Uncloud’s docs are great, but a few things are buried a bit. Hence a simple list of things that can improve your interactions with Uncloud.

SSH ProxyJump⌗

Sometimes you can not directly connect to a cluster, you first have to SSH into a host that is directly connected to a cluster. If this is the case use a SSH proxy jump (see ssh(1)). This allows you to, e.g. use a local docker to build images that can then be pushed to the cluster.

When connecting to a cluster it make sense to use a proxy jump host. In your ~/.ssh/config add:

Host uncloud*
    ProxyJump xxxxx.science.ru.nl

Where all my uncloud hosts are named, uncloudXXX, the above says use xxxxx.science.ru.nl as the proxy jump host.

If ssh-ing into the proxy jump host is difficult as well, due to a 2nd factor use an ControlMaster (see ssh(1)):

Host xxxxx.science.ru.nl
ControlMaster auto
    ControlPath ~/.ssh/%r@%h-%p.sock
    ControlPersist 10m

SSH Keys⌗

(SSH) keys used to authenticate against the Uncloud cluster must not have a passphrase. You can remove a passphrase with ssh-keygen -p -f /path/to-key-file and then set an empty one.

Using a specific key can be done by using a ssh_key_file in your uncloud/config.yaml. This should point to your identity file (the one without the .pub extension).

Docker Login⌗

Sometimes you need to reference an image that is hosted inside a registry that requires authentication. In that case use the local docker login to login. Those credentials are automatically pushed to the cluster and there it will be able to pull the image!

Uncloud socket⌗

Do not in your compose.yaml mount the Uncloud socket from /run/uncloud/uncloud.sock:/run/uncloud/uncloud.sock, if dockerd start earlier than the uncloud daemon it will create a directory instead of a socket and will fail the uncloudd startup. I.e. don’t do the following:

services:
  myserver:
    image: myimage
    volumes:
      - /run/uncloud/uncloud.sock:/run/uncloud/uncloud.sock
...

If you must get access to the uncloud socket, mount the entire directory:

services:
  myserver:
    image: myimage
    volumes:
      - /run/uncloud:/run/uncloud
...