All Things Xen

General ramblings regarding Citrix XenServer & its open source counter part.

Running Scientific Linux Guest VMs on XenServer

Running Scientific Linux Guest VMs on XenServer

What is Scientific Linux?

In short, Scientific Linux is an customized RedHat/CentOS Linux distribution provided by CERN and Fermilab: popular in educational institutions as well as laboratory environments.  More can be read about Scientific Linux here: https://www.scientificlinux.org/

From my own long-term testing - before XenServer 6.2 and our pre-release/Alpha - Creedence - I have ran both Scientific Linux 5 and Scientific Linux 6 without issues.  This article's scope is to show how one can install Scientific Linux and, more specifically, ensure the XenTools Guest Additions for Linux are installed as these do not require any form of "Xen-ified" kernel.

XenServer and Creedence

The following are my own recommendations to run Scientific Linux in XenServer:

  1. I recommend using XenServer 6.1 through any of the Alpha releases due to improvements with XenTools
  2. I recommend using Scientific Linux 5 or Scientific Linux 6
  3. The XenServer VM Template one will need to use will either be of CentOS 5 or CentOS 6: 32 or 64 bit depends on the release of Scientific Linux you will be using

One will also require a URL as to install Scientific Linux from their repository, found at http://ftp.scientificlinux.org/linux/scientific/

The following are URLs I recommend for use during the Guest Installation process (discussed later):

Scientific Linux 5 or 6 Guest VM Installation

With XenCenter, the process of installing Scientific Linux 5.x or Scientific Linux 6 uses the same principles.  You need to create a new VM, select the appropriate CentOS template, and define the VM parameters for disk, RAM, and networking:

1.  In XenCenter, select "New VM":

2.  When prompted for the new VM Template, select the appropriate CentOS-based template (5 or 6, 32 or 64 bit):

3.  Follow the wizard to add processors, disc, and networking information

4.  From the console, follow the steps as to install Scientific Linux 5 or 6 based on your preferences.

5.  After rebooting, login as root and execute the following command within the Guest VM:

yum update

6.  Once yum has applied any updates, reboot the Scientific Linux 5 or 6 Guest VM by executing the following within the Guest VM:

reboot

7.  With the Guest VM back up, login as root and mount the xs-tools.iso within XenCenter:

7.  From the command line, execute the following commands to mount xs-tools.iso within the Guest VM as well as to run the install.sh utility:

cd ~
mkdir tools
mount /dev/xvdd tools/
cd tools/Linux/
./install.sh

8.  With Scientific Linux 5 you will be prompted to install the XenTools Guest Additions - select yes and when complete, reboot the VM:

reboot

9.  With Scientific Linux 6 you will notice the following output:

Fatal Error: Failed to determine Linux distribution and version.

10.  This is not a Fatal Error, but an error induced because the distro build and revision are not presented as expected.  This means that you will manually need to install the XenTools Guest Additions by executing the following commands and rebooting:

rpm -ivh xe-guest-utilities-xenstore-<version number here.x86_64.rpm
rpm -ivh xe-guest-utilities-<version number here>.x86_64.rpm
reboot

Finally after the last reboot (post guest addition install) one will notice from XenCenter that the network address, stats, and so forth are available (including the ability to migrate the VM):

 

I hope this article helps any of you out there and feedback is always welcomed!

--jkbs

@xenfomation

 

In-memory read caching for XenServer
Off to OSCON ....

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Comments 3

Terry Wang on Monday, 28 July 2014 03:56

Running PV on HVM (also called PVHVM sometimes) is just fine. For modern Linux distros with Linux 3.0+ kernel (it'll unplug the QEMU emulated disk and network devices and switch to Xen PCI platform PV drivers for disk and network), it outperforms pure PV guests.

Personally I think sooner or later XenServer commercial version will add PVHVM mode support for Linux guests. I'd like to see an official article or blog post on this ;-D

1
Running PV on HVM (also called PVHVM sometimes) is just fine. For modern Linux distros with Linux 3.0+ kernel (it'll unplug the QEMU emulated disk and network devices and switch to Xen PCI platform PV drivers for disk and network), it outperforms pure PV guests. Personally I think sooner or later XenServer commercial version will add PVHVM mode support for Linux guests. I'd like to see an official article or blog post on this ;-D
JK Benedict on Saturday, 27 September 2014 09:03

Stay tuned! I have more to offer for Creedence... especially in lieu of Mr. Mackey's request from the following article @ http://xenserver.org/blog/entry/creedence-final-beta-available.html

Beta 3 hit the press before I could finalize the steps I have used from 6.x into Creedence. The major point with my work is that for previous versions -- of course there is not support for this and I am not part of the Engineering, QA, and overall team that puts these operating systems to the extremes.

What I am is a contributor and fan, so what is posted here on behalf of each blogger, I hope you can leverage! Keep your comments coming in because right now - in Beta 3 - Ubuntu as a PV/HVM is screaming fast on my pathetic home lab machines!

--jkbs | @xenfomation

0
Stay tuned! I have more to offer for Creedence... especially in lieu of Mr. Mackey's request from the following article @ http://xenserver.org/blog/entry/creedence-final-beta-available.html Beta 3 hit the press before I could finalize the steps I have used from 6.x into Creedence. The major point with my work is that for previous versions -- of course there is not support for this and I am not part of the Engineering, QA, and overall team that puts these operating systems to the extremes. What I am is a contributor and fan, so what is posted here on behalf of each blogger, I hope you can leverage! Keep your comments coming in because right now - in Beta 3 - Ubuntu as a PV/HVM is [b]screaming[/b] fast on my pathetic home lab machines! --jkbs | @xenfomation
Ian Yates on Wednesday, 30 July 2014 10:24

Hi, I'm new to this community but independently worked out a (pretty much identical) install routine for ScientificLinux on Xen so can confirm that this works.

I'm wondering whether anyone done any performance/benchmark tests for running ScientificLinux in a cluster both virtualised and un-virtualised? I'm curious to see what the virtualisation overhead is. The reason I'm considering this is I have some old single-threaded code which I want to run in parallel on different parts of a dataset and might make sense to virtualise a host and create a number of VMs to allow the code to "fan out" on a single host...

1
Hi, I'm new to this community but independently worked out a (pretty much identical) install routine for ScientificLinux on Xen so can confirm that this works. I'm wondering whether anyone done any performance/benchmark tests for running ScientificLinux in a cluster both virtualised and un-virtualised? I'm curious to see what the virtualisation overhead is. The reason I'm considering this is I have some old single-threaded code which I want to run in parallel on different parts of a dataset and might make sense to virtualise a host and create a number of VMs to allow the code to "fan out" on a single host...

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