diff --git a/engine/swarm/services.md b/engine/swarm/services.md
index a7a90fc98ad..2f561ec7095 100644
--- a/engine/swarm/services.md
+++ b/engine/swarm/services.md
@@ -289,7 +289,18 @@ $ docker service create \
 Service constraints let you set criteria for a node to meet before the scheduler
 deploys a service to the node. You can apply constraints to the
 service based upon node attributes and metadata or engine metadata. For more
-information on constraints, refer to the `docker service create` [CLI reference](/engine/reference/commandline/service_create.md).
+information on constraints, refer to the `docker service create`
+[CLI reference](/engine/reference/commandline/service_create.md).
+
+Use placement preferences to divide tasks evenly over different categories of
+nodes. An example of where this may be useful is balancing tasks between
+multiple datacenters or availability zones. In this case, you can use a
+placement preference to spread out tasks to multiple datacenters and make the
+service more resilient in the face of a localized outage. You can use
+additional placement preferences to further divide tasks over groups of nodes.
+For example, you can balance them over multiple racks within each datacenter.
+For more information on constraints, refer to the `docker service create`
+[CLI reference](/engine/reference/commandline/service_create.md).
 
 ### Reserving memory or number of CPUs for a service
 
@@ -553,15 +564,14 @@ $ docker service create \
   --name myservice \
   <IMAGE>
 ```
- 
+
 > **Important:** If your volume driver accepts a comma-separated list as an option,
 > you must escape the value from the outer CSV parser. To escape a `volume-opt`,
 > surround it with double quotes (`"`) and surround the entire mount parameter
 > with single quotes (`'`).
-> 
+>
 > For example, the `local` driver accepts mount options as a comma-separated
 > list in the `o` parameter. This example shows the correctly to escape the list.
-> 
 >     $ docker service create \
 >          --mount 'type=volume,src=<VOLUME-NAME>,dst=<CONTAINER-PATH>,volume-driver=local,volume-opt=type=nfs,volume-opt=device=<nfs-server>:<nfs-path>,"volume-opt=o=addr=<nfs-address>,vers=4,soft,timeo=180,bg,tcp,rw"'
 >         --name myservice \