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Automate the migration from Virtual Standard Switch to vSphere Distributed Switch using PowerCLI 5.5

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I have been spending quite a bit of time in the lab lately working with some of our "future" software and one of the fun tasks I get to do is perform frequent rebuilds of my lab environment. Depending on the issues I encounter, I may even need to rebuild it on a daily basis and of course I have the majority of this automated so it is not as painful as it would be if I had to go through this manually.

The output of this build is a complete working vSphere environment that consists of several ESXi hosts connected to a vCenter Server with all the network and storage configured. On the networking front, the ESXi hosts were all running on a regular Virtual Standard Switch (VSS) and I needed to migrate them over to a Virtual Distributed Switch (VDS). In this particular environment, there is some Windows infrastructure and I thought about the different ways I could accomplish this and I remember hearing about some new VDS cmdlets that came out of PowerCLI 5.5. release.

Since I already had some scripts being kicked off on this Windows system, I thought I give the new PowerCLI cmdlets a try for VSS->VDS migration as I have heard good things about the new cmdlets. I performed my prototyping on a vSphere 5.5 environment, but I believe you might even be able to use this on older releases of vSphere.

Here is a list of the new VDS cmdlets that I used for the script:

Here are additional vSphere networking cmdlets that were required for script:

Even as a beginner of PowerCLI, I was able to quickly knock out a script that performed the migration from VSS to VDS and was able migrate ALL VMkernel interfaces and physical interfaces without any downtime. These new cmdlets definitely make it very easy for administrators to go from old Virtual Standard Switch over to the vSphere Distributed Switch.

Here is a overview of what my environment looks like which consists of three ESXi hosts with four physical NICs and three VMkernel interfaces.

The script below will create a brand new VDS and their associated Distributed Portgroups and attach a list of ESXi hosts which is configurable and performs the migration of VMkernel and physical interfaces. It does this by first moving two of the four physical NICs to the new VDS to ensure connectivity and then starts the migration of all VMkernel interfaces. Once that is complete, it will move the remainder physical NICs and then delete the Virtual Stand Switch portgroups.

Disclaimer: Please ensure you test this script in a development/test lab before using it in a production environment.

Connect-VIServer -Server vcenter55-1.primp-industries.com -User *protected email* -Pass vmware

# ESXi hosts to migrate from VSS->VDS
$vmhost_array = @("vesxi55-1.primp-industries.com", "vesxi55-2.primp-industries.com", "vesxi55-3.primp-industries.com")

# Create VDS
$vds_name = "VDS-01"
Write-Host "`nCreating new VDS" $vds_name
$vds = New-VDSwitch -Name $vds_name -Location (Get-Datacenter -Name "VSAN-Datacenter")

# Create DVPortgroup
Write-Host "Creating new Management DVPortgroup"
New-VDPortgroup -Name "Management Network" -Vds $vds | Out-Null
Write-Host "Creating new Storage DVPortgroup"
New-VDPortgroup -Name "Storage Network" -Vds $vds | Out-Null
Write-Host "Creating new vMotion DVPortgroup"
New-VDPortgroup -Name "vMotion Network" -Vds $vds | Out-Null
Write-Host "Creating new VM DVPortgroup`n"
New-VDPortgroup -Name "VM Network" -Vds $vds | Out-Null

foreach ($vmhost in $vmhost_array) {
# Add ESXi host to VDS
Write-Host "Adding" $vmhost "to" $vds_name
$vds | Add-VDSwitchVMHost -VMHost $vmhost | Out-Null

# Migrate pNIC to VDS (vmnic0/vmnic1)
Write-Host "Adding vmnic0/vmnic1 to" $vds_name
$vmhostNetworkAdapter = Get-VMHost $vmhost | Get-VMHostNetworkAdapter -Physical -Name vmnic0
$vds | Add-VDSwitchPhysicalNetworkAdapter -VMHostNetworkAdapter $vmhostNetworkAdapter -Confirm:$false
$vmhostNetworkAdapter = Get-VMHost $vmhost | Get-VMHostNetworkAdapter -Physical -Name vmnic1
$vds | Add-VDSwitchPhysicalNetworkAdapter -VMHostNetworkAdapter $vmhostNetworkAdapter -Confirm:$false

# Migrate VMkernel interfaces to VDS

# Management #
$mgmt_portgroup = "Management Network"
Write-Host "Migrating" $mgmt_portgroup "to" $vds_name
$dvportgroup = Get-VDPortgroup -name $mgmt_portgroup -VDSwitch $vds
$vmk = Get-VMHostNetworkAdapter -Name vmk0 -VMHost $vmhost
Set-VMHostNetworkAdapter -PortGroup $dvportgroup -VirtualNic $vmk -confirm:$false | Out-Null

# Storage #
$storage_portgroup = "Storage Network"
Write-Host "Migrating" $storage_portgroup "to" $vds_name
$dvportgroup = Get-VDPortgroup -name $storage_portgroup -VDSwitch $vds
$vmk = Get-VMHostNetworkAdapter -Name vmk1 -VMHost $vmhost
Set-VMHostNetworkAdapter -PortGroup $dvportgroup -VirtualNic $vmk -confirm:$false | Out-Null

