Advanced VM and Resource Management

Once the setup of the vSphere environment has been completed, the deployment of VMs is the final step to fire up your virtual infrastructure. When the hosts and vCenter Server are in place, they provide physical resources to the VMs that physically reside on the storage device shared among the environment.

The chapter will drive you into the structure of VMs and their configuration to better understand how they work and what options to configure to obtain best performance. The use of templates is a key point in the management of VMs since it simplifies the management of the environment, allowing easier creation and faster deployment of new VMs. Relying on a ready-to-run machine, admins just need to do a minor setup. As compared to physical machines, VMs deployed from a template don't need to be installed from scratch and this allows you...

VM components

A VM behaves in exactly the same way a physical computer does, but it's actually a software computer that runs an OS and applications supported by the host's provided resources. A VM supports all the functionalities and presents the same devices as a physical machine, but it's easier to manage and more secure.

Typically, a VM can be configured to run on ESXi hosts, datacenters, clusters, or resource pools and includes three main core components:

• Virtual and hardware resources
• OS
• VMware Tools

Virtual hardware

When you create a VM, the ESXi host presents the hardware as a specific set of resources to the VM. The hardware type provided by the configuration wizard has been selected by VMware to ensure...

Deploying VMs

The creation of VMs in vSphere 6.5 is a core task and different methods are available for deployment. The most suitable deployment method to use depends on the goal of the VM, the configuration, and the type of infrastructure the VM will run on.

You can create a VM with the following methods:

• Creating a VM from scratch: If you need a VM with a specific configuration, OS, or application and it's not already present in your environment.
• Using templates: If a VM has the requirements you need and it's often deployed, the use of a template (a master copy of a VM) is the option to consider. This option requires a minor setup after the deployment and allows you to save time.
• Cloning: If similar VMs are deployed in your environment, the cloning option requires less time than creating and configuring a VM from scratch.
• Virtual appliance: A VM with an OS and applications...

Managing VMs

When VMs have been deployed in your infrastructure, you can start the administration using the available tools and features offered by vSphere Client. Several actions can be performed on VMs to keep a clean inventory and a healthy infrastructure. Let's have a look at some common procedures an administrator performs on a regular basis.

Adding or registering an existing VM

VM can be created or deployed using the different methods shown previously. In some circumstances, you might need to put in your production environment a pre-created VM from another source. You may wonder how do I deploy this virtual machine?. The procedure is not complicated at all; let's see.

First, using vSphere Client, you need to...

Resource management

The number of VMs that can run on ESXi is not infinite and the optimization of the resources ensures best performance. As compared to the physical world, where each server is often equipped with more resources than it actually needs, in a virtualized environment, you can allocate suitable resources to a VM based on its role and function.

An FTP server, for example, doesn't need to be equipped with a dual processor and 6 GB of RAM because the resources will be underutilized. Allocating a suitable amount of RAM and a correct number of CPUs, you can obtain best performance, saving resources for other VMs. Understanding how to manage and reallocate resources is then a key point to avoid overcommitment of resources (more demand than available capacity) that can compromise the entire infrastructure functionality.

Hosts and clusters (a group of hosts where...

VM migration

In vSphere 6.5, VMs can be moved from one host or storage to another using hot or cold migration. Wherever possible, hot migration is the preferred option to use to avoid service disruption because it performs a live migration of the VMs:

• Hot migration: A powered-on VM can be moved to a different host or datastore without service disruption using the vMotion or Storage vMotion features.
• Cold migration: This is the migration of a powered-off or suspended VM. You can move associated disks from one datastore to another and VM are not required to be on shared storage. A cold migration can be performed manually or by scheduling a task.

The migration of a VM is performed by following this procedure:

1. From vSphere Client, log in to vCenter Server, right-click the VM to move, and click the Migrate... option.
2. In the Migrate window, select the migration type to perform...

Converting VMs

There are some situations where you might need to convert a physical machine to a VM or import a VM from a third party to take advantage of the scalability, reliability, security, and features provided by the vSphere platform, released from hardware constraints. If you have old physical machines or physical machines running specific applications, OS, and configurations that require time for a fresh reinstallation, and service downtime for a long period is not tolerated, conversion to a VM might solve the problem.

You may also be requested to import in vSphere VMs created for different virtual platforms, and to run those VMs in a VMware environment, they must be converted in a supported format.

To migrate the OS, applications, and data to the virtualization platform, the VMware vCenter Converter tool (available to download from the VMware website at the URL https...

Summary

In this chapter, we talked about VMs, that is, a software computer composed by a file structure that specifies the configuration (.vmx) and the virtual disk used to store data (.vmdk) and core components, such as virtual and hardware resources, OS, and VMware Tools. A VM can be deployed using different methods (created from scratch, clone, templates, and OVF/OVA) depending on the features requested. The use of a Content Library can simplify the deployment process.

We have seen that, once installed, a VM can be added or removed from the inventory, keeping the VM data. Snapshots can be used to take a specific point in time of a VM in order to quickly revert at any time in case of need. A typical use case is the patching process; before applying a new patch, taking a VM snapshot allows you to quickly revert in case of problems. Snapshots can be created and deleted, but sometimes...