set the right timezone inside containers

docker-compose.yml

@@ -9,8 +9,11 @@ services:
     restart: unless-stopped
     volumes:
       - ${POSTGRES_DATA_PATH}:/var/lib/postgresql/data
-      - /etc/localtime:/etc/localtime:ro
     environment:
+      # timezone inside container
+      - TZ
+
+      # necessay Postgres options/variables
       - POSTGRES_USER
       - POSTGRES_PASSWORD
       - POSTGRES_DB
@@ -24,7 +27,9 @@ services:
       - ${NGINX_DHPARAMS_FILE}:/dhparams4096.pem
       - ${CERT_PATH}:/cert.pem:ro
       - ${KEY_PATH}:/key.pem:ro
-      - /etc/localtime:/etc/localtime:ro
+    environment:
+      # timezone inside container
+      - TZ
     ports:
       - ${HTTPS_PORT}:443
       - ${HTTP_PORT}:80
@@ -42,9 +47,11 @@ services:
       - ${MATTERMOST_LOGS_PATH}:/mattermost/logs:rw
       - ${MATTERMOST_PLUGINS_PATH}:/mattermost/plugins:rw
       - ${MATTERMOST_CLIENT_PLUGINS_PATH}:/mattermost/client-plugins:rw
-      - /etc/localtime:/etc/localtime:ro
     environment:
-      # necessary options/variables (see env.example)
+      # timezone inside container
+      - TZ
+
+      # necessary Mattermost options/variables (see env.example)
       - MM_SQLSETTINGS_DRIVERNAME
       - MM_SQLSETTINGS_DATASOURCE
 

env.example

@@ -1,3 +1,9 @@
+# Container settings
+## Timezone inside the containers. The value needs to be in the form 'Europe/Berlin'.
+## A list of these tz database names can be looked up at Wikipedia
+## https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
+TZ=UTC
+
 # Postrges settings
 ## Documentation for this image and available settings can be found on hub.docker.com
 ## https://hub.docker.com/_/postgres