Goals

  1. Configure the NAS to accept SSH and Rsync connections

  2. Enable SSH with pub-Key

  3. Deploy pub key

  4. Synchronize files with rsync

Prerequisites

We assume, that the Synology NAS basic configuration has been applied and that a shared directory is ready to be our sync target.

We will be synchronizing the directory /tmp/samples to the NAS directory /volumes/samples.

Synology NAS Setup

First of all we need to enable some services on our NAS.

Enable SSH and Rsync on the NAS

SSH is enabled at Control Panel → Terminal & SNMP → Terminal:

synology-ssh-activation

Rsync is enabled at Control Panel → File Services → rsync:

synology-file-services-rsync
Figure 1. Activating rsync

user must have admin permission

Activate User Homes on the NAS

Because we want to store our SSH pub key in our NAS user’s home directory, we need to enable user-homes.

The option is found here Control Panel → User → Advanced → User Home:

synology-activate-user-homes
Figure 2. Activating User Homes

Setup SSH Keys and Configuration

We’re setting up a new SSH key and adding an entry for the NAS in our SSH configuration for easier connections.

Create a new SSH Key, add SSH Config

We’re adding a new SSH key, storing the public and the secret key in our .ssh directory.

ssh-keygen -t rsa -b 2048 -f ~/.ssh/rsync-nas

We’re adding the following section to our ~/.ssh/config:

Host nas
HostName 192.168.xxx.xxx (1)
Port 22
User mybackupuser (2)
IdentityFile ~/.ssh/rsync-nas

  1. Replace with your NAS station’s IP address

  2. Replace with your user on the NAS station

Upload SSH Key to Synology NAS

We’re using ssh-copy-id to upload our keys to the NAS.

Just to be safe we’re forcing ssh to use password-authentication as only method (-o PreferredAuthentications=password -o PubkeyAuthentication=no).

ssh-copy-id -o PreferredAuthentications=password -o PubkeyAuthentication=no -i ~/.ssh/rsync-nas mybackupuser@192.168.xxx.xxx
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/xxx/xxx/.ssh/rsync-nas.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
mybackupuser@192.168.xxx.xxx's password:

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh -o 'PreferredAuthentications=password' -o 'PubkeyAuthentication=no' 'mybackupuser@192.168.xxx.xxx'"
and check to make sure that only the key(s) you wanted were added

By now we should be able to connect to our NAS using the following command:

ssh nas

Synchronizing Files with rsync

Now we’re ready to synchronize files with rsync:

rsync -avuz -e '/usr/bin/ssh -i /home/localuser/.ssh/rsync-nas' /tmp/samples/* mybackupuser@192.168.xxx.xxx:/volume1/samples

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