-for-kubernetes
+```
+
+> **Note:** If instead you want to deploy using the `k8s_standard` repository,
+> you can do that by adjusting the following settings in the above example:
+>
+> - Set `image.repository` to `docker.enterprisedb.com/k8s_standard/edb-postgres-for-kubernetes`
+> - Set `image.imageCredentials.username` to `k8s_standard`
+
 ## Deployment of the EDB Postgres Distributed for Kubernetes operator (PG4K-PGD)
 
 **Note:** the `edb-postgres-distributed-for-kubernetes` chart will by default