A function to lookup Host System friendly name by MoRef using PowerCLI

In a recent blog post, I showed a simple method of outputting a list of hosts with their friendly names, as well as their MoRef (Managed Object Reference) names alongside eachother, enabling you to match up which host belongs to which MoRef. I wanted to take that a little further, with a function that is able to return the friendly name of a host’s MoRef that is input into the function. I have used this is a larger reporting script, where I can only get the MoRef of a host via it’s property within a cluster object. Basically, I look for any Failover hosts (admission control policy), which is an array, and the hosts are listed as indexed objects of this array. They are also only displayed as MoRef names, so at this point, instead of inserting the MoRef into my results, I insert the MoRef into this function, return the friendly name, and input this instead. Which allows the person reading the report to easily identify the host! $cluster.ExtensionData.Configuration.DasConfig.AdmissionControlPolicy.FailoverHosts <- In this example, $cluster is a particular cluster using the “specify a failover host” policy, and “FailoverHosts” is the array, with each object within containing a host MoRef. For example FailoverHosts[0].Value would be one instance, and may equate to “HostSystem-host-28” for example.   So here is the function. It takes two mandatory parameters: -MoRef (the MoRef of the host in question of course), and -Cluster (the name of the Cluster to do the lookup in) – the function loops through each host in this cluster to look for a host that matches the input MoRef.

Function Get-VMHostByMoRef() {

<#
.SYNOPSIS
Fetches host name by input MoRef and Cluster to look in

.DESCRIPTION
Fetches host name by input MoRef and Cluster to look in

.PARAMETER MoRef
The MoRef of the host system

.PARAMETER Cluster
The name of the cluster to do the lookup in

.EXAMPLE
PS F:\> Get-VMHostByMoRef -MoRef HostSystem-host-28 -Cluster MyCluster01

.LINK
http://www.shogan.co.uk

.NOTES
Created by: Sean Duffy
Date: 22/02/2013
#>

[CmdletBinding()]
param(
[Parameter(Position=0,Mandatory=$true,HelpMessage="Specify the Host MoRef name you would like to query for it's friendly name.",
ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)][String]$MoRef,[Parameter(Position=1,Mandatory=$true,HelpMessage="Specify the Cluster to search hosts in.",
ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)][String]$Cluster
)

process {

$AllHosts = Get-Cluster $Cluster | Get-VMHost
$thehost = $AllHosts | Where {$_.ExtensionData.MoRef -match $MoRef} | Select-Object -Property Name

return $thehost

}
}

Here is a quick sample of the output when called directly from the PowerCLI prompt (note the MoRef of “host-22” used to find the real host name of “esxi02.homelab.local”: Hopefully this may be of use to some – add it to your PowerCLI script/function toolkit or throw it into your PowerShell $profile for easy access in the future!

vMetrics for WordPress blogs updated to version 1.1

I spent a little bit of time updating my vMetrics plugin for WordPress blogs. To give you a brief run-down, vMetrics allows you to display information from your VMware vCenter Cluster or ESX hosts / lab on your WordPress blog. It works with vSphere 4, 5 and 5.1.

 

 

In version 1.1 I have made the following changes:

Change log for version 1.1:

  • Added new metrics section for hardware information (Model and Vendor of first host in cluster – this is editable in the PowerCLI script)
  • Added configurable widget title section for Hardware
  • Updated PowerCLI updater script to have a DO WHILE loop (allowing you to run the script once on a management machine and it will keep updating your blog vMetrics every 30 minutes. (The script is called once every half hour). Thanks @dawoo for the idea 🙂
  • Added PowerCLI section to send the vendor and model type of the first ESX host it finds back to vMetrics so that you can display this information in the widget too
  • Cleaned up PHP in main plugin code

You can take a look at the main plugin page here or use the links below to download the latest version right away. Installation and configuration steps can be found on the main plugin page.

Latest version downloads (get the plugin and updater script):

[download id=”22″]
[download id=”23″]

Adding vCenter Server to Active Directory domain and disconnecting ESXi hosts issue

The other day I came across this issue, it was quite late at night so it took me a little longer than I would have liked to realise what the issue actually was.

I had a vCenter 5.0 server which had not been joined to the local Active Directory domain. My goal was to get this added to the rest of the AD domain. After adding the vCenter server to the domain, rebooting, and checking that all the VMware services had started up correctly afterwards, I connected the vSphere client and saw that all the ESXi hosts were in a disconnected state.

