For now I store my mails in a local directory. @tve Is it possible to mount a local directory to this persistent state directory too?

I would be very happy if this PR could be merged.

@Josef-Friedrich if by "local directory" you mean a directory on the docker host, then yes, you can do that. My docker-compose-fu isn't well developed yet, but for sure it works if you use something like the following in your docker-compose.yaml:

services:
  mail:
    ...
    volumes:
    - /mnt/mail-state:/var/mail-state

Here /mnt/mail-state is a directory on the host. You can then back this dir up. I haven't figured out how to do it with the named volumes syntax.

Docs for the wiki (waiting to hear from @tomav whether he likes the direction of this PR):

Configuring Backups

User mail directories

Assuming that you use docker-compose and a data volume container named maildata, you can backup your user mails like this:

docker run --rm \
--volumes-from maildata_1 \
-v "$(pwd)":/backups \
-ti tvial/docker-mailserver \
tar cvzf /backups/docker-mailserver-`date +%y%m%d-%H%M%S`.tgz /var/mail

Mail state directories

In addition to the user mail directories you may want to persist and even back up the state of the various daemons, such as postfix mail queues, clamav virus database, spamassassin learning, etc. Inside the container the files for this are normally found in various directories under /var/lib and /var/spool but by adding the ONE_DIR=1 option to the environment these all get moved to /var/mail-state at container start-up. This allows you to mount a volume there, which has the first benefit that all this state is persisted if you need to restart the container. As a second benefit, you can also back this volume up to secondary storage, although it is not really required, i.e., no email will get lost unless something was just in transit in the postfix queues.

In docker-compose.yaml you can enable the merging of all daemon state into one directory and the mounting of a volume as follows:

services:
  mail:
    ...
    environment:
      ...
    - ONE_DIR=1
    volumes:
    ...
    - mailstate:/var/mail-state

volumes:
  ...
  mailstate:
    driver: local

This configuration persists the mailstat volume across container restarts. If you want to back mailstate up to secondary storage you need to launch a backup container as suggested above for maildata backups. Alternatively, you can also mount one or both volumes from a specific path on the host. To do that do not use the named volumes syntax and instead use something like:

services:
  mail:
    ...
    environment:
      ...
    - ONE_DIR=1
    volumes:
    - /on/the/host/mail-data:/var/mail
    - /on/the/host/mail-state:/var/mail-state

This second form is useful if you want to place these volumes onto a filesystem/device where you perform snapshot backups or something similar.

I'm having trouble getting a build to complete. Travis times out just building the container images :-(

The download of the main.cvd is very slow. I'm just building the image on my laptop ...

Yeah, I did set things up so I could build and test locally, and there the tests pass. It's just not nice to have a PR where "all checks have failed"...

Just restarted the build.
https://travis-ci.org/tomav/docker-mailserver/builds/132603315

A question: why don't we change where these daemons write their content to the single folder, using configuration files, instead of adding new code in start-mailserver.sh.

That's certainly a very valid alternative. I didn't want to dive into the documentation for the 7 different daemons to find what I had to change and then test that I didn't forget something, etc...

I understand, but there's another easier way by adding the folder list to a data container.

version: '2'

services:
  mail:
    image: tvial/docker-mailserver:latest
    # build: .
    hostname: mail
    domainname: domain.com
    container_name: mail
    ports:
    - "25:25"
    - "143:143"
    - "587:587"
    - "993:993"
    volumes:
    - maildata:/var/mail
    - maildata:/var/spool/postfix
    - maildata:/var/lib/postfix
    - maildata:/var/lib/amavis
    - maildata:/var/lib/clamav
    - maildata:/var/lib/spamassasin
    - maildata:/var/lib/fail2ban
    - ./config/:/tmp/docker-mailserver/

volumes:
  maildata:
    driver: local

No code, and it's more docker compliant.

Interesting, I didn't know one could do that. I guess no PR needed in that case? I'll keep using my fork because I want to map these directories to an EC2 EBS volume so I can do snapshot-backups and I can't do that easily with docker volumes, but that may not be of interest to many other folks.

@tomav I tried your docker-compose.yml file from above. I got this error:

mail | May 29 19:45:31 mail postfix/master[642]: fatal: open lock file /var/lib/postfix/master.lock: cannot create file exclusively: Permission denied

There are some ownerships/permissions to set.
Let's gonna list them here.

- maildata:/var/spool/postfix
- maildata:/var/lib/postfix => postfix:postfix
- maildata:/var/lib/amavis => amavis:amavis with default directories (tmp and db)
- maildata:/var/lib/clamav => clamav:clamav
- maildata:/var/lib/spamassasin
- maildata:/var/lib/fail2ban

No time for this right time.

I'm gonna merge your PR and will try to do something more docker compliant later.

Thanks for the work anyway!