health add alarm docker container down (netdata#18075)

src/health/health.d/docker.conf

@@ -1,4 +1,6 @@
- template: docker_container_unhealthy
+# you can disable an alarm notification by setting the 'to' line to: silent
+
+template: docker_container_unhealthy
        on: docker.container_health_status
     class: Errors
      type: Containers
@@ -10,3 +12,22 @@ component: Docker
   summary: Docker container ${label:container_name} health
      info: ${label:container_name} docker container health status is unhealthy
        to: sysadmin
+
+# This alert monitors the status of Docker containers and triggers if any container is exited (down).
+# To enable this alert for specific containers, you need to modify the "chart labels" filter.
+# This filter uses Netdata's simple pattern matching syntax.
+
+    template: docker_container_down
+          on: docker.container_state
+       class: Errors
+        type: Containers
+   component: Docker
+chart labels: container_name=!*
+       units: status
+       every: 10s
+      lookup: average -10s of exited
+        warn: $this > 0
+       delay: down 1m multiplier 1.5 max 2h
+     summary: Docker container ${label:container_name} down
+        info: Docker container ${label:container_name} is currently not running
+          to: sysadmin