Direct SSH vs ssh_host in vmup

resolveTarget picks one of two modes. Mixing them in one command is rejected (--profile with --ssh-host).

How to set profiles: Point vmup at another VM.

Direct

Used when the profile has no ssh_host, and you did not pass --ssh-host / VMUP_SSH_HOST.

vmup builds:

ssh -p <port> -i <key> -o BatchMode=yes -o StrictHostKeyChecking=accept-new user@host <command>

File uploads reuse that ssh: the local file is piped to cat > <remote-file> so the spinner can count bytes as they are written.

BatchMode=yes refuses a password prompt. If the key is missing from authorized_keys, the command fails instead of hanging. accept-new adds unknown host keys; it does not blindly accept a changed key (OpenSSH still fails on mismatch).

The private key is checked on disk first: exists, readable, and not group/world-readable (Unix). That check is skipped in alias mode because vmup may not know which file OpenSSH will use.

Default user is ubuntu. Default port 22. Default key hint ~/.ssh/id_ed25519. Host has no default; without it, vmup tells you to run init.

SSH_AUTH_SOCK lets you omit key in config. vmup then passes no -i and relies on the agent. Port and user@host still come from the profile / env.

Alias (ssh_host)

Used when the profile sets ssh_host, or when you pass --ssh-host / VMUP_SSH_HOST.

ssh lab <command>

No -p, no -i from vmup. User, port, IdentityFile, ProxyJump, and HostName come from ~/.ssh/config. If ssh lab works in your terminal, this mode is the one that matches that behavior.

--ssh-host without a profile names the target ssh:<alias> in output. A saved profile keeps its real name (lab) even when that profile’s field is ssh_host.

A Host block that already sets BatchMode or accept-new is fine.

Remote paths and ~

vmup expands ~ via $HOME in remote shell snippets (mkdir, cat, mv, rm, the sweeper). Displayed agent paths keep the ~/vmup/… form.

Which to pick

Direct mode is the init wizard: you type IP, user, key. Good when this laptop’s only SSH client for that VM is vmup.

Alias mode is better when you already have Host stanzas (jumps, non-22 ports, hardware keys). Put ssh_host = "thatHost" on the profile and leave host unset.

A common failure: the profile still has host = "…" from init, you added a Host block, and you expected vmup to use it. Direct mode ignores ~/.ssh/config for identity and port. vmup profiles shows user@ip for direct and ssh_host=name for alias.