Categoriearchief: VMware

vSphere Cluster Services (vCLS)

vmware_vSphere7_graphic_small1In vSphere 7.0 Update 1 (released in October 2020) a new feature was released called vSphere Cluster Services (vCLS). The purpose of vCLS is to ensure that cluster services, such as vSphere DRS and vSphere HA) are available to maintain the resources and health of the workload’s running the cluster. vCLS is independent of the vCenter Server availability.

vCLS uses agent virtual machines to maintain cluster services health. vCLS run in every cluster, even when cluster services like vSphere DRS and vSphere HA are not enabled.

The architecture of the vCLS control plane consists of max 3 virtual machines, also called system or agent VMs. The vCLS machines are placed on sperate hosts in a cluster. On a smaller environment (less than 3 host) the number of vCLS VMs will be equal to the number of hosts. SDDC (Software Defined Datacenter) admin’s do not need to maintain the life cycle of these vCLS VMs.

The architecture for the vSphere Cluster Services is displayed in this image.

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The vCLS VMs that form the cluster quorum state, are self correcting. This means that when the vCLS VMs are not available the vSphere Cluster Services will try to create, update or power-on the vCLS VMs automatically.

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There are three health states for the cluster services:

  • Healthy: The vSphere Cluster Services heath is green when at least one vCLS VM is running in the cluster. To maintain vCLS VM availability, there’s a cluster quorum of three vCLS VMs deployed.

  • Degraded: This is a transient state when at least one of the vCLS VMs is not available, but DRS maintains functionality. The cluster could also be in this state when either vCLS VMs are being re-deployed or getting powered-on after some impact to the running vCLS VMs.

  • Unhealthy: A vCLS unhealthy state happens when DRS loses it’s functionality due to the vCLS Control plane not being available.

The vCLS VMs are automatically places in there own folder within the cluster.

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The vCLS VMs are small, with minimum resources. If no shared storage is available the vCLS VMs are created on local storage. If a cluster is created before shared storage is configured on the ESXi host (for instance vSAN), it would be strongly recommended to move the vCLS VMs to the shared storage once it is created.

The vCLS VMs are running a customized Photon OS. In the image below you see the resources of a vCLS VM.

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The two GB virtual disk is thin provisioned. The vCLS VM has no NIC, it does not need one to communicate because vCLS leverages a VMCI/vSocket interface to communicate with the hypervisor.

The health of vCLS VMs, including power state, is managed by vSphere ESX Agent Manager (EAM). In case of power on failure of vCLS VMs, or if the first instance of DRS for a cluster is skipped due to lack of quorum of vCLS VMs, a banner appears in the cluster summary page along with a link to a Knowledge Base article to help troubleshoot the error state. Because vCLS VMs are treated as system VMs, you do not need to backup or snapshot these VMs. The health state of these VMs is managed by vCenter services.

Tags: VMware, vSphere, vCLS

Configure vMotion in vSphere environment

Download Recently I’ve expanded my lab environment with a second vSphere host. One of the advantages of having two vSphere hosts is that you can move machine from on vSphere host to the other. If you perform this move while the machine is powered down you don’t and need any additional configuration. However, if you want to move a running machine from one vSphere host to the other without losing connectivity to this VM, you need vMotion. First let me explain what vMotion is.

vMotion in vSphere allows a running virtual machine to move between two different vSphere hosts. During vMotion memory of the VM is sent from the running VM to the new VM (the instance on another host that will become the running VM after the vMotion). The content of memory is changing all the time. vSphere uses a system where the content is sent to the other VM and then it will check what data is changed and send that, each time smaller blocks. At the last moment it will very briefly ‘freeze’ the existing VM, transfer the last changes in the memory content and then start the new VM and remove the old one. This process will minimize the time during which the VM is suspended.

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Managing vSphere with PowerCLI (creating Tags)

DownloadVMware vSphere PowerCLI is a command line tool for automating vSphere and vCloud management.

