Ability to add your own instances to pools/dstack

[TheBits]

After we finish pool support, we will be ready to add our own servers to the pool. This is necessary for a particular set of users that have their own bare metal servers.

To add a server, we need to use the dstack pool add command in the same way as we add cloud instances with additional arguments:

dstack pool add \
    --remote \
    --remote-host 192.168.88.131 \
    --remote-port 22 \
    --ssh-user=root \
    --ssh-identity ~/ssh_key.pub

I will explain the new arguments: --remote - Adding a running server --remote-host 192.168.88.131 and --remote-port 22 - Connection detils --ssh-user=root and --ssh-identity ~/ssh_key.pub - Credentials for ssh

To add the server, we need to go through the following steps.

• connect via ssh to the server
• install dstack-shim
• add dstack-shim.service to the systemd

After install, dstack-shim should retrieve server resources and save them to the InstanceModel on the dstack server. This information about server resources will be provided to the user via "dstack pool ps" command.

[r4victor]

@TheBits for multi-node support, dstack also needs to know VMs internal ips.