# vMotion #
$vmotion_portgroup = "vMotion Network"
Write-Host "Migrating" $vmotion_portgroup "to" $vds_name
$dvportgroup = Get-VDPortgroup -name $vmotion_portgroup -VDSwitch $vds
$vmk = Get-VMHostNetworkAdapter -Name vmk2 -VMHost $vmhost
Set-VMHostNetworkAdapter -PortGroup $dvportgroup -VirtualNic $vmk -confirm:$false | Out-Null

# Migrate remainder pNIC to VDS (vmnic2/vmnic3)
Write-Host "Adding vmnic2/vmnic3 to" $vds_name
$vmhostNetworkAdapter = Get-VMHost $vmhost | Get-VMHostNetworkAdapter -Physical -Name vmnic2
$vds | Add-VDSwitchPhysicalNetworkAdapter -VMHostNetworkAdapter $vmhostNetworkAdapter -Confirm:$false
$vmhostNetworkAdapter = Get-VMHost $vmhost | Get-VMHostNetworkAdapter -Physical -Name vmnic3
$vds | Add-VDSwitchPhysicalNetworkAdapter -VMHostNetworkAdapter $vmhostNetworkAdapter -Confirm:$false

# Remove old vSwitch portgroups
$vswitch = Get-VirtualSwitch -VMHost $vmhost -Name vSwitch0

Write-Host "Removing vSwitch portgroup" $mgmt_portgroup
$mgmt_pg = Get-VirtualPortGroup -Name $mgmt_portgroup -VirtualSwitch $vswitch
Remove-VirtualPortGroup -VirtualPortGroup $mgmt_pg -confirm:$false

Write-Host "Removing vSwitch portgroup" $vmotion_portgroup
$vmotion_pg = Get-VirtualPortGroup -Name $vmotion_portgroup -VirtualSwitch $vswitch
Remove-VirtualPortGroup -VirtualPortGroup $vmotion_pg -confirm:$false

Write-Host "Removing vSwitch portgroup" $storage_portgroup
$storage_pg = Get-VirtualPortGroup -Name $storage_portgroup -VirtualSwitch $vswitch
Remove-VirtualPortGroup -VirtualPortGroup $storage_pg -confirm:$false
Write-Host "`n"
}

Disconnect-VIServer -Server $global:DefaultVIServers -Force -Confirm:$false

Here is a screenshot of running through the script:

If we now take a look at our enviornment, we can see all three ESXi hosts have been migrated over to the VDS.

UPDATE (11/4/13) -  Thanks to one of the PowerCLI engineers, it looks like there is a PowerCLI cmdlet that can be used to migrate from VDS->VSS. I will be sharing that script in another blog post for those that may want to perform the reverse.

One caveat that I hit during the development of this script is needing the ability to easily migrate between VSS->VDS and VDS->VSS. I was hoping it was simply reversing the set of operations and moving the VMkernel interfaces back to the Virtual Standard Switch but what I found for the Set-VMHostNetworkAdapter cmdlet is that it only accepts a Distributed Virtual Portgroup. This meant that I could only migrate to a VDS but not to a VSS. Though this will probably will fit the majority of customer use cases, for me this was a problem and means I will need to dig into the vSphere APIs to be able to seamlessly perform a VDS->VSS migration. Given that PowerCLI is an abstraction, we should be able to easily add this feature and I will be filing an FR with Engineering to see if we can get this added as I think it would be a useful feature to have.

What Are the Shadow of vmnic in ESXTOP?

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In ESXi 5.1, you might have noticed something new called Shadow of vmnic under the USED-BY column in the Network view of ESXTOP.

I initially heard about this from a few followers on twitter and I was curious myself since I could not find any documentation regarding this topic. It took a bit of digging but it turns out these shadow vmnics is actually related to the new VDS Health Check feature released in vSphere 5.1. A shadow port is created automatically for every uplink in your ESXi host and is used for transmitting and receiving health check related packets for each uplink. In ESXTOP, you can monitor the statistics for these shadow ports which can be used to debug/troubleshoot the network health check feature and this is why they are present.

One thing to note, these shadow ports are created regardless of whether or not your ESXi host is connected to a VDS or if you have the network health check features enabled. This is by design and there are four VMkernel modules that are responsible for the network health check feature:

  • vlanmtucheck
  • teamcheck
  • heartbeat
  • healthchk

Disclaimer: Do not modify or disable any of the above VMkernel modules else you can potentially disable network connectivity to your ESXi host (trust me, I know).

