Jun
4
2019

Migrating virtual machines using PowerCLI

In my current role as a VMware architect, I architected a greenfield VMware vSphere 6.5 environment.
The ‘old’ environment, who I architected 4 year ago, is VMware vSphere 5.5. As the old environment was never updated, the time and risk of upgrading this environment was too high. That’s why, we decided to go for a greenfield installation.
As the new environment was accepted by the customer system administrators, we had to migrate 700 virtual machines to the new environment.
The old environment was using NFS datastores, as the new environment is using hyperconverged.
As the old environment was vSphere 5.5 U1, we weren’t able to vMotion virtual machines to the new cluster, using Cross vCenter vMotion.

To make the migration as painless as possible, I create a PowerCLI script to do the hard work for us.

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Apr
9
2019

Reboot or shut down vSAN node: Take your time!

While working at a customer’s site, I notice that a system administrator wanted to reboot a vSAN node. The time it took to shutdown the node was too long (30+ min) for the system administrator, so he used iDRAC to hard reset the host.
I asked him, why he just didn’t wait until the host was completely shut down?
He answered, that according to him, this didn’t matter, because ESXi was installed on a SD card. Before he hard reset the host, he makes sure the host is in maintenance mode, so no virtual machine is running on that host and vSAN data is guaranteed.
The system administrator noted that this SD card is only used during boot time.
After ESXi has booted, you can pull out the SD card and ESXi will continue to operate as normal. So in his opinion, he could easily hard reset ESXi, as long he ensured that no virtual machines a running on that host.

This statement is partially true, but before I dive into this statement, first a little background information.
[expand title=”Read more…”]
During ESXi boot, a RAMdisk is created. This RAMdisk is among other things used to store the VMkernel, modules and the scratch partition. The scratch partition is used for storing log files.
To ensure that log files are available after a reboot, during shutdown, these log files are copied to persistent storage (in this case a SD-card). During boot, the same log files are copied from persistent storage (SD-card) to the scratch partition on the RAMdisk.
So, the statement that the SD card isn’t used after the VMkernel is up and running is not completely true. During a shutdown of ESXi, the SD card is also used!

In this case, the customer was using VMware vSAN. vSAN generates vSAN trace log files that are stored on in the scratch partition.
Although the size of the log files is limited to 180 MB by default. For most SD cards, this can take up to 30 minutes to be copied.
As you can see in the screenshot below, vmhba32 is 100% used but is only copying data by 0.02 MB per Sec with an average latency of 66.25 ms.

So, what are your options to avoid long start-up of shutdown times?
1. Limit the size of your vSAN trace files. Do mind, in case of troubleshooting, you can miss some important information!
2. Store your log files on a syslog server or a central VMFS datastore.
3. Don’t use SD card for ESXi using VMware vSAN. A SATADOM is not that expensive and much faster than a SD card. Of course, you can also use a local (SSD) disk.

Final note: When shutting down your VMware vSAN node, take your time![/expand]

Oct
31
2018

Catch me at VMworld Europe

VMworld Europe is just a few day away, and I’m looking forward to a week of fun stuff! 

One of the main reason why I go to VMworld, is to meet new people. I love a good (tech) conversation. It inspires me, in my day to day work. Not only as a IT person, but also as a private person. So, if you want to meetup, this is where you can find me.

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Oct
10
2018

ESXi and Nutanix post configuration using PowerCLI

For years I’ve been using kickstart for the installation and configuration of VMware ESXi. Who doesn’t know William Lam kickstart blogs?
Using kickstart, I can do a fully unattended installation and configuration of ESXi.

But, when using an HCI solution like Nutanix, host are pre-installed (foundation) with VMware ESXi, and the Nutanix CVM runs (as a VM) on the hypervisor. So you don’t need to install ESXi separately. 
If you want to use one script to configure VMware ESXi and the Nutanix CVM. Which includes configuring options like changing default passwords or adding a ESXi host to a VMware Distributed vSwitch, kickstart using esxcli and bash command, isn’t flexible enough anymore.

After a little digging around in different options, I decided to use PowerShell. This enables me to create an configuration script, where I can configure 98% of all the setting I want. This script can run on your laptop or on a management server.

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Sep
3
2018

VMworld 2018 US: My thoughts

It’s has been almost a week since VMworld 2018 US. And I have to say, what a week!

I’ve spoken to so many people. Old friend made some new friend, and spoke to a lot of vendors on the Solution Exchange.

In my opinion, this VMworld was great! Not because of all the new exciting things that were announced. 

But more because most of the announcement where about product upgrades and feature improvements.

I like the fact, VMware is taking his time, to make his product more mature (not that they aren’t mature already, but you get my point).

Let me recap the most important thing, that struck me.

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