In this chapter, we will cover the following topics:
Right-sizing virtual machines
Enabling CPU Hot Add and Memory Hot Plug
Using paravirtualized VM hardware
Creating virtual machine templates
Upgrading and installing VMware Tools
Upgrading VM virtual hardware
Using vApps to organize virtualized applications
Using VM affinity and anti-affinity rules
Using a VM to host affinity and anti-affinity rules
Converting physical servers with vCenter Converter Standalone
Virtual machine (VM) design is just as important as physical hardware design and should be part of the physical design process. Correctly designing and configuring virtual machines with proper resource allocation will help increase consolidation in the virtual environment and ensure that a virtual machine has access to the resources that it requires in order to run the workloads efficiently.
A few questions that should be answered as part of the virtual machine design are as follows:
What resources will be assigned to individual virtual machines?
What virtual hardware will be allocated to virtual machines?
How will new virtual machines be deployed?
How will multiple virtual machines supporting an application be grouped based on dependencies?
How will virtual machines be placed on host resources in order to ensure the efficient use of resources and availability?
How will physical servers be converted to virtual machines?
This chapter will cover right-sizing virtual machines to ensure...
Right-sizing a virtual machine means allocating the correct amount of CPU, memory, and storage resources required to support a virtual machine's workload. Optimal performance of the virtual machine and efficient use of the underlying hardware are both obtained through right-sizing virtual machine resources.
In a physical server environment, it is difficult to add resources. Because of this, physical servers are often configured with more resources than actually required in order to ensure that there are sufficient resources available if the need for resources increases. Typically, physical servers only use a small percentage of the resources available to them; this means that a great deal of resources are constantly kept idle or wasted. Adding resources to a physical server also typically requires the server to be powered off and, possibly, even removed from the rack, which takes even more time and impacts the production.
In a virtual environment, it becomes much...
Adding CPU and memory resources to a virtual machine is a simple process. The process of adding resources to a virtual machine is to power down the virtual machine, increase the number of vCPUs or the amount of memory, and power on the virtual machine again.
In vSphere 4.0, two new features, CPU Hot Add and Memory Hot Plug, were introduced to allow virtual machine vCPUs and the virtual machine memory to be increased without requiring the virtual machine to be powered off. CPU Hot Add and Memory Hot Plug must first be enabled on the virtual machine, which requires it to be powered off. Once enabled, however, CPU and memory resources may be added dynamically; powering off the virtual machine is not necessary.
Perform the following steps to enable vCPU Hot Add and Memory Hot Plug for virtual machines:
Check the VMware Guest OS Compatibility Guide, which can be found at http://partnerweb.vmware.com/comp_guide2/pdf/VMware_GOS_Compatibility_Guide...
Paravirtualization provides a direct communication path between the guest OS within the virtual machine and the ESXi hypervisor. Paravirtualized virtual hardware and the corresponding drivers installed with VMware Tools are optimized to provide improved performance and efficiency. This hardware includes the VMXNET network adapter and the PVSCSI storage adapter.
Adding paravirtualized hardware adapters to a virtual machine is done using the following steps:
Access the Guest OS compatibility section of the VMware HCL at http://www.vmware.com/go/hcl in order to determine the guest OS support for paravirtual adapters. A screenshot of the Guest OS compatibility HCL with the Networking and Storage adapters in highlighted red boxes is shown in the following screenshot:
To install the paravirtualized network adapter, edit the virtual machines' Virtual Hardware, add New Network adapter, and select VMXNET3 for...
Virtual machines can be deployed quickly from prebuilt templates. Virtual machine templates are configured with minimum CPU, memory, and storage resources. The guest operating system and any prerequisite applications are installed in the template. Instead of taking hours (or even days in some cases) to install the operating system and prepare the server, once a template has been created, a new virtual machine can be deployed within minutes. Virtual machine templates not only allow for quick deployment, but they also help maintain consistency across virtual machines deployed in the environment.
The following steps are required in order to create a virtual machine template:
Create a virtual machine; configure the vCPU, memory, and storage resources; install the guest operating system; install the required applications; and apply any application or operating system updates or patches.
