Show Currently Connected vCenter Servers in PowerCLI 5.0.1

PowerCLI 5.0.1 was recently released and vNuggs decided to check it out. Almost immediately we noticed something was missing. PowerCLI was no longer reporting in the title bar the vCenter server(s) to which we were connected.

Example of a single connected server before PowerCLI 5.0.1:

Example of multiple connected servers before PowerCLI 5.0.1:

AC decided to make a quick post to the PowerCLI community to see if others had noticed it and was hoping the PowerCLI team would respond as to whether this was intentional or not and what the future plans are for this functionality.  So far, no word from the team, but others have noticed the change as well.

However, in the meantime, we decided to solve the problem ourselves with some functions.  The first function is the one that does all the real work--ChangeTitleBar:

## Function to change title bar to reflect currently connected vCenters
## Author: vNugglets.com -- Jan 2012

function Change-TitleBar() {
    ## check to see if there are any currently connected servers
    if ($global:DefaultVIServers.Count -gt 0) {
        ## since there is at least one connected server, modify the window title variable accordingly
        $strWindowTitle = "[PowerCLI] Connected to {0} server{1}:  {2}" -f $global:DefaultVIServers.Count, $(if ($global:DefaultVIServers.Count -gt 1) {"s"}), (($global:DefaultVIServers | %{$_.Name}) -Join ", ")
    }
    else {
        ## since there are no connected servers, modify the window title variable to show "not connected"
        $strWindowTitle = "[PowerCLI] Not Connected"
    }
    ## perform the window title change
    $host.ui.RawUI.WindowTitle = $strWindowTitle
}

In line 6 the function merely checks the Count property of the array DefaultVIServers to ensure that you are connected to at least one server, then updates a variable with the new window title text in line 8. Note that we are omitting the name of the connected user.  We went this route to keep the function simple and because even VMware didn't include this info when connected to multiple servers (see screen shots above) and in the end, it is not something we find all that important/useful. It could simply be added by using the User property of the DefaultVIServers variable.

In line 12 (the "else" portion of the "if" statement) we just set the variable to what we selected as our default window title text.  Change this to your own preference (note that it doesn't bother reporting the PowerCLI version either, but that's easy enough with the Get-PowerCLIVersion cmdlet).

Finally, line 15 actually sets the window title to the defined value.  Now you just need to place this function in your PowerShell profile and make calls to it when you connect to/disconnect from VI servers.  You can do this by writing custom functions for Connect-VIServer and Disconnect-VIServer as follows:

## Modified "Connect- and Disconnect-VIServer" functions that call "Change-TitleBar" function
## Author: vNugglets.com -- Jan 2012

## Function for the "Connect-VIServer" cmdlet
function ConnectServer([string] $strVCenterName) {
    Connect-VIServer -Server $strVCenterName
    Change-TitleBar
}

## Function for the "Disconnect-VIServer" cmdlet
function DisconnectServer([string] $strVCenterName = "*") {
    Disconnect-VIServer -Server $strVCenterName -Confirm:$false
    Change-TitleBar
}

There is absolutely nothing fancy about these functions and they are not intended as direct feature-for-feature replacements of the actual Connect- and Disconnect-VIServer cmdlets.  The ConnVIServer function simply takes a string parameter and calls the actual Connect-VIServer cmdlet with that string specified as the server to connect to.  It then calls the Change-TitleBar function to do the title bar magic.  The DisconnVIServer function does the same, except in this case we've set a default parameter value of "*" just for convenience when you want to disconnect from all connected servers.  You'd merely type DisconnVIServer and it would immediately disconnect from all servers.

Lastly, it is probably a good idea to make a call to Change-TitleBar somewhere after the function definitions in your PowerShell profile.  Then it'll set the "default" title bar text as you launch PowerShell since the initial text with PowerCLI 5.0.1's initialization script just shows the name of the product and version.

Working with multiple default servers

Connect-VIServer has a new behavior/feature as of the 4.0 Update 1 release: "Working with multiple default servers." So what? So this: connecting to hosts that are not managed via a vCenter instance and taking actions against inventory items.

"vSphere PowerCLI supports working with multiple default servers. If you select this option, every time when you connect to a different server using Connect-VIServer, the new server connection is stored in an array variable together with the previously connected servers, unless the -NotDefault parameter is set. This variable is named $DefaultVIServers and its initial value is an empty array. When you run a cmdlet and the target servers cannot be determined from the specified parameters, the cmdlet runs against all servers stored in the array variable. To remove a server from the $DefaultVIServers variable, you can either use Disconnect-Server to close all active connections to the server, or modify the value of $DefaultVIServers manually."
(from http://www.vmware.com/support/developer/windowstoolkit/wintk40u1/html/Connect-VIServer.html)

An example of the new behavior in action:

PS C:\> Connect-VIServer vcenter4.local
WARNING: There were one or more problems with the server certificate:
* The X509 chain could not be built up to the root certificate.

