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Add a host

Any Linux host you can reach with ssh can run sessions: amd64 or arm64, with sh, uname and sha256sum. systemd is used when it is there, so sessions survive a logout and come back after a reboot.

With the guided setup

simstim setup asks where agents will run, connects the host, then offers to install agents and log in to them (getting started). To give it the host at once:

simstim setup --host my-server

--host takes a saved host, a Host from your SSH config, or user@host. The rest of this page adds a host by hand.

A host from your SSH config

If ssh my-server works, then:

simstim host add my-server --yes

The client uses the system ssh, so everything in ~/.ssh/config applies: ProxyJump, keys, agents, certificates and Tailscale. It never edits your SSH config.

A host by address 

simstim host add box admin@203.0.113.7 --yes

A repo’s own SSH config

Some teams keep an SSH config in a repository, with jump hosts and names of their own. Name it with --ssh-config:

simstim host add dev-vm dev-vm --ssh-config ~/src/infra/ssh/config --yes

What host add does

  1. Checks that the host answers, and finds its system and CPU.
  2. Asks before it installs the helper, unless you pass --yes, then uploads it into ~/.local/share/simstim/bin/ and checks its SHA-256.
  3. Turns on systemd’s linger for your user, so sessions keep running when you log out, and installs the unit that restores sessions after a reboot.
  4. Saves the host in hosts.toml (configuration).
  5. Lists the agents it finds. In a terminal, when a first-class or supported agent is missing, it shows the agent checklist: type the numbers of the agents to install (install agents). --yes skips the checklist.

Check a host 

simstim host test my-server
simstim host doctor my-server

host doctor lists what the host has and what is missing: systemd, linger, the agents and the helper. host doctor --fix offers to fix what it can (troubleshoot).