Remove mysql_user and update documentation (#1139)

* Remove mysql_user and update documentation

* MG, udpate based on maintainers feedback

* Remove extra comments for password, already in doc

docs/content/gettingstarted.md

@@ -5,7 +5,7 @@ weight: 20
 
 ## On Sandbox
 
-We offer a sandbox installation that is free for everyone to try out hawkBit's [Management UI](/hawkbit/ui/), 
+We offer a sandbox installation that is free for everyone to try out hawkBit's [Management UI](/hawkbit/ui/),
 [Management API](/hawkbit/apis/management_api/), and [Direct Device Integration API](/hawkbit/apis/ddi_api/):  
 **[<i class="fas fa-desktop">&nbsp;</i> https://hawkbit.eclipse.org](https://hawkbit.eclipse.org)**
 
@@ -26,10 +26,12 @@ In addition, the following vendors offer free trial accounts for their Eclipse h
 
 | Service / Container | A | B | C |
 |---|---|---|---|
-| hawkBit Update Server |  &#10003; | &#10003; | &#10003; | 
-| hawkBit Device Simulator |   |  | &#10003; | 
-| MySQL |  | &#10003; | &#10003; | 
-| RabbitMQ |  | &#10003; | &#10003; | 
+| hawkBit Update Server |  &#10003; | &#10003; | &#10003; |
+| hawkBit Device Simulator |   |  | &#10003; |
+| MySQL |  | &#10003; | &#10003; |
+| RabbitMQ |  | &#10003; | &#10003; |
+
+HawkBit Update Server uses username=admin and password=admin as default login credentials. They can be overridden by the environment variables spring.security.user.name and spring.security.user.password which are defined in the corresponding default [application.properties](hawkbit-runtime/hawkbit-update-server/src/main/resources/application.properties).
 
 ### A: Run hawkBit Update Server as Docker Container
 

hawkbit-runtime/docker/docker-compose-stack.yml

@@ -79,7 +79,7 @@ services:
         condition: on-failure
     environment:
       MYSQL_DATABASE: "hawkbit"
-      MYSQL_USER: "root"
+      # MYSQL_USER: "root" is created by default in the container for mysql 5.7+
       MYSQL_ALLOW_EMPTY_PASSWORD: "true"
 
 

hawkbit-runtime/docker/docker-compose.yml

@@ -31,7 +31,7 @@ services:
     image: "mysql:5.7"
     environment:
       MYSQL_DATABASE: "hawkbit"
-      MYSQL_USER: "root"
+      # MYSQL_USER: "root" is created by default in the container for mysql 5.7+
       MYSQL_ALLOW_EMPTY_PASSWORD: "true"
     restart: always
     ports: