Document .Node.Hostname templating
Update placeholders table and add example code
Follow up to moby/moby#34686
@@ -833,6 +833,10 @@ Valid placeholders for the Go template are listed below:
<td><tt>.Node.ID</tt></td>
<td>Node ID</td>
</tr>
+ <tr>
+ <td><tt>.Node.Hostname</tt></td>
+ <td>Node Hostname</td>
+ </tr>
<tr>
<td><tt>.Task.ID</tt></td>
<td>Task ID</td>
@@ -851,11 +855,11 @@ Valid placeholders for the Go template are listed below:
#### Template example
In this example, we are going to set the template of the created containers based on the
-service's name and the node's ID where it sits.
+service's name, the node's ID and hostname where it sits.
```bash
$ docker service create --name hosttempl \
- --hostname="{{.Node.ID}}-{{.Service.Name}}"\
+ --hostname="{{.Node.Hostname}}-{{.Node.ID}}-{{.Service.Name}}"\
busybox top
va8ew30grofhjoychbr6iot8c
@@ -865,7 +869,7 @@ $ docker service ps va8ew30grofhjoychbr6iot8c
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
wo41w8hg8qan hosttempl.1 busybox:latest@sha256:29f5d56d12684887bdfa50dcd29fc31eea4aaf4ad3bec43daf19026a7ce69912 2e7a8a9c4da2 Running Running about a minute ago
-$ docker inspect --format="{{.Config.Hostname}}" hosttempl.1.wo41w8hg8qanxwjwsg4kxpprj
+$ docker inspect --format="{{.Config.Hostname}}" 2e7a8a9c4da2-wo41w8hg8qanxwjwsg4kxpprj-hosttempl
x3ti0erg11rjpg64m75kej2mz-hosttempl
```
