Speeding up Linux VMs with Hyper-V's Linux Integration Services

Upgrading Linux Integration Services

Since the ISO file ships with the necessary scripts to upgrade LIS on an existing installation, you don't have much to do. Just run the script relevant to your distribution, as follows:

  1. Mount the ISO file inside the Linux virtual machine.

2. As the root user, change to the directory relevant to your Linux distribution; for example,

    # cd /media/CDROM/RHEL6012
    # cd /media/CDROM/RHEL63

for RHEL/CentOS 6.0, 6.1, 6.2 (first line) or RHEL/CentOS 6.3 (second line).

  1. Run the following shell script to upgrade the Hyper-V-specific drivers:

        ./Upgrade.sh
  2. Finally, reboot the Linux virtual machine.

After reboot, use the lsmod or modinfo command to check the status of the LIS modules. (See "Uninstalling LIS" for information on how to remove LIS from within the Linux virtual machine.)

Uninstalling LIS

You can uninstall LIS from within the Linux virtual machine using the following set of commands. To begin, execute these commands from the base shell:

  rpm -qa | grep microsoft

Once executed, the command returns the version of the LIS installed:

  kmod-microsoft-hyper-v-3.4-1.20120727
  microsoft-hyper-v-3.4.20120727

Next, execute the command,

  rpm -e microsoft-hyper-v-<version string> kmod-microsoft-hyper-v-<version string>

which in this example would be:

rpm -e microsoft-hyper-v-3.4.20120727 kmod-microsoft-hyper-v-3.4-1.20120727

Conclusion

In this article, I described how to use LIS in Linux virtual machines running on Hyper-V Server. You learned how components provided by LIS improve the overall performance of Linux virtual machines, how to activate LIS on Linux distributions that ship with Hyper-V-integrated components, and how to install the new version of LIS on Linux. For a summary of known issues with running Linux in a virtual machine on Hyper-V, see the box titled "Known Issues and Limitations."

Known Issues and Limitations

Before you switch over all your Linux systems to run in Microsoft hosts, be aware that some issues and limitations still exist for running Linux guest operating systems on Hyper-V Server:

  • The ISO file is not mounted automatically. You must mount LIS ISO files using the mount command.
  • Formatting a VHDX file with an ext3 filesystem might fail. To work around this issue, either use an ext4 filesystem or create a VHDX file with a smaller block size, such as 1MB. Using the ext4 filesystem is recommended for production deployments of Linux on Hyper-V.
  • Windows Server 2012 includes support for 4KB sector size disks. However, the use of 4KB drives is limited to Linux kernels that support them. Red Hat Enterprise Linux (RHEL) did not include support for 4KB drives until version 6.0.
  • Virtual machines running Ubuntu 12.04 might not work correctly if they are configured with a legacy network adapter. A workaround is to configure Ubuntu 12.04 virtual machines with only Hyper-V-specific (or "synthetic") network adapters. Ubuntu 12.04 includes the Linux Integration Services drivers, but you must activate them as described in this article.
  • To ensure that all disks connected to the virtual machine are visible, all disks connected to a SCSI controller must start with location  .
  • If a disk was hot-removed from the system, the connected disks will not be rescanned until a new disk is added.
  • If you have virtual machines configured to use more than seven virtual processors, you should add numa=off to the GRUB boot.cfg file to work around a known issue in the Linux kernel. Similarly, If you have virtual machines configured to use more than 30GB RAM, you should add numa=off to the GRUB boot.cfg.
  • If Linux Integration Services is removed from a virtual machine configured to use more than one virtual processor, you should disable the irqbalance service to allow successful shutdown of the virtual machine.
  • Verifying the digital signature of the RPM packages under Red Hat Enterprise Linux (by executing the rpm -K command) returns a KEYS ARE NOT OK message.
  • You might see event log entries stating that a storage device or network driver is a different version from the server. You can safely ignore these messages.
  • SCVMM 2008 Service can crash with VMs running Linux Integration Components v3.1 for Hyper-V. The solution is to disable the KVP daemon on the Linux virtual machine, which will prevent the SCVMM service crash.

LIS Included

The following Linux distributions ship with LIS support. If you have one of these distros, you will still need to activate LIS before you can use it.

  • CentOS 5.9
  • CentOS 6.4
  • Red Hat Enterprise Linux 5.9
  • Red Hat Enterprise Linux 6.4
  • SUSE Linux Enterprise Server 11 with SP2 and SP3
  • Open SUSE 12.1
  • Ubuntu 12.04 and 12.10
  • Ubuntu 13.04 and 13.10

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