Merge pull request openshift#2150 from kargakis/deployment-triggers-doc

Information about deployment triggers

Author: tnguyen-rh

dev_guide/deployments.adoc

@@ -218,18 +218,18 @@ failed and has not been manually deleted or pruned).
 == Triggers
 
 A deployment configuration can contain triggers, which drive the creation of
-new deployments in response to events, both inside and outside OpenShift.
+new deployments in response to events, only inside OpenShift at the moment.
 
 WARNING: If no triggers are defined on a deployment configuration, deployments
 must be link:#start-deployment[started manually].
 
 [[config-change-trigger]]
 === Configuration Change Trigger
 
-The ConfigChange trigger results in a new deployment whenever changes are
-detected to the replication controller template of the deployment configuration.
+The ConfigChange trigger results in a new deployment whenever new changes are
+detected in the pod template of the deployment configuration.
 
-NOTE: If a ConfigChange trigger is defined on a deployment configuration,
+NOTE: If only a ConfigChange trigger is defined on a deployment configuration,
 the first deployment will be automatically created soon after the deployment
 configuration itself is created.
 
@@ -248,7 +248,7 @@ triggers:
 === Image Change Trigger
 
 The ImageChange trigger results in a new deployment whenever the value of an
-image stream tag changes.
+image stream tag changes either by a build or because it was imported.
 
 The following is an example of an ImageChange trigger:
 
@@ -270,9 +270,15 @@ triggers:
 ====
 
 With the above example, when the `latest` tag value of the `origin-ruby-sample`
-image stream changes and the new tag value differs from the current image
+image stream changes and the new image value differs from the current image
 specified in the deployment configuration's `helloworld` container, a new
-deployment is created using the new tag value for the `helloworld` container.
+deployment is created using the new image for the `helloworld` container.
+
+NOTE: If an ImageChange trigger is defined on a deployment configuration (with
+a ConfigChange trigger or with automatic=true) and the ImageStreamTag pointed
+by the ImageChange trigger does not exist yet then the first deployment will
+automatically start as soon as an image is imported or pushed by a build to the
+ImageStreamTag.
 
 [[strategies]]
 == Strategies