Login Information
Please supply user credentials.
User: vNuggsAdmin
Password for user vNuggsAdmin:  ***********

Name                                    Port                       User
----                                    ----                       ----
vcenter4.local                          443                        vNuggsAdmin


PS C:\> Connect-VIServer standAloneHost0.local
WARNING: There were one or more problems with the server certificate:
* The X509 chain could not be built up to the root certificate.
* The certificate's CN name does not match the passed value.

Login Information
Please supply user credentials.
User: root
Password for user root:  ***********

Working with multiple default servers?

  Select [Y] if you want to work with more than one default servers. In this case, every time when you connect to a different server using Connect-VIServer, the new server connection is stored in an array variable together with the previously connected servers. When you run a cmdlet and the target servers cannot be determined from the specified parameters, the cmdlet runs against all servers stored in the array variable.
  Select [N] if you want to work with a single default server. In this case, when you run a cmdlet and the target servers cannot be determined from the specified parameters, the cmdlet runs against the last connected server.
  You can change your preference at any time using the DefaultServerMode parameter of Set-PowerCLIConfiguration.
[Y] Yes  [N] No  [S] Suspend  [?] Help (default is "Y"): Y

Name                                    Port                       User
----                                    ----                       ----
standAloneHost0.local                   443                        root


PS C:\> $DefaultVIServers
Name                                    Port                       User
----                                    ----                       ----
standAloneHost0.local                   443                        root
vcenter4.local                          443                        vNuggsAdmin


PS C:\>

At this point, running a cmdlet that is not VIServer specific (as determined by the specified parameters) runs against all the servers to which this session is connected, namely "standAloneHost0.local" and "vcenter4.local." So, you can now act on all items in these servers' inventory.

A few notes:

• If connecting to a vCenter instance and a host which is managed by that vCenter instance, cmdlets will return the items in the host's inventory twice: once when the cmdlet runs against the vCenter server, and once when the cmdlet runs against the host itself, since both will be in the $DefaultVIServers array.
• The help for "Connect-VIServer" cmdlet mentions that "Working with a single default server is deprecated and will be removed in a future release.", so the time is now to familiarize one's self with multiple VIServer behavior.
  
• As the message in the Powershell session above reads, one can adjust the single/multiple VIServer behavior using the "Set-PowerCLIConfiguration" cmdlet, for which the help is straightforward.

Additionally, as you will probably notice, the title bar of your PowerShell session indicate that you are connected to X number of servers, along with their names.

A simple example of the usefulness of this new feature: connect to several non-vCenter managed VIServers and act against all items associated with said hosts. We are using a Powershell Credential object in this example so as not to need to enter credentials for each host (which assumes that there is a common account across them all) and to remove the need to specify credentials on the command-line.

Connect to serveral hosts

...
PS C:\> $credRootUser = Get-Credential -Credential root

Windows PowerShell Credential Request
Enter your credentials.
Password for user root: *************


PS C:\> Connect-VIServer -Credential $credRootUser -Server hst0,host1,aHost23,hst45

Name                                    Port                       User
----                                    ----                       ----
hst0                                    443                        root
host1                                   443                        root
aHost23                                 443                        root
hst45                                   443                        root


PS C:\> Get-VM -server hst0

Name                 PowerState Num CPUs Memory (MB)
----                 ---------- -------- -----------
win7test             PoweredOff 1        1024


PS C:\> Get-VM | Format-Table Name, PowerState, NumCPU, MemoryMB, @{Label="HostName"; Expression={$_.Host.Name}}

Name                 PowerState Num CPUs Memory (MB) HostName
----                 ---------- -------- ----------- --------
win7test             PoweredOff 1        2048        hst0
dubuntu0             PoweredOn  1        768         host1
dubuntu8             PoweredOff 1        1024        host1
vMA4                 PoweredOff 1        512         aHost23
2k8test              PoweredOff 1        1024        hst45


PS C:\> Get-VM | Where-Object {$_.PowerState -eq "PoweredOff"} | Start-VM
...

Now connected to each host, one could perform whatever task(s) they desired. In this example, we got the VMs for one host, got the VMs for all hosts to which we were connected, and then started all powered-off VMs. Another example would be to gather VMNIC info as described in the "Find Busted VMNICs" post here at vNugglets.com. Yet another example would be, as Glenn at get-admin.com points out in his "Find vCenter without vCenter" post, finding the VMHost on which the vCenter VM resides in the case that vCenter services (or the VM) are not responding properly (and, so, one cannot connect to vCenter to determine this info).
This feature is most useful for managing hosts that are not managed via a vCenter instance. Once the given hosts are connected to a vCenter, admins can run their commands against said vCenter as per usual.