How to Deploy Virtual Machines in RHEV Environment?

Introduction

Red Hat Enterprise Virtualization, or RHEV, is a virtualization platform developed by Red Hat Inc. that provides an open-source infrastructure for hosting virtualized workloads. It allows users to easily deploy virtual machines on top of a set of physical hosts, known as hypervisors. The RHEV environment consists of two main components: the management platform, which manages the entire infrastructure through a web-based interface called RHEV Manager; and the hypervisor hosts that run the virtual machines.

Preparing for Virtual Machine Deployment

System Requirements

Before deploying virtual machines in a RHEV environment, it is important to ensure that your system meets the necessary requirements. The minimum system requirements for RHEV Manager are as follows −

• 64-bit x86 architecture CPU with at least 2 physical cores

• 4GB of RAM (8GB recommended)

• 20GB of free disk space (50GB recommended)

• RHEL or CentOS 7.5 or later

In addition to these requirements, the hypervisor hosts must also meet certain criteria. Each host should have at least two network interface cards (NICs), one for management communications and another for VM network traffic. Each NIC should support gigabit Ethernet or faster speeds.

Installation of RHEV Manager and Hypervisor Hosts

To deploy virtual machines in a RHEV environment, you must first install the RHEV Manager and hypervisor hosts. The installation process involves several steps, including registering your systems with Red Hat, enabling repositories, and installing necessary packages. Once you have completed the installation process, you can begin configuring your hypervisor hosts by adding them to the RHEV Manager inventory.

Configuration of Data Storage

One of the most critical components of deploying virtual machines in a RHEV environment is configuring data storage. Before creating any virtual machines, it is important to define data domains that will be used to store VM images and disks. There are several types of storage domains that can be used in a RHEV environment, including local storage, NFS, iSCSI, and Fibre Channel.

Creating Virtual Machines in RHEV Environment

Understanding Virtual Machine Templates and Images

Virtual machine templates and images are essential components of virtualization. They provide a baseline for creating new virtual machines, helping to streamline the deployment process.

In RHEV, templates are preconfigured with an operating system and software stack, while images are created by capturing a running virtual machine. When creating new virtual machines in RHEV, these templates or images serve as a starting point for customization.

Creating a New Virtual Machine from a Template or Image

Creating a new virtual machine from a template or image is straightforward in RHEV. First, select the appropriate template or image and choose the option to create a new virtual machine. Next, provide general information about the VM such as name and description, along with selecting an operating system type.

Once this is done, you can adjust several configuration settings such as CPU allocation, memory allocation, storage allocation and networking options. During this stage of VM deployment on RHEV environment it's recommended to define clear naming conventions for easy identification of VMs in your infrastructure - especially when dealing with dozens or hundreds of VMs at once.

Configuring General Settings such as Name, Description and Operating System Type

As previously mentioned when creating a new virtual machine from an existing template or image you will need to specify general settings such as the name which should be unique for easy identification of your VM; description which is optional but helps explain what that particular instance does; operating system type which needs to be selected according to what your application requires (e.g., Windows/Linux).

Adjusting CPU Memory & Storage Allocations

Once you've specified basic information on General Settings tab it's time to expand further into the configuration options available including adjusting CPU memory & storage allocations which are critical factors in ensuring optimal performance of your VMs. You will need to decide on the amount of memory and CPU cores that each virtual machine will be allocated, as well as the amount of disk space. It's important to allocate resources carefully to ensure that there is no resource contention between virtual machines running on the same physical host.

Configuring Networking Options

Ensure that you configure networking options appropriately. You will need to specify network interface settings such as IP address, subnet mask, DNS servers, and gateway details for each virtual machine. You can also specify whether or not each virtual machine should have direct access to the Internet or not by configuring NAT (Network Address Translation) rules et al. Be sure to test your networking configuration before deploying your VMs into production!

Managing Virtual Machines in RHEV Environment

Starting and Stopping Virtual Machines

Once virtual machines have been deployed in RHEV environment, the next step is to manage them effectively. Starting and stopping virtual machines is an essential aspect of this task. Users can start or stop virtual machines in RHEV Manager through the web interface or command-line interface.

When starting a virtual machine, users can choose to start it from a stopped state or restore it from a suspended state. Similarly, when stopping a virtual machine, users can perform a graceful shutdown that sends a shutdown signal to the guest operating system or forceful shutdown that cuts off power immediately.

Monitoring Performance and Resource Utilization

To ensure that the virtual machines in the RHEV environment are running optimally, it is crucial to monitor their performance and resource utilization regularly. This includes tracking CPU usage, memory usage, disk I/O operations, network I/O operations, and other metrics related to performance and resource consumption.

RHEV Manager provides a dashboard view that displays real-time data on all hosts and their associated virtual machines. Additionally, users can drill down into individual VMs and see detailed information about their performance.

Viewing Usage Statistics

RHEV Manager has built-in tools for viewing usage statistics over time for both hosts and VMs in the environment. Users can generate graphs showing historical data for specific metrics such as CPU utilization over time or memory usage over time for each host or VM.

Setting Alerts for Thresholds

Users can set alerts based on specific thresholds of resource utilization using RHEV Manager's alerting system. This means that when certain metrics exceed predefined thresholds (e.g., high CPU usage), an alert will be triggered via email notification or SNMP trap.

Migrating VMs between Hosts

RHEV Manager provides a feature to migrate virtual machines between hosts in the environment. This is useful for load balancing workloads and for moving virtual machines to different hosts for maintenance or upgrades.

Users can initiate live migrations using RHEV Manager's web interface or command-line interface. Live migration allows VMs to be moved between hosts without any downtime, ensuring that workloads remain uninterrupted during the migration process.

Conclusion

Deploying virtual machines in RHEV environment is a critical process that requires proper planning and preparation. Before creating the virtual machines, one must ensure that the system requirements are met and that the RHEV Manager and Hypervisor Hosts are installed correctly. Additionally, configuring data storage is essential to ensure that there is enough space for the virtual machines.

Creating virtual machines involves using templates or images to set up general settings such as name, description, and operating system type. Adjusting CPU, memory, and storage allocations is also necessary to match the needs of each virtual machine.