VMware PowerCLI is a very powerful command-line tool that lets you automate close to all aspects of a vSphere management. This includes among others: network, storage, guest OS.

PowerCLI is distributed as PowerShell modules, and includes over 500 PowerShell cmdlets.

The first version of PowerShell was released in November 2006 for Windows XP, Windows Server 2003 and Windows Vista. We have come a long way since then. PowerShell is an important part of today’s IT landscape. By using PowerShell you can manage systems from different vendors in a unified way. I find myself using PowerShell almost every day in my work.

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How to remain in control of your Horizon environment

Ljmaegmnepbgjekghdfkgegbckolmcok-featuredIn this blog post I want to share a simple piece of advice that will help you in maintaining your VMware Horizon environment. Image management is an important part of managing your VMware Horizon environment. If you are using Instant Clones (this is the future proof way of delivering VMware Horizon VDI’s in your environment), during the image publishing phase (this is referred to as the Priming phase) VMware Horizon starts creating the following VM’s CP-Template, CP-Replica (both are turned off and there is one per datastore per Desktop pool) and a CP-Parent (this machine is turned on and there is one per ESX host per datastore per Desktop Pool).

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Update a VMware App Volumes AppStack


In this blog article I will describe the process of updating a VMware App Volumes AppStack.

VMware acquired CloudVolumes in August 2014 and released it with the name App Volumes in December 2014. App Volumes is free to owners of the Horizon View Enterprise bundle and can also be purchased as a standalone product.

VMware App Volumes has proven to be a very powerful product to deliver applications to both VMware Horizon as well as Citrix Virtual Apps & Desktops.

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Persistent VDI VMware Horizon


When it comes to virtual desktop infrastructure (VDI), administrators have a lot of choices. You may have wondered about the differences between VDI software vendors, (Citrix or VMware), remote display protocols (Blast, PCOIP, HDX) or all the different license forms out there.
Now for this blog lets tackle the first two questions, we will be using VMware Horizon and Blast for as remote display protocol.

VDI can be either persistent or non persistent. It al depends on the requirements of the workforce. Most office workers will be fine with a none persistent desktop. It delivers a constant user experience. It takes away many of the maintenance tasks physical devices require.

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Manage VMware AppVolumes via Ivanti Automation

OIP_thumbIn this blog article I will describe how you can automate assigning VMware AppVolumes to AD user groups by using PowerShell via Ivanti Automation. To accomplish this task I am using the API of App Volumes.

The Powershell function I am using I found online, and is created by by my former colleague Thomas Brown. I slightly altered the script to meet my needs to accomplish the task at hand.

VMware AppVolumes has proven to be a very powerful product to deliver application to both VMware Horizon as well as Citrix Virtual Apps & Desktops.

The relative parts of my setup are:

  • VMware AppVolumes 2.18.014U
  • Ivanti Automation 2020.1

If you like to know more about creating an AppStacks please read: More on AppStacks

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Updating your VMware Horizon Desktop Pool


This blog post will describe the steps to update your VMware Horizon Desktop pool with the latest snapshot of your master VM.

For this example we have updated our master VM with the latest Windows security updates, and we have updated the Ivanti Workspace Control agent to the latest version. There are a number of sources where you can find the best practices on how to create and seal the master image. An imported part of creating a master image is optimizing. A good way to go about this is using the VMware OS Optimizing Tool. The initiative, VDI Like a Pro, from LoginVSI provides a very good template to be used within the VMware OSOT for Windows 10.

Before we will start the update process we first need to consider how we will go about the update. Will we update the Desktop Pool immediately or will we schedule it outside of business hours. If we do run the update immediately we have to consider how we will affect the current sessions, do we want to force log off the current session or wait to update these VDI’s when the current sessions logoff.

To start the process for updating the VMware Horizon Desktop Pool we first need to open the properties of the Desktop Pool we want to upgrade.

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