After some investigation and testing in my lab, I found that I could unload the above VMkernel modules and the shadow vmnics entries would no longer appear in ESXTOP. To do this, you will need an ESXi 5.1 host which is not running any virtual machines and you will need to run the following commands in this exact order (as there are module dependencies):

vmkload_mod -u vlanmtucheck
vmkload_mod -u teamcheck
vmkload_mod -u heartbeat
vmkload_mod -u healthchk

Once you have successfully unloaded all four VMkernel modules, if you open up ESXTOP, you should no longer see the shadow vmnics. To restore the shadow vmnics, you can either reboot (since the unload is not persistent) OR you can run the following commands in this exact order:

vmkload_mod heartbeat
vmkload_mod teamcheck
vmkload_mod vlanmtucheck

Note: By loading the heartbeat VMkernel module, it also loads the healthchk module.

Automatically Remediating SvMotion / VDS Issue Using vCenter Alarms

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UPDATE 07/13/2012 - vSphere 5.0 Update 1a has just been released which resolves this issue, please take a look here for more details for the patch as this script is no longer required.

In my previous article Identifying & Fixing Virtual Machines Affected By SvMotion / VDS Issue, I provided a script for users to easily identify the impacted VMs as well as a way to remediate them. Though the the issue was only temporarily fixed, as any of the remediated VMs can be re-impacted if they are Storage vMotion again (manually or automatically) by Storage DRS. This meant that users would to re-run these scripts every so often to ensure their environment is not affected by this problem.

I decided to look into a more automated and hands-off approach in which a Storage vMotion of a VM will automatically trigger the execution of the remedation script. I was able to successfully accomplish this by leveraging vCenter Alarms and running a script on the vCenter Server (Here's a cool thing I did with alarms awhile back) .

Disclaimer: This script is not officially supported by VMware, please test this in a development environment before using on production systems.

You can create the alarm at any level of the inventory hierarchy, but I would recommend placing it at least at the datacenter or cluster level. The alarm type will be for a VirtualMachine and it we use "monitor for specific events". For the trigger, we will need to use "VM migrated" and set the status to "Unset" which will not create an alarm icon when it is triggered.

You might wonder why we selected "VM migrated" versus "VM relocated" and this is actually due to the fact that a Storage vMotion starts out just like a vMotion and if you manually perform a vMotion or Storage vMotion, only this event type will be triggered. Due to this single event being triggered by two completely different operations, it has an interesting impact which we will discuss in a bit.

Next we need to create an action for this alarm which will be running a command, you will need to specify the full path to perl.exe (assuming you're using my script which is based on vSphere SDK for Perl and you will need to have vCLI installed on the vCenter Server) as well as the path to the alarm script which in this example is called alarm.pl. Also ensure you set the green->yellow action to execute once.

You will need to create the alarm.pl script on your vCenter Server and here is what it looks like:

#!/usr/bin/perl -w
# William Lam
# http://www.virtuallyghetto.com/

use strict;
use warnings;

my $scriptlocation = "C:\\querySvMotionVDSIssue.pl";
my $server = "localhost"
my $username = "VC-USERNAME";
my $password = "VC-PASSWORD";
my $debug = 0;

###########################
# DO NOT MODIFY PAST HERE #
###########################

my $start1 = "from";
my $start2 = "to";
my $end = ",";

# extract VMware env variables from alarm
my $eventstring = $ENV{'VMWARE_ALARM_EVENTDESCRIPTION'};
my $vmname = $ENV{'VMWARE_ALARM_EVENT_VM'};

my @sourcehost = $eventstring =~ /$start1 (.*?)$end/;
my @destinationhost = $eventstring =~ /$start2 (.*?)$end/;


# Output environmental variables to see what's up
if($debug) {
 open(FILE,">C:\\output.txt");
 foreach my $key (keys %ENV) {
  print FILE $key . "=" . $ENV{$key} . "\n";
 }
 close(FILE);
}

# if the source/destination host is the same, means we had a Storage vMotion instead of vMotion
# and we execute the remediation script on the VM
if($sourcehost[0] eq $destinationhost[0]) {
 `"$scriptlocation --server $server --username $username --password $password --vmname $vmname --fix true"`;
}

You will need to fill in the script location, in this example I have all scripts stored in C:\ and you will also need to populated the credentials which will be used to execute the script.

Earlier we mentioned that both a Storage vMotion and vMotion trigger the same event and because of that, we need to be able to identify when a Storage vMotion actually happens to run the script. The alarm.pl script above will be executed when the alarm is triggered and using the VMware specific environmental variables that is populated from the vCenter Alarm, we can extract from the event description to figure out whether it was a vMotion or Storage vMotion. Once we confirm it is a Storage vMotion, we then execute our remediation script which is from my previous article.

Note: Ensure you download the latest version of of the querySvMotionVDSIssue.pl from the previous article, as it has been updated to handle single remediation and targeted for this use case.

Now to verify that our alarm is functioning as expected, we can perform a manual Storage vMotion of a VM and we should see our alarm.pl execute and then after the Storage vMotion has completed, we should see some VM reconfiguration tasks which is from our remediation script.

So there you have it, you no longer have to worry about running the script every so often to ensure your VMs are not being impacted by the SvMotion / VDS problem. Again, I would like to stress though we are able to automate this remediation, this is not a real solution and VMware is actively working on a fix for this problem.

If you have any questions, feel free to leave a comment.