Merge pull request #13574 from adellape/idling_4.0

Add idling topics to 4.0

Author: adellape

_topic_map.yml

@@ -173,6 +173,8 @@ Topics:
   File: quotas-setting-per-project
 - Name: Setting resource quotas across multiple projects
   File: quotas-setting-across-multiple-projects
+- Name: Idling applications
+  File: idling-applications
 - Name: Extending the Kubernetes API with CRDs
   File: crd-extending-api-with-crds
 ---

masters/idling-applications.adoc

@@ -0,0 +1,23 @@
+[id='idling_applications']
+= Idling applications
+include::modules/common-attributes.adoc[]
+:context: idling-applications
+
+toc::[]
+
+{nbsp} +
+Cluster administrators can idle applications to reduce resource consumption.
+This is useful when the cluster is deployed on a public cloud where cost is
+related to resource consumption.
+
+If any scalable resources are not in use, {product-title} discovers and idles
+them by scaling their replicas to `0`. The next time network traffic is directed
+to the resources, the resources are unidled by scaling up the replicas, and
+normal operation continues.
+
+Applications are made of services, as well as other scalable resources, such as
+deployment configurations. The action of idling an application involves idling
+all associated resources.
+
+include::modules/idle-idling-applications.adoc[leveloffset=+1]
+include::modules/idle-unidling-applications.adoc[leveloffset=+1]

modules/idle-idling-applications.adoc

@@ -0,0 +1,48 @@
+// Module included in the following assemblies:
+//
+// * masters/idling-applications.adoc
+
+[id='idle-idling-applications-{context}']
+= Idling applications
+
+Idling an application involves finding the scalable resources (deployment
+configurations, replication controllers, and others) associated with a service.
+Idling an application finds the service and marks it as idled, scaling down the
+resources to zero replicas.
+
+You can use the `oc idle` command to idle a single service, or use the
+`--resource-names-file` option to idle multiple services.
+
+[id='idle-idling-applications-single-{context}']
+== Idling a single service
+
+.Procedure
+
+. To idle a single service, run:
++
+----
+$ oc idle <service>
+----
+
+[id='idle-idling-applications-multiple-{context}']
+== Idling multiple services
+
+Idling multiple services is helpful if an application spans across a set of
+services within a project, or when idling multiple services in conjunction with
+a script in order to idle multiple applications in bulk within the same project.
+
+.Procedure
+
+. Create a file containing a list of the services, each on their own line.
+
+. Idle the services using the `--resource-names-file` option:
++
+----
+$ oc idle --resource-names-file <filename>
+----
+
+[NOTE]
+====
+The `idle` command is limited to a single project. For idling applications across
+a cluster, run the `idle` command for each project individually.
+====

modules/idle-unidling-applications.adoc

@@ -0,0 +1,26 @@
+// Module included in the following assemblies:
+//
+// * masters/idling-applications.adoc
+
+[id='idle-unidling-applications-{context}']
+= Unidling applications
+
+Application services become active again when they receive network traffic and
+are scaled back up their previous state. This includes both traffic to the
+services and traffic passing through routes.
+
+Applications can also be manually unidled by scaling up the resources.
+
+.Procedure
+
+. To scale up a Deployment Configuration, run:
++
+----
+$ oc scale --replicas=1 dc <dc_name>
+----
+
+[NOTE]
+====
+Automatic unidling by a router is currently only supported by the default
+HAProxy router.
+====