RHEV-H 7.2 : Getting Started

RHEV-H or Red Hat Enterprise Virtualisation Hypervisor is Red Hat’s KVM based hypervisor supported by Red Hat. For the sake of testing and getting to know KVM in general and Red Hat’s hypervisor in particular, I installed it as a VM on a Nutanix Cluster running ESXi 6.0. So read on if you would like to know the recommended steps in order to run RHEV-H as a VM on ESXi/Nutanix successfully.

RHEV-H is a minimal operating system based on Red Hat Enterprise Linux. It is distributed as an ISO file and is a closed system. Filesystem access and root access are limited. Yum is disabled.

RHEL-based hypervisor is a thick host provides full access to the OS. Additional packages can be installed on the host in addition to KVM hypervisor.

To install RHEV-H on ESXi 6.0, please make sure you have the following configurations on ESXi:

  • New Virtual Machine creation wizard select Custom configuration for the VM
  • Guest OS as “Other” and version as “Other (64-bit)”
  • Select the NIC adapter as “VMXNET 3”
  • The SCSI controller should be “LSI Logic SAS”
  • Enable hardware assisted virtualization to the guest OS via vCenter Web Client.
    • Login to vCenter Web Client –> Edit Settings for the VM –> Virtual Hardware –> Expand CPU ….
    • Scroll to “Hardware Virtualization” –> check “Expose hardware assisted virtualization to the guest OS”
    • NOTE: If this is not checked then virtulisation capabilities of the underlying hardware will not be exposed to RHEV by ESXi.

The rest of the options selected are as per Red Hat’s recommended hardware requirements for running RHEV-H

Get Started with Installation ….

  • Red Hat provides 60 day evaluation of RHEV-H and a 30-day evaluation for RHEL subscriptions. Both these will be needed for RHEV-H and RHEV-M (Management Virtual machince hosting the redhat web console via which you will be able to manage your Red Hat virtualisation Environment).
  • Make sure to download the following iso files from RHN after you have registered for the Evaluation. (for this demo we will use the following:)
    • rhev-hypervisor 7.2 ISO
    • RHEL 6.7 x86_64 ISO
    • RHEV Guest Tools 3.6 ISO

Proceed with Installation:

  • Mount the rhev-hypervisor 7.2 ISO as CD-Drive on the VM and connect on power on. This enables the VM to boot from the ISO and proceed with the installation.

I am not going to cover all the options during installation here as most of them are self explanatory and upto your discretion. However, I will mention some of the options and what they mean, which should help you configure them to suit your environment.

  • Storage Volumes: For this lab I have attached a virtual HDD of 100GB to the VM on which I plan to deploy RHEV-H. During installation, Storage Volumes section should display the disk size and ask you for sizes of the following partitions:
    • “UEFI / Bios” and “Root&RootBackup” partition sizes will be set by default and greyed out – 256 MB & 4300MB respectively. You cannot modify them.
    • The size of the partitions that you can customize are SWAP / Config / Logging / Data
  • SWAP Partition: The partition is used by the system when physical memory (RAM) is full and the system needs more memory resources. The inactive pages in the RAM are moved to the swap space and the free pages of memory in RAM are used for pages which are more frequently used. Note: The swap space should not be considered a replacement for additional RAM. Its size is determined by the system memory workload rather than the size of system memory. If you need to calculate the size of the swap partition then use the following formula:
Recommended swap + (RAM * over-commit) = swap partition size

Over-commit ration is generally 0.5 and minimum size for the swap partition is 8MB. It cannot be set to zero.

  • Config Partition: Stores the configuration files for the hypervisor. Minimum size 8MB
  • Logging Partition: Stores all logs for the hypervisor. Recommended size 2048MB
  • Data Partition: Stores kdumps (Kernel Dump files), Hypervisor ISO files for hypervisor upgrades. kdump files are usually the size of host system RAM. Recommended size 1.5x of RAM plus an additional 512MB. Minimum size 256MB. The remaining disk space is allocated to data partition.
    • NOTE: If you are hosting RHEV-M locally on the system then the data partition should be large enough to accomodate 60GB of RHEV-M. So allocate space for data partition accordingly.

The rest of the installation is setting up passwords for the admin account and then installing the hypervisor. At the end of a successful installation, a reboot will be required.

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