Small and flexible docker image with vsftpd server

docker run -d \
    -p "21:21" \
    -p 21000-21010:21000-21010 \
    -e USERS="one|1234" \
    -e ADDRESS=ftp.site.domain \
    delfer/alpine-ftp-server

Environment variables:

• USERS - space and | separated list (optional, default: alpineftp|alpineftp)
  • format name1|password1|[folder1][|uid1][|gid1] name2|password2|[folder2][|uid2][|gid2]
• ADDRESS - external address to which clients can connect for passive ports (optional, should resolve to ftp server ip address)
• MIN_PORT - minimum port number to be used for passive connections (optional, default 21000)
• MAX_PORT - maximum port number to be used for passive connections (optional, default 21010)

• user|password foo|bar|/home/foo
• user|password|/home/user/dir|10000
• user|password|/home/user/dir|10000|10000
• user|password||10000
• user|password||10000|82 : add to an existing group (www-data)

Issue free Let's Encrypt certificate and use it with alpine-ftp-server.

mkdir -p /etc/letsencrypt
docker run -it --rm \
    -p 80:80 \
    -v "/etc/letsencrypt:/etc/letsencrypt" \
    certbot/certbot certonly \
    --standalone \
    --preferred-challenges http \
    -n --agree-tos \
    --email [email protected] \
    -d ftp.site.domain
docker run -d \
    --name ftp \
    -p "21:21" \
    -p 21000-21010:21000-21010 \
    -v "/etc/letsencrypt:/etc/letsencrypt:ro" \
    -e USERS="one|1234" \
    -e ADDRESS=ftp.site.domain \
    -e TLS_CERT="/etc/letsencrypt/live/ftp.site.domain/fullchain.pem" \
    -e TLS_KEY="/etc/letsencrypt/live/ftp.site.domain/privkey.pem" \
    delfer/alpine-ftp-server

• Do not forget to replace ftp.site.domain with actual domain pointing to your server's IP.
• Be sure you have avalible port 80 for standalone mode of certbot to issue certificate.
• Do not forget to renew certificate in 3 month with certbot renew command.

alpine-ftp-server:
  image: delfer/alpine-ftp-server
  ports:
    - "21:21"
    - 21000-21010:21000-21010
  environment:
    - USERS="one|1234"
    - ADDRESS=ftp.site.domain
  volumes:
    - ...

• If translating the docker run commands to docker-compose files (which uses YAML format), note that YAML parses numbers in the format xx:yy as a base-60 value if the number is less than 60, so 21:21 must be specified as a quoted string