How to use PoSH or PowerCLI to SSH into network devices – wodSSH [Part 2]

 

In [part 1] of this series of posts, I explored SharpSSH, and how to use this to SSH into network devices via PowerShell or PowerCLI. I found this extremely useful, and managed to automate a process of retrieving some SHA1 SSL fingerprints from a few clusters of ESX hosts in the process. I did however find that loading the dll and functions necessary to get this bit of automation done was a little tedious. I had heard about wodSSH via the get-scripting podcast and decided I would need to take a look at this.

 

If you are planning on using wodSSH, you should start by downloading it here. Note that you should definitely buy a license if you are going to be using this for your job or day to day automation – the license is not to expensive if you consider the kinds of automation you could achieve with this! For this blog post I am just using the trial version in my lab environment at home to try out – the trial pops up a “nag screen” every now and then to indicate you are unlicensed. Once downloaded, install wodSSH and the libraries will now be available for use on your machine.

 

Download the script below, or take a look at it in the Syntax Highlighted area below – this is an example of how I was able to SSH into a cluster of ESXi hosts and run a remote command via SSH through PowerCLI. In this example, a table is returned with Host names, along with their SHA1 fingerprint information. It is possible to retrieve this info (as of ESXi 5 I believe) in PowerCLI, but for this example I just wanted to demonstrate the use of SSH and PowerShell / PowerCLI.

 

[download id=”14″]

 

$login = "root"
$password = "yourrootpassword" 

$Report = @()
$VMHosts = Get-VMHost | Where {$_.ConnectionState -eq "Connected"} | Sort Name

foreach ($vmhost in $VMHosts) {
	$hostname = $vmhost
	$ssh = New-Object -ComObject "weOnlyDo.wodSSHCom.1"
	$ssh.Hostname = $hostname
	$ssh.Login = $login
	$ssh.Password = $password
	$ssh.Blocking = 1
	$ssh.Protocol = 4
	$ssh.Timeout = 25
	$ssh.Connect($hostname)
	$ssh.WaitFor("regex:[$%#>] $")
	$cmdresult = $ssh.Execute("openssl x509 -sha1 -in /etc/vmware/ssl/rui.crt -noout -fingerprint`r`n","regex:[~#]")
	$ssh.Disconnect()
	$temp = $cmdresult | select-string -pattern "SHA1 Fingerprint="
	Write-Host $cmdresult -ForegroundColor Green
	$row = New-Object -TypeName PSObject -Property @{
		SHA1 = $cmdresult
		HostName = $vmhost
	}
	$Report += $row
}
$Report

 

You will notice that on line 09, we load the wodSSH library using the New-Object cmdlet. After this we continue to setup some properties for our $ssh connection object. A regex check is used to determine when are connected to a host and have an SSH shell prompt ($ssh.WaitFor(“regex:[$%>;] $”).  We then use $cmdresult to capture the result of running an SSH command via our connection to our current ESXi host. To finish capturing the output of the command on our remote host, we use a regex check again (“regex:[~#]”). You’ll notice that the actual command is also on this line, i.e. line 18 (openssl). After the result is captured, we disconnect our SSH session, then proceed to build our small report array. At the end of the script, we output the $Report array to the screen.

 

 

As far as I can see, the wodSSH library can open up a whole new world of automation for you in the data centre. Think of the possibilities – you could automate just about everything, from switches, routers, Linux/Unix hosts / ESXi Hosts to iLO / DRAC and other management cards. Essentially, anything that accepts commands via SSH! If you have any automation stories using wodSSH, or just PowerShell or PowerCLI in general, I would love to hear about them – so feel free to drop a comment or two on this post.