chore: Add upgrade instructions to release template

Author: Techassi

modules/ROOT/partials/release-notes/release-template.adoc

@@ -65,6 +65,127 @@ Of the changes mentioned above, the following are breaking (or could lead to bre
 
 ===== Using stackablectl
 
+Uninstall the `OO.M` release
+
+[source,console]
+----
+$ stackablectl release uninstall OO.M
+
+Uninstalled release 'OO.M'
+
+Use "stackablectl release list" to list available releases.
+# ...
+----
+
+Afterwards you will need to upgrade the CustomResourceDefinitions (CRDs) installed by the Stackable Platform.
+The reason for this is that helm will uninstall the operators but not the CRDs.
+This can be done using `kubectl replace`.
+
+[source]
+----
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/airflow-operator/OO.M.X/deploy/helm/airflow-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/commons-operator/OO.M.X/deploy/helm/commons-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/druid-operator/OO.M.X/deploy/helm/druid-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hbase-operator/OO.M.X/deploy/helm/hbase-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hdfs-operator/OO.M.X/deploy/helm/hdfs-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hive-operator/OO.M.X/deploy/helm/hive-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/kafka-operator/OO.M.X/deploy/helm/kafka-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/listener-operator/OO.M.X/deploy/helm/listener-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/nifi-operator/OO.M.X/deploy/helm/nifi-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/opa-operator/OO.M.X/deploy/helm/opa-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/secret-operator/OO.M.X/deploy/helm/secret-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/spark-k8s-operator/OO.M.X/deploy/helm/spark-k8s-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/superset-operator/OO.M.X/deploy/helm/superset-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/trino-operator/OO.M.X/deploy/helm/trino-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/zookeeper-operator/OO.M.X/deploy/helm/zookeeper-operator/crds/crds.yaml
+----
+
+[source,console]
+----
+customresourcedefinition.apiextensions.k8s.io "airflowclusters.airflow.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "airflowdbs.airflow.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "authenticationclasses.authentication.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "s3connections.s3.stackable.tech" replaced
+...
+----
+
+Install the `YY.M` release
+
+[source,console]
+----
+$ stackablectl release install YY.M
+
+Installed release 'YY.M'
+
+Use "stackablectl operator installed" to list installed operators.
+----
+
 ===== Using Helm
 
+Use `helm list` to list the currently installed operators.
+
+You can use the following command to uninstall all operators that are part of the `OO.M` release:
+
+[source,console]
+----
+$ helm uninstall airflow-operator commons-operator druid-operator hbase-operator hdfs-operator hive-operator kafka-operator listener-operator nifi-operator opa-operator secret-operator spark-k8s-operator superset-operator trino-operator zookeeper-operator
+release "airflow-operator" uninstalled
+release "commons-operator" uninstalled
+...
+----
+
+Afterward you will need to upgrade the CustomResourceDefinitions (CRDs) installed by the Stackable Platform.
+The reason for this is that helm will uninstall the operators but not the CRDs. This can be done using `kubectl replace`:
+
+[source]
+----
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/airflow-operator/OO.M.X/deploy/helm/airflow-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/commons-operator/OO.M.X/deploy/helm/commons-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/druid-operator/OO.M.X/deploy/helm/druid-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hbase-operator/OO.M.X/deploy/helm/hbase-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hdfs-operator/OO.M.X/deploy/helm/hdfs-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/hive-operator/OO.M.X/deploy/helm/hive-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/kafka-operator/OO.M.X/deploy/helm/kafka-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/listener-operator/OO.M.X/deploy/helm/listener-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/nifi-operator/OO.M.X/deploy/helm/nifi-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/opa-operator/OO.M.X/deploy/helm/opa-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/secret-operator/OO.M.X/deploy/helm/secret-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/spark-k8s-operator/OO.M.X/deploy/helm/spark-k8s-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/superset-operator/OO.M.X/deploy/helm/superset-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/trino-operator/OO.M.X/deploy/helm/trino-operator/crds/crds.yaml
+kubectl replace -f https://raw.githubusercontent.com/stackabletech/zookeeper-operator/OO.M.X/deploy/helm/zookeeper-operator/crds/crds.yaml
+----
+
+[source,console]
+----
+customresourcedefinition.apiextensions.k8s.io "airflowclusters.airflow.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "airflowdbs.airflow.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "authenticationclasses.authentication.stackable.tech" replaced
+customresourcedefinition.apiextensions.k8s.io "s3connections.s3.stackable.tech" replaced
+...
+----
+
+Install the `YY.M` release
+
+[source,console]
+----
+helm repo add stackable-stable https://repo.stackable.tech/repository/helm-stable/
+helm repo update stackable-stable
+helm install --wait airflow-operator stackable-stable/airflow-operator --version OO.M.X
+helm install --wait commons-operator stackable-stable/commons-operator --version OO.M.X
+helm install --wait druid-operator stackable-stable/druid-operator --version OO.M.X
+helm install --wait hbase-operator stackable-stable/hbase-operator --version OO.M.X
+helm install --wait hdfs-operator stackable-stable/hdfs-operator --version OO.M.X
+helm install --wait hive-operator stackable-stable/hive-operator --version OO.M.X
+helm install --wait kafka-operator stackable-stable/kafka-operator --version OO.M.X
+helm install --wait listener-operator stackable-stable/listener-operator --version OO.M.X
+helm install --wait nifi-operator stackable-stable/nifi-operator --version OO.M.X
+helm install --wait opa-operator stackable-stable/opa-operator --version OO.M.X
+helm install --wait secret-operator stackable-stable/secret-operator --version OO.M.X
+helm install --wait spark-k8s-operator stackable-stable/spark-k8s-operator --version OO.M.X
+helm install --wait superset-operator stackable-stable/superset-operator --version OO.M.X
+helm install --wait trino-operator stackable-stable/trino-operator --version OO.M.X
+helm install --wait zookeeper-operator stackable-stable/zookeeper-operator --version OO.M.X
+----
+
 ==== Known issues