For the posterity : Backing up Rocket.chat on SERVER 1 and Restore it on SERVER 2, based on the official docker image :
SERVER 1
cd /backups
docker run -it --rm --link db -v /backups:/backups mongo:3.0 mongodump -h db -o /backups/mongoBACKUP
tar czf mongoBACKUP.tar.gz mongoBACKUP/
Then send mongoBACKUP.tar.gz
on SERVER 2 in /backups
.
SERVER 2 (+ test on :3000)
docker run --name db -d mongo:3.0 --smallfiles
cd /backups
tar xzf mongoBACKUP.tar.gz
docker run -it --rm --name mongorestore -v /backups/mongoBACKUP:/var/dump --link db:db mongo mongorestore --host db /var/dump
docker run -p 3000:3000 --name rocket --env ROOT_URL=http://yourwebsite.test --expose 3000 --link db -d rocket.chat