Use restart policy unless-stopped (#811)

Ensures Docker automatically restarts services (containers) that were running on the host prior to a reboot.

docker-compose.yml

@@ -57,6 +57,7 @@ services:
       discovery.type: single-node
     networks:
       - elk
+    restart: unless-stopped
 
   logstash:
     build:
@@ -78,6 +79,7 @@ services:
       - elk
     depends_on:
       - elasticsearch
+    restart: unless-stopped
 
   kibana:
     build:
@@ -94,6 +96,7 @@ services:
       - elk
     depends_on:
       - elasticsearch
+    restart: unless-stopped
 
 networks:
   elk: