Haumea: znapzend configuration

Setting a server to receive snapshots

In this document, I call the receiving server "target". The receiving end must run ZFS. In this snippet, I assume the following about "target":

• the backups will be stored in a pool named mass
• the dataset will be named mass/nixos-org/haumea
• it will have a user named "nixosfoundationbackups"

In the receiving server's configuration, define a user like this:

{
  users.users.nixosfoundationbackups = {
    # the user needs to be able to execute commands remotely, thus having a shell:
    isNormalUser = true;
    openssh.authorizedKeys.keys = [
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOyyr/4fMKQ1fwa5DjFVIHQLchr4EKcOWEI++gYBTbWF root@haumea"
    ];
  };
}

Then create the dataset:

target# zfs create mass/nixos-org/haumea
target# zfs set canmount=off mass/nixos-org/haumea
target# zfs allow -u nixosfoundationbackups create,destroy,mount,receive,userprop mass/nixos-org/haumea

Also look up the public ed25519 key on the server:

target# cat /etc/ssh/ssh_host_ed25519_key.pub
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKKUSblYu3vgZOY4hsezAx8pwwsgVyDsnZLT9M0zZsgZ root@nixos

In Haumea's Configuration

Add the host key:

{
  services.ssh = {
    knownHosts = {
      rob-backup-server = {
        hostNames = [ "targetserver" ];
        publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKKUSblYu3vgZOY4hsezAx8pwwsgVyDsnZLT9M0zZsgZ";
      };
    };
  };
}

Then edit Haumea's expression and add your server to Haumea's list of targets:

{
  services.znapzend = {
    zetup = {
      "rpool/safe" = {
        destinations.your-servers-name = {
          plan = "1hour=>5min,4day=>1hour,1week=>1day,1year=>1week,10year=>1month";
          host = "nixosfoundationbackups@your-servers-address";
          # Note: the `/safe` suffix is intentionally not created automatically. Do not omit the `/safe`
          # suffix when adding a server, in case we need to sync more top level datasets in the future.
          dataset = "mass/nixos-org/haumea/safe";
        };
      };
    };
  };
}