Windows¶

Windows works both ways: as a machine you watch, and as the machine you run fleet from. Every command is run end to end on Windows in CI, from scripts as an agent runs them and at a real terminal as you do.

A Windows machine you watch¶

It needs OpenSSH Server and nothing else. Install it from Settings → System → Optional features, or in an administrator PowerShell:

Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
Start-Service sshd
Set-Service sshd -StartupType Automatic

Tailscale's SSH server does not run on Windows, so even on a tailnet a Windows machine is reached through its own OpenSSH server — by its tailnet name or address — and lets you in with your key.

Put your key on it once. fleet connects with your key, as ssh does, and manages no access itself; Windows' sshd reads keys from one of two files, depending on the account:

The account you log in as	The file sshd reads
a normal user	`C:\Users\you\.ssh\authorized_keys`
an administrator (most Windows logins)	`C:\ProgramData\ssh\administrators_authorized_keys`, shared by every administrator, and ignored unless only SYSTEM and Administrators can write it

Both mistakes — the key in the wrong file, or the right file with the wrong permissions — fail silently: the key is there and does not work. fleet doctor NAME prints the exact PowerShell line for each case, with your key in it; the lines are also in Reaching your machines.

Then add it like any other machine: "add ssh me@192.168.1.20", or fleet add "ssh me@192.168.1.20".

fleet notices from the first probe that the machine runs Windows and adapts; you never say so:

It is measured with PowerShell instead of a POSIX shell, and a reading writes nothing there.
fleet ssh box -- dir passes the command to the remote shell as it is, rather than wrapping it for a shell that is not there. The remote command's exit code comes back.
fleet edit box --path models=D:\models writes the machine's notes to %LOCALAPPDATA%\fleet\machine.yaml; a machine-wide file can sit in %ProgramData%\fleet\machine.yaml (more).
NVIDIA cards and their jobs are read with nvidia-smi, as on Linux. AMD cards are not read on Windows yet.

Running fleet on Windows¶

Install it from PowerShell:

powershell -ExecutionPolicy ByPass -c "irm https://raw.githubusercontent.com/lion-zhang/fleet/main/install.ps1 | iex"

Open a new terminal afterwards so fleet is on your PATH. fleet uses Windows' own OpenSSH client (ssh.exe), with your keys in C:\Users\you\.ssh and the ssh-agent service if you run it.

fleet ssh NAME gives an interactive session that owns the keyboard until you exit; Ctrl+C goes to the remote program, not to fleet.
fleet top runs in Windows Terminal and the classic console; q quits.
fleet update updates this machine in the background, once the command has exited: Windows cannot replace a program while it runs. It takes a minute; fleet --version shows the result, and update.log in fleet's state folder says how it went.
Connections are not shared between commands, because Windows' OpenSSH has no ControlMaster; each reading pays for its own handshake.

Quote what you send. PowerShell expands $HOME inside double quotes and, from 7.4, a leading ~ in any argument, before fleet sees it. Commands for another machine go in single quotes: fleet ssh gpu-box -- 'ls ~/proj'. See Running work.

No ssh-copy-id. Windows has none, so fleet add does not offer to put your key on a machine that refuses it. fleet doctor NAME prints the line to run on that machine instead.

If something does not work¶

What you see	What to do
`fleet` is not found after installing	Open a new terminal.
`ssh: connect to host … port 22: Connection refused`	sshd is not running there: `Start-Service sshd`.
a Windows machine refuses a key you know you added	It is in the wrong file, or the administrators file has the wrong permissions. `fleet doctor NAME` prints the right line.
`! this command contains C:\Users\…, this machine's home folder`	PowerShell expanded `$HOME` or `~` before fleet saw the command. Put the remote command in single quotes.
a `fleet-center` scheduled task, or firewall rules named `fleet center`	Left by fleet 0.5. See Upgrading from 0.5.