REDMINE_SECRET_KEY_BASE is required for Docker Swarm (#1659)

redmine/content.md

@@ -118,7 +118,7 @@ This variable allows you to control if `rake redmine:plugins:migrate` is run on
 
 ### `REDMINE_SECRET_KEY_BASE`
 
-This variable is used to create an initial `config/secrets.yml` and set the `secret_key_base` value, which is "used by Rails to encode cookies storing session data thus preventing their tampering. Generating a new secret token invalidates all existing sessions after restart" ([session store](https://www.redmine.org/projects/redmine/wiki/RedmineInstall#Step-5-Session-store-secret-generation)). If you do not set this variable or provide a `secrets.yml` one will be generated using `rake generate_secret_token`.
+This variable is required when using Docker Swarm replicas to maintain session connections when being loadbalanced between containers. It will create an initial `config/secrets.yml` and set the `secret_key_base` value, which is "used by Rails to encode cookies storing session data thus preventing their tampering. Generating a new secret token invalidates all existing sessions after restart" ([session store](https://www.redmine.org/projects/redmine/wiki/RedmineInstall#Step-5-Session-store-secret-generation)). If you do not set this variable or provide a `secrets.yml` one will be generated using `rake generate_secret_token`.
 
 ## Docker Secrets
 

redmine/stack.yml

@@ -10,6 +10,7 @@ services:
     environment:
       REDMINE_DB_MYSQL: db
       REDMINE_DB_PASSWORD: example
+      REDMINE_SECRET_KEY_BASE: supersecretkey
 
   db:
     image: mysql:5.7