The virtual machine can be cloned to a template using the Clone...
VMware Tools enhances performance and improves the management of virtual machines by loading optimized drivers for virtual hardware and installing utilities to access virtual machine configurations and metrics. VMware Tools is not required, but for optimal virtual machine performance, it should be installed on all virtual machines in the environment. The status of VMware Tools is displayed on the virtual machines Summary page, as shown in the following screenshot:
The drivers for the optimized paravirtual hardware, such as the VMXNET3 adapter and the PVSCSI adapter, are included in VMware Tools, and VMware Tools must be installed before the hardware is available for use with in the guest. VMware Tools should be installed and kept up to date on every guest operating system.
The virtual machine hardware version or virtual machine compatibility specifies the version of virtual machine hardware presented to the virtual machines and the ESXi versions that the virtual machine is then compatible to run on. Updating the virtual machine hardware exposes new features available to virtual machines—for example, the ability to provision vmdks up to 62 TB—and ensures that the virtual hardware is optimized to the version of ESXi.
To upgrade the virtual hardware of a virtual machine, perform the following steps:
Install or update VMware Tools in the virtual machine.
Edit the settings of a virtual machine and access the Virtual Hardware tab.
If a virtual hardware upgrade is available, the Upgrade option will be available. Select Schedule VM Compatibility Upgrade, as shown in the following screenshot:
Set the compatibility level the virtual hardware should be upgraded to, as shown here:
Shut down and power on the virtual machine to upgrade...
vApps can be used to group individual virtual machines with interdependencies into a single application. A common use case for this would be a multitier web application that requires a web server frontend, an application server, and a supporting database server. The application can then be managed as a single inventory object.
The following steps can to be performed to use vApps to organize virtual machine workloads:
Create a new vApp by launching the New vApp wizard, as shown in the following screenshot:
The method to create the vApp (either creating a new vApp or cloning an existing vApp), the vApp name, the folder location, and the resource allocation settings are configured in the New vApp wizard, as shown in the following screenshot:
Once the vApp has been created, you can add virtual machines to the new vApp by dragging them into the vApp. The following screenshot shows a vApp containing the Prod1 and Prod2 virtual machines...
When virtual machines are powered on in a DRS cluster, vCenter determines where the virtual machines should be placed in order to balance resource usage across the cluster. The DRS scheduler runs periodically to migrate virtual machines using vMotion in order to maintain a balance of resource usage across the cluster. Affinity or anti-affinity rules can be used to control where VMs are placed within a cluster. Affinity rules keep VMs on the same physical host, reducing the load on the physical network by keeping traffic between them from leaving the host. Anti-affinity rules keep VMs separated on different physical hosts, ensuring higher availability.
One case of an affinity rule would be to keep all of the virtual machines supporting an application on the same host. This would ensure that network communications between the virtual machines supporting the application do not traverse the physical network.
An example use case of an anti-affinity rule...
Virtual Machine to Hosts rules can be created to keep virtual machines on or off specific hosts or groups of hosts. These types of DRS rules are useful in order to keep management virtual machines, such as vCenter Server, on specific hosts to make these virtual machines easier to locate in the event of a failure. This also allows virtual machines to be separated across different hosts in a rack or blade chassis in order to ensure that the loss of a rack or chassis does not impact all virtual machines, for example, to split members of a Microsoft SQL always on availability group across chassis.
The following process is used to create Virtual Machine to Hosts affinity or anti-affinity rules:
There are two methods to virtualize workloads running on physical servers. The workloads can be migrated into the virtual environment by creating new virtual machines, loading a guest operating system, installing applications, and migrating the application data to the new virtual machines; or, physical servers can directly be converted to virtual machines using VMware vCenter Converter Standalone.
The following steps are required to use VMware vCenter Converter Standalone:
Download VMware Converter from http://www.vmware.com/web/vmware/downloads.
VMware Converter can be installed either as a local installation or as a client-server installation. More information on installing VMware Converter is available in the VMware vCenter Converter Standalone guide, which can be found at http://www.vmware.com/support/pubs/converter_pubs.html.
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