Red Hat Enterprise Linux 5.4 released

Today, it was released a next minor version of Red Hat's flagship Linux distribution RHEL 5.4. Here it is a brief summary of new features and updates:

• KVM hypervisor - Full support of Kernel-based Virtual Machine is included now. XEN support is included as well, but you can't use both XEN and KVM at the same time. Each hypervisor requires different kernel. You need to have 64b machine to run KVM. It supports RHEL 3/4/5 or Windows XP/2003/2008 as guests.
• KVM paravirtualized drivers - They are available for Windows XP/2003/2008 in package virtio-win.
• FUSE support - New version includes modules for Filesystem in Userspace (FUSE) and related utilities. Support for the XFS was added as well. It icnludes updates of CIFS and EXT4 filesystems.
• Infiniband drivers - It contains some portions of prepared Open Fabrics Enterprise Distribution (OFED) 1.4.1.

New release of RHEL contains many other updates and enhancements which aren't mentioned here. For more details read the RHEL 5.4 official release notes.

VMware or Citrix?

Citrix released their virtualization solution named XenServer (from version 5, article XenServer is free) for free but only the time will show if it was a right decision. At first glance, it seems like a marvelous thing but there are some facts which should be investigated first. Together with XenServer, it was released central management solution XenCenter.

Let's have a look at their rival VMware (vSphere 4). XenServer is fully comparable to VMware ESX or ESXi. But what about XenCenter management? It's something more than VMware vSphere client but not so valuable as VMware vCenter Management Server. Citrix XenCenter is not the right choice in case of comparison to vCenter. The right one is Citrix Essentials but this one is not for free already. The main differences between Citrix XenCenter and Essentials are:

• XenCenter is missing alerting capabilities like send me an email when "CPU usage is too high" or when some error condition like "virtual machine power on failure" appears
• XenCenter is missing high availability support
• XenCenter is not able to show you performance data older than one day for physical or virtual servers
  

Now, let's try to propose a simple high availability (HA) solution based on Citrix/VMware products and compare their prices. Let's suppose we have 2 (3) entry level servers where each have 2 CPUs with max 6 cores per CPU (6 CPUs total). The servers are connected to a shared disk storage. The CPU speed or memory capacity is not important now. And we require HA solution to protect our virtual machines from hardware failure. Follows the analysis:

- Citrix Essentials Enterprise (1 license = 1 server):

• XenServer - 2 licenses = 0$ (3 lic = 0$)
• Essentials Enterprise - 2 lic = 5500$ (3 lic = 8250$)
• Essentials Preffered Support (optional) - 1 lic = 1500$
  
• Total cost = 7000$ or 9750$ for 3 servers
  
• Total cost without support = 5500$ or 8250$ for 3 servers

- VMware vSphere 4 Standard Edition (1 lic = 1 CPU):

• vSphere 4 Standard - 4 licenses = 3180$ (6 lic = 4770$)
• vShpere 4 Standard 1y Gold Support - 4 lic = 1092$ (6 lic = 1638$)
• vCenter 4 Foundation - 1 lic = 1495$
• vCenter 4 1y Gold Support - 1 lic = 545$
• Total cost = 6312$ or 8448$ for 3 servers
• Support is mandatory

- VMware vSphere 4 Essentials Plus Bundle (1 lic = 1 CPU)

• Licenses for 3 hosts plus vCenter Server for Essentials plus 1y Gold Support = 3624$
• Total cost = 3624$ for 2 or 3 servers
  

The prices of proposed solutions are quite different. In my opinion, the most valued solution is based on new VMware product line vSphere 4 Essentials.

There are rumors that VMware is the most expensive solution. I don't think so if I check the numbers above. Citrix's solution not covered by support is cheaper then VMware's solution with support but only for 2 servers. If I would like to add third server I would have to pay another license in case of Citrix. In case of VMware, I have still one spare license so I will use it. At first glance, XenServer seems to be free of charge but the price of added value by Citrix Essentials doesn't scale as well as in case of VMware vSphere 4 Standard Edition or vSphere 4 Essentials Plus. And what is your opinion to the topic?

XenServer 5 license key

As you know, XenServer Enterprise Edition was realased for free. The license key for enterprise features and installation media are available from the download page. The new free XenServer will be released at March 25. The provided license provides high availability and StorageLink features from incoming Citrix Essentials for XenServer as well. The update to new version will be possible.

XenServer is free

It's unbelievable! Citrix decided to release their XEN based hypervisor and complete virtualization solution named XenServer for free a few hours ago (official announcement is here). The product was available in three editions until recently - Express, Standard, Enterprise and Platinum. The differences are outlined in the following table:

The Express edition was free of charge so far but it was missing some fundamental enterprise features like resource pools, live migration or central management console XenCenter. These features are paid. Or better, they were paid.

From now, we have only one edition of XenServer including features of enterprise edition. Everything is free and you can download it. Cool! You don't have to spend any money on virtual machines live migration, resource pools or central management stuff. What happens if we compare it with VMware ESXi? In my opinion, it seems the king might be dead. And the new king might be coming.

What do you think of it? What will be the answer from VMware? I think it is smart way how to show us that XEN based hypervisors are enterprise ready and how to spread it more. In connection with current economical situation they have the real chance to success.

Let me have final question. Who will need Microsoft Hyper-V now? If XenServer is free and because it is more mature and robust than Hyper-V what will be its new position? Today, the winner is Citrix. Tomorrow, the oponents might surprise us. But don't miss the opportunity today. Download XenServer and spread it!

Sun xVM Server 1.0 delayed?

Sun released their unified multiplatform management system for physical and virtual servers a few months ago but they still lacks of their own hypervisor called xVM. The release of xVM Server is planned during the first quarter of 2009 and it seems to be delayed now. Nevertheless, we can make some conclusion about the product now:

• it supports MS Windows, Linux and Solaris guests
  
• it is vmware compatible so you can directly use available vmware appliances
• it has built-in web-based management
• it supports virtual SMP (2 virtual CPUs)
• it supports live migration
• it supports resource pools
• it should be released with GPL3 licence at no cost (that's not a surprise as it is based on XEN)

I believe it will be released as soon as possible. Today, there are available source codes of xVM only. Binaries will be available with the oficial release of xVM.

Running NTPD inside XEN domU or not?

There is a question how to configure ntpd time synchronization daemon inside Linux domU. Is it better to guarantee the proper time of dom0 via ntpd and rely on automatic time synchronization between domU and dom0? Or is it preferable to make the domU clock independent of dom0?

I'm not sure with the right answer. I'm used to configuring ntpd daemon of each Linux system the same way. That means one configuration is suitable almost for each system. So I would rather use the second way to do it. Before it, you need to tell the system to make the domU clock independent with Linux sysctl interface:

echo "xen.independent_wallclock = 1" >> /etc/sysctl.conf
sysctl -p

After