At this point I tried right-clicking a host and manually connecting it – this worked, but only 60 seconds or so, and then it disconnected again. Whilst it was connected it was manageable, and of course all the VMs on each host were still fine. I tried restarting management agents on a host and retrying the procedure, but this didn’t help either. My next step was to reboot an ESXi host that didn’t have anything critical running. Still nothing at this point.

So I decided to consult the VMware vpxd log files on the vCenter server. Consult this VMware KB article to see where to find these logs.

Before opening the latest vpxd.log file, I tried the reconnect on a host again using the vSphere client, and watched for the disconnect. At the exact time I noticed the host appear disconnected again, I noted down the time on the system clock, then opened the vpxd logs to navigate to this time and take a look. Here is what I found:

2013-01-04T00:00:22.121Z [02504 warning 'Default'] [VpxdInvtHostSyncHostLRO] Connection not alive for host host-28
2013-01-04T00:00:22.121Z [02504 warning 'Default'] [VpxdInvtHost::FixNotRespondingHost] Returning false since host is already fixed!
2013-01-04T00:00:22.121Z [02504 warning 'Default'] [VpxdInvtHostSyncHostLRO] Failed to fix not responding host host-28
2013-01-04T00:00:22.121Z [02504 warning 'Default'] [VpxdInvtHostSyncHostLRO] Connection not alive for host host-28
2013-01-04T00:00:22.121Z [02504 error 'Default'] [VpxdInvtHostSyncHostLRO] FixNotRespondingHost failed for host host-28, marking host as notResponding
2013-01-04T00:00:22.126Z [02504 warning 'Default'] [VpxdMoHost] host connection state changed to [NO_RESPONSE] for host-28

This clearly shows the issue and points to it being a connectivity issue of some sort. Looking up these specific errors led me over to this VMware KB article, and it was at this point that it suddenly dawned on me – with the late night I had carelessly overlooked the Windows Firewall. Of course, Windows Firewall has settings for Windows Domains too, and of course this server had just joined the domain, so existing Firewall policies in place for vCenter that were previously on “public” settings, were now not enabled for “Domain”.

Timing the issue also revealed that it was 60 seconds before hosts disconnected again. So the issue here was that port 902 used for the host heartbeat between vCenter and the ESXi hosts was being blocked on the vCenter firewall. Unblocking this by simply enabling the rule for “Domain” fixed the issue and as soon as that was applied, all hosts reconnected by themselves. Of course I also took the time to ensure other vCenter firewall exceptions were correctly configured.

 

 

To fix, I just enabled the Domain profile that the firewall rule applies to.

 

Lastly, when examining VMware log files and settings, you may come across references to VMs, Hosts, or other VMware “objects” named as “host-28” or “vm-07” for example. These are VMware’s way of keeping reference of objects by what is called a MoRef, or “Managed object reference”. You may know host-28 as esxi03.yourdomain.local for example, so I thought I would include a handy tip for working out the Managed Object Reference name of an ESXi host to help with those vpxd.log diagnostics. Let’s say you find an interesting error mentioning moref “host-28”. You don’t know which host this is, so you can use PowerCLI to work out the morefs of hosts in a cluster and then match up the reference to the actual host name. Use this bit of script to achieve this:

 

Get-VMHost | Sort Name | Select Name,@{Name="MoRef";Expression={$_.ExtensionData.MoRef}}
Working out the MoRef of hosts using PowerCLI

 

 

ESXi Host Backup & Restore GUI Utility (PowerCLI based) updated to 1.2

A quick post today to just mention that I have updated my ESXi 5.0 / 5.1 Host Backup & Restore GUI utility to version 1.2.

 

There are a couple of improvements in 1.2 based on feedback received in the comments I have received about the utility. The main improvement introduces a function in the script which backs the GUI to check that ESX hosts are valid before attempting to backup or restore these. You can check the utility out over on it’s page here.

 

Updates (29-12-2012) – version 1.2:

  • Added ESX/ESXi host validation into utility – will now test that the host is valid and either connected or in maintenance mode before attempting backup or restore (See the script’s new “Check-VMHost” function for those interested)
  • Minor UI improvements

 

Using plink to modify ESXi host configuration files via SSH from a PowerCLI script

I am a big advocate of automation and saving time with a good script. Whenever I can find a task that is fairly lengthy, and is likely to be repeated in future, I always consider scripting it. There are many way to configure an ESXi host when it comes to writing build or automation scripts. In fact, I often feel we are quite spoilt for choice. Here are just some of the tools we have available to use:

  • PowerCLI
  • esxcli
  • vMA
  • vCLI

I was working on a build configuration script the other day using PowerCLI and found the need to edit some configuration files on the hosts. I wanted to edit the configuration file /etc/vmware/config during the execution of a single PowerCLI script without needing to stop the script or have an additional step to do myself. The following is what I came up with to achieve this:

  • Configure host as normal using PowerCLI
  • Use PowerCLI to start SSH service on host
  • execute plink script to connect to host, run command via SSH, then disconnect
  • Use PowerCLI to stop SSH service on host
  • Continue with rest of PowerCLI script

 

Plink is a command line connection tool – essentially a command line version of PuTTy. You can call it from dos prompt and issue it with a single, (or list) of commands to run once connected to a specified host. You can download Plink over here.

 

So without further ado, let’s take a look at the script as I described above.

# At start of our script we ask for the host's IP or name (this could be automated if you like)
$hostIP = Read-Host "Enter ESX host IP/dns name: "
$vmhost = Get-VMHost $hostIP

# Start the SSH service
$sshService = Get-VmHostService -VMHost $vmhost | Where { $_.Key -eq “TSM-SSH”}
Start-VMHostService -HostService $sshService -Confirm:$false

# Use SSH / plink to configure host with some additional script
cmd /c "plink.exe -ssh -pw HOSTROOTPASSWORD -noagent -m commands.txt root@$hostIP"

# Stop SSH service
Stop-VMHostService -HostService $sshService -Confirm:$false

 

As you can see, we start off by asking for the host IP or name, this is the only bit of manual input, but even this could be automated. The script then finds the SSH service on the host, and starts it. After this, the script calls the plink.exe file via cmd /c and connects using the root user@ the host’s IP as we entered at the beginning of the script over SSH. Plink is pointed to a commands.txt file (previously placed in the script execution folder), which contains the actual lines of bash script to be executed on the ESXi host via SSH.

Here is the content of the commands.txt file that I refer plink.exe to use (as an example, this bit of script enables copy/paste operations on all VMs running on this host in the guest OS’ console, as per VMware KB 1026437), but could contain any other commands you wish to execute on the ESXi host over SSH.

echo 'isolation.tools.copy.disable="FALSE"' >> /etc/vmware/config
echo 'isolation.tools.paste.disable="FALSE"' >> /etc/vmware/config

 

* Note two very useful techniques show by Alan in the comments section below, showing how to automatically download plink.exe if it is not available when the script is run, and also how to accept the SSH fingerprint key request by piping Y to plink.exe via the script – check out Alan’s blog post here for more detail.

Issue using the Count method to count objects with PowerShell 2.0

 

I came across a small issue with a little helper script I wrote to count vSphere objects using PowerCLI this morning. It’s been a couple of a weeks since I last did a blog post – things have been very busy, so I have not been able to commit much time over the last few weeks to blogging. As such, I thought I would do a quick post around this small issue I came across earlier. It has more than likely been covered off elsewhere, but will be a good reference point to come back to if I ever forget!

 

So to the issue I saw. Essentially, if an object count is 1 or less, then the object is returned as the object type itself. For example, where only one Distributed Virtual Switch exists in a vSphere environment, and we use the cmdlet, Get-VirtualSwitch -Distributed, a single object is returned of BaseType “VMware.VimAutomation.ViCore.Impl.V1.VIObjectImpl“.

 

However, if we had more than one dvSwitch, then we would get a BaseType of “System.Array” returned.

 

We are able to use the Count() method on an array with PowerShell version 2.0, but are not able to use the Count() method on a single object. The work around I found here (when using PowerShell 2.0) is to cast the object type specifically as an array.

So in the case of our dvSwitch example above, originally we would have done:

@dvSwitchCount = (Get-VirtualSwitch -Distributed).Count

 

To cast this as an array, and therefore having an accurate count of the objects, whether there are no members, one member, or more, we would use:

@dvSwitchCount = @(Get-VirtualSwitch -Distributed).Count

 

Note the addition of the “@” sign – used to cast the variable as an array.

Jonathan Medd also kindly pointed out that this is fixed with PowerShell 3.0 – have a read of the new features to see the addition that allows .Count to be used on any type of object over here.