Clarify how retry works for tasks and services (#2600)

Author: r4victor

docs/docs/concepts/services.md

@@ -518,12 +518,30 @@ via the [`spot_policy`](../reference/dstack.yml/service.md#spot_policy) property
 
 ### Retry policy
 
-By default, if `dstack` can't find capacity, the task exits with an error, or the instance is interrupted, 
-the run will fail.
+By default, if `dstack` can't find capacity, or the service exits with an error, or the instance is interrupted, the run will fail.
 
 If you'd like `dstack` to automatically retry, configure the 
 [retry](../reference/dstack.yml/service.md#retry) property accordingly:
 
+<div editor-title="service.dstack.yml">
+
+```yaml
+type: service
+image: my-app:latest
+port: 80
+
+retry:
+  # Retry on specific events
+  on_events: [no-capacity, error, interruption]
+  # Retry for up to 1 hour
+  duration: 1h
+```
+
+</div>
+
+If one replica of a multi-replica service fails with retry enabled,
+`dstack` will resubmit only the failed replica while keeping active replicas running.
+
 --8<-- "docs/concepts/snippets/manage-fleets.ext"
 
 --8<-- "docs/concepts/snippets/manage-runs.ext"

docs/docs/concepts/tasks.md

@@ -387,7 +387,7 @@ via the [`spot_policy`](../reference/dstack.yml/task.md#spot_policy) property. I
 
 ### Retry policy
 
-By default, if `dstack` can't find capacity, the task exits with an error, or the instance is interrupted, 
+By default, if `dstack` can't find capacity, or the task exits with an error, or the instance is interrupted, 
 the run will fail.
 
 If you'd like `dstack` to automatically retry, configure the 
@@ -416,6 +416,9 @@ retry:
 
 </div>
 
+If one job of a multi-node task fails with retry enabled,
+`dstack` will stop all the jobs and resubmit the run.
+
 --8<-- "docs/concepts/snippets/manage-fleets.ext"
 
 --8<-- "docs/concepts/snippets/manage-runs.ext"