Understanding Remoting

The Protocol

PowerShell uses a protocol that you might have never heard of, the Web Services for Management(WSMan), which is one of the builtin PSProvider on Windows. WSMan is Windows specific feature, so as PowerShell came into the cross-platform world, Microsoft decided to support SSH which is more commonly used over industries. Microsoft made effort to bring SSH to Windows world, they're maintaining a fork of SSH in github

NOTE

openssh is builtin since certain version of Windows 10.

Connect to Remote

No matter which protocol you use with PowerShell, it has a unified cmdlet to connect to one. Of course this requires PowerShell available on both sides.

• Using SSH

# login as <user> on <ip>
Enter-PSSession -HostName <host> -UserName <user> -Port <port>
# or use a short syntax
Enter-PSSession -HostName <usr>@<host>

• Using WSMan

# -ComputerName used instead for connection by WSMan
Enter-PSSession -ComputerName <host> -UserName <user>

Optionally, you can store the session as variable instead of entering it by New-PSSession.

$session = New-PSSession -HostName <host> -UserName <usr>

Disconnect from Remote

Exit-PSSession

Execute Command on Remote

• Execute a same command on one or more remotes.

Invoke-Command -HostName <host1>[,<host2>, ...] -UserName <usr> -ScriptBlock { <cmd> }

• Execute on a persistent session

$session = New-PSSession -HostName <host> -UserName <usr>
icm -Session $s -ScriptBlock { <cmd> }

NOTE

Invoke-Command returns deserialized object converted from transferred xml from remotes, it reflects data on remote only. You should only aggregate format it without mutating the values. Enter-Session does enter a PowerShell session, so it operates on a real PowerShell instance just like what you can do with SSH.