Confluence on Docker runs setup assistent on existing installation after update - docker

Question

A few days ago, my watchtower updated Confluence on Docker with the 6.15.1-alpine tag. It's hosted using Atlassians official image. Since those update, Confluence shows the setup screen. Haven't any chance to get inside the admin panel. When continue the wizard end entering server credentials of the existing installation, it gave an error that an installation already exists that would be overwritten if continued.
It was a re-push of the exact version tag 6.15.1 tag, not a regular version update. So there seems no possibility to use the old, working image. Also other versions seems re-pushed. Tried some older ones and also a new one, without success.
docker-compose.yml
version: "2"
volumes:
confluence-home:
services:
confluence:
container_name: confluence
image: atlassian/confluence-server:6.15.1-alpine
#restart: always
mem_limit: 6g
volumes:
- confluence-home:/var/atlassian/application-data/confluence
- ./confluence.cfg.xml:/var/atlassian/application-data/confluence/confluence.cfg.xml
- ./server.xml:/opt/atlassian/confluence/conf/server.xml
- ./mysql-connector-java-5.1.42-bin.jar:/opt/atlassian/confluence/lib/mysql-connector-java-5.1.42-bin.jar
networks:
- traefik
environment:
- "TZ=Europe/Berlin"
- JVM_MINIMUM_MEMORY=4096m
- JVM_MAXIMUM_MEMORY=4096m
labels:
- "traefik.port=8090"
- "traefik.backend=confluence"
- "traefik.frontend.rule=Host:confluence.my-domain.com"
networks:
traefik:
external: true

Answer 1

I found out that there were the following changes on the images:
Ownership
The logs throwed errors about not beinng able to write on log files because nearly the entire home directory was owned by an user called bin:
root#8ac38faa94f1:/var/atlassian/application-data/confluence# ls -l
total 108
drwx------ 2 bin bin 4096 Aug 19 00:03 analytics-logs
drwx------ 3 bin bin 4096 Jun 15 2017 attachments
drwx------ 2 bin bin 24576 Jan 12 2019 backups
[...]
This could be fixed by executing a chown:
docker exec -it confluence bash
chown confluence:confluence -R /var/atlassian/application-data/confluence
Moutings inside mount
My docker-compose.yml mounts a volume to /var/atlassian/application-data/confluence and inside those volume, the confluence.cfg.xml file was mounted from current directory. This approach is a bit older and should seperate the user data in the volume from configuration files like docker-compose.yml and also the application itself as confluence.cfg.xml.
Seems not properly working any more on using Docker 17.05 and Docker-Compose 1.8.0 (at least in combination with Confluence), so I simply removed that second mount and placed the configuration file inside the volume.
Atlassian creates config files now dynamically
It was noticeable that my mounted configuration files like confluence.cfg.xml and server.xml were overwritten by Atlassians container. Their source code shows that they now use Jina2, a common Python template engine used in e.g. Ansible. A python script parse those files on startup and create Confluences configuration files, without properly checking on all of those files if they already exists.
Mounting them as read only caused the app to crash because this is also not handled in their Python script. By analyzing their templates, I learned that they replaced nearly every config item by environment variables. Not a bad approach, so I specified my server.xml parameters by env variables instead of mouting the entire file.
In my case, Confluence is behind a Traefik reverse proxy and it's required to tell Confluence it's final application url for end users:
environment:
- ATL_proxyName=confluence.my-domain.com
- ATL_proxyPort=443
- ATL_tomcat_scheme=https
Final working docker-compose.yml
By applying all modifications above, accessing the existing installation works again using the following docker-compose.yml file:
version: "2"
volumes:
confluence-home:
services:
confluence:
container_name: confluence
image: atlassian/confluence-server:6.15.1
#restart: always
mem_limit: 6g
volumes:
- confluence-home:/var/atlassian/application-data/confluence
- ./mysql-connector-java-5.1.42-bin.jar:/opt/atlassian/confluence/lib/mysql-connector-java-5.1.42-bin.jar
networks:
- traefik
environment:
- "TZ=Europe/Berlin"
- JVM_MINIMUM_MEMORY=4096m
- JVM_MAXIMUM_MEMORY=4096m
- ATL_proxyName=confluence.my-domain.com
- ATL_proxyPort=443
- ATL_tomcat_scheme=https
labels:
- "traefik.port=8090"
- "traefik.backend=confluence"
- "traefik.frontend.rule=Host:confluence.my-domain.com"
networks:
traefik:
external: true