docs: add initial reference for "stack services"

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/reference/commandline/stack_config.md

@@ -27,4 +27,5 @@ Displays the configuration of a stack.
 
 * [stack deploy](stack_deploy.md)
 * [stack rm](stack_rm.md)
+* [stack services](stack_services.md)
 * [stack tasks](stack_tasks.md)

docs/reference/commandline/stack_deploy.md

@@ -56,4 +56,5 @@ axqh55ipl40h  vossibility-stack_vossibility-collector  1 icecrime/vossibility-co
 
 * [stack config](stack_config.md)
 * [stack rm](stack_rm.md)
+* [stack services](stack_services.md)
 * [stack tasks](stack_tasks.md)

docs/reference/commandline/stack_rm.md

@@ -30,4 +30,5 @@ a manager node.
 
 * [stack config](stack_config.md)
 * [stack deploy](stack_deploy.md)
+* [stack services](stack_services.md)
 * [stack tasks](stack_tasks.md)

docs/reference/commandline/stack_services.md

@@ -0,0 +1,65 @@
+<!--[metadata]>
++++
+title = "stack services"
+description = "The stack services command description and usage"
+keywords = ["stack, services"]
+advisory = "experimental"
+[menu.main]
+parent = "smn_cli"
++++
+<![end-metadata]-->
+
+# stack services (experimental)
+
+```markdown
+Usage:	docker stack services [OPTIONS] STACK
+
+List the services in the stack
+
+Options:
+  -f, --filter value   Filter output based on conditions provided
+      --help           Print usage
+  -q, --quiet          Only display IDs
+```
+
+Lists the services that are running as part of the specified stack. This
+command has to be run targeting a manager node.
+
+For example, the following command shows all services in the `myapp` stack:
+
+```bash
+$ docker stack services myapp
+
+ID            NAME            REPLICAS  IMAGE                                                                          COMMAND
+7be5ei6sqeye  myapp_web       1/1       nginx@sha256:23f809e7fd5952e7d5be065b4d3643fbbceccd349d537b62a123ef2201bc886f
+dn7m7nhhfb9y  myapp_db        1/1       mysql@sha256:a9a5b559f8821fe73d58c3606c812d1c044868d42c63817fa5125fd9d8b7b539
+```
+
+## Filtering
+
+The filtering flag (`-f` or `--filter`) format is a `key=value` pair. If there
+is more than one filter, then pass multiple flags (e.g. `--filter "foo=bar" --filter "bif=baz"`).
+Multiple filter flags are combined as an `OR` filter. 
+
+The following command shows both the `web` and `db` services:
+
+```bash
+$ docker stack services --filter name=myapp_web --filter name=myapp_db myapp
+
+ID            NAME            REPLICAS  IMAGE                                                                          COMMAND
+7be5ei6sqeye  myapp_web       1/1       nginx@sha256:23f809e7fd5952e7d5be065b4d3643fbbceccd349d537b62a123ef2201bc886f
+dn7m7nhhfb9y  myapp_db        1/1       mysql@sha256:a9a5b559f8821fe73d58c3606c812d1c044868d42c63817fa5125fd9d8b7b539
+```
+
+The currently supported filters are:
+
+* id / ID (`--filter id=7be5ei6sqeye`, or `--filter ID=7be5ei6sqeye`)
+* name (`--filter name=myapp_web`)
+* label (`--filter label=key=value`)
+
+## Related information
+
+* [stack config](stack_config.md)
+* [stack deploy](stack_deploy.md)
+* [stack rm](stack_rm.md)
+* [stack tasks](stack_tasks.md)

docs/reference/commandline/stack_tasks.md

@@ -44,3 +44,4 @@ The currently supported filters are:
 * [stack config](stack_config.md)
 * [stack deploy](stack_deploy.md)
 * [stack rm](stack_rm.md)
+* [stack services](stack_services.md)