Doc: Apply changes to flux variables

docs/maintenance.rst

@@ -190,6 +190,19 @@ You can delete all evicted pods with this command:
 
    kubectl get pods --all-namespaces -ojson | jq -r '.items[] | select(.status.reason!=null) | select(.status.reason | contains("Evicted")) | .metadata.name + " " + .metadata.namespace' | xargs -n2 -l bash -c 'kubectl delete pods $0 --namespace=$1'
 
+Apply changes to flux variables
+-------------------------------
+
+Before installing, you configured cluster variables in your cluster directory
+in `.flux.env`. If you change any of these variables after installation you can
+apply the changes by following the *Step 1*: `Install core applications`_
+instructions until the step ``kubectl apply -k $CLUSTER_DIR``. Then, use the
+following command that will apply the changes to all installed helm releases:
+
+.. code:: bash
+
+    kubectl get -A hr --template '{{range .items}}{{.metadata.namespace}}/{{.metadata.name}}{{"\n"}}{{end}}' | awk -F'/' '{system("flux reconcile -n " $1 " helmrelease " $2)}'
+
 
 .. _kubectl logs: https://kubernetes.io/docs/concepts/cluster-administration/logging
 .. _Promtail: https://grafana.com/docs/loki/latest/clients/promtail/
@@ -203,3 +216,4 @@ You can delete all evicted pods with this command:
 .. _reach out to us: https://openappstack.net/contact.html
 .. _taints: https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/
 .. _out of resource handling with kubelet: https://kubernetes.io/docs/tasks/administer-cluster/out-of-resource/
+.. _Install core applications: https://docs.openappstack.net/en/v0.7/installation/install_oas.html#step-1-install-core-applications