A: SSH is a protocol to connect/logging to a remote computer, and it is commonly used to execute commands or transfer files on a remote machine.
For that to work, you’ll need an SSH client and a server. You can type
ssh -V on your terminal to see if you have the client already installed (normally included in OSX or Linux distributions), if you are on windows, the most used client is PuTTY
Now, on the computer that you want to reach, you should have the SSH server, usually
sshd (or SSH Daemon), if you are running an operative system with systemd you can check if it is running by executing on the remote server
systemctl status sshd (and it should say “Active”).
If everything went well, and you have both, a client on your computer and a server on the other computer that you want to connect to, you can use the client (either
putty by specifying the address of the remote machine - an IP or hostname that resolves to the desire destination).
DVC needs to know the same information in order to establish a connection, and the way you configure it is by using the
remote add/modify command. Let’s say that we are using the following configurations:
So the way I can configure the SSH remote with DVC will be the following:
dvc remote add --default ssh-storage ssh://example.com/path/to/storage
dvc remote modify ssh-storage user mroutis
dvc remote modify ssh-storage port 22
dvc remote modify --local ssh-storage password 123456789
--local on the last command, this is important, because the
dvc remote command modifies the
.dvc/config file and this file is stored with Git, so, you can end up with this information on your GitHub/BitBucket/GitLab or whatever you use to distribute your code repository.
Instead of password the recommended way is to use SSH keys.
There’s a difference between the host
example.com and the URL I’m passing to DVC
ssh://example.com/path/to/storage DVC needs a URL with the following standard:
scheme://host/path, in this case, the scheme is
ssh, the host is the one we already have, and the path is the absolute path were DVC will be uploading the cache.
DVC will be uploading (
push ) and downloading (
pull) files from your remote, the URL
ssh://hostname/path/to/storage is just a way to tell DVC in which directory it will store the data. You can connect to your server with
PuTTY and then create a directory with the following command
mkdir /tmp/dvc-storage , now, if you configure DVC with the following URL
ssh://your-host-name-or-ip/tmp/dvc-storage when you
dvc push it will upload files to that directory that you created previously
/tmp/dvc-storage and when doing
dvc pull it will connect to the remote computer via SSH, go to that directory (
/tmp/dvc-storage/ ) and then download the files via SSH.