Easy to use SCP/SFTP/RSYNC server with OpenSSH using rssh to limit user to these services.

Easy to use SFTP (SSH File Transfer Protocol) server with OpenSSH. This is an automated build linked with the debian and alpine repositories.

• Required: define users as command arguments, STDIN or mounted in /etc/sftp-users.conf (syntax: user:pass[:e][:uid[:gid[:dir1[,dir2]...]]]...).
  • Set UID/GID manually for your users if you want them to make changes to your mounted volumes with permissions matching your host filesystem.
• Mount volumes in user's home folder.
  • You must mount volumes in separate directories inside the user's home directory (/home/user/mounted-directory).

docker run -p 22:22 -d atmoz/sftp foo:pass:::upload

User "foo" with password "pass" can login with sftp and upload files to a folder called "upload". No mounted directories or custom UID/GID. Later you can inspect the files and use --volumes-from to mount them somewhere else (or see next example).

Let's mount a directory and set UID (we will also provide our own hostkeys):

docker run \
    -v /host/upload:/home/foo/upload \
    -v /host/ssh_host_rsa_key:/etc/ssh/ssh_host_rsa_key \
    -v /host/ssh_host_rsa_key.pub:/etc/ssh/ssh_host_rsa_key.pub \
    -p 2222:22 -d atmoz/sftp \
    foo:pass:1001

sftp:
    image: atmoz/sftp
    volumes:
        - /host/upload:/home/foo/upload
        - /host/ssh_host_rsa_key:/etc/ssh/ssh_host_rsa_key
        - /host/ssh_host_rsa_key.pub:/etc/ssh/ssh_host_rsa_key.pub
    ports:
        - "2222:22"
    command: foo:pass:1001

The OpenSSH server runs by default on port 22, and in this example, we are forwarding the container's port 22 to the host's port 2222. To log in with the OpenSSH client, run: sftp -P 2222 foo@<host-ip>

docker run \
    -v /host/users.conf:/etc/sftp-users.conf:ro \
    -v mySftpVolume:/home \
    -v /host/ssh_host_rsa_key:/etc/ssh/ssh_host_rsa_key \
    -v /host/ssh_host_rsa_key.pub:/etc/ssh/ssh_host_rsa_key.pub \
    -p 2222:22 -d atmoz/sftp

/host/users.conf:

foo:123:1001:100
bar:abc:1002:100
baz:xyz:1003:100

Add :e behind password to mark it as encrypted. Use single quotes if using terminal.

docker run \
    -v /host/share:/home/foo/share \
    -p 2222:22 -d atmoz/sftp \
    'foo:$1$0G2g0GSt$ewU0t6GXG15.0hWoOX8X9.:e:1001'

Tip: you can use makepasswd to generate encrypted passwords: echo -n "password" | makepasswd --crypt-md5 --clearfrom -

Mount all public keys in the user's .ssh/keys/ directory. All keys are automatically appended to .ssh/authorized_keys.

docker run \
    -v /host/id_rsa.pub:/home/foo/.ssh/keys/id_rsa.pub:ro \
    -v /host/id_other.pub:/home/foo/.ssh/keys/id_other.pub:ro \
    -v /host/share:/home/foo/share \
    -p 2222:22 -d atmoz/sftp \
    foo::1001

Put your programs in /etc/sftp.d/ and it will automatically run when the container starts. See next section for an example.

If you are using --volumes-from or just want to make a custom directory available in user's home directory, you can add a script to /etc/sftp.d/ that bindmounts after container starts.

#!/bin/bash
# File mounted as: /etc/sftp.d/bindmount.sh
# Just an example (make your own)

function bindmount() {
    if [ -d "$1" ]; then
        mkdir -p "$2"
    fi
    mount --bind $3 "$1" "$2"
}

# Remember permissions, you may have to fix them:
# chown -R :users /data/common

bindmount /data/admin-tools /home/admin/tools
bindmount /data/common /home/dave/common
bindmount /data/common /home/peter/common
bindmount /data/docs /home/peter/docs --read-only

The biggest differences are in size and OpenSSH version. Alpine is 10 times smaller than Debian. OpenSSH version can also differ, as it's two different teams maintaining the packages. Debian is generally considered more stable and only bugfixes and security fixes are added after each Debian release (about 2 years). Alpine has a faster release cycle (about 6 months) and therefore newer versions of OpenSSH. As I'm writing this, Debian has version 6.7 while Alpine has version 7.4. Recommended reading: Comparing Debian vs Alpine for container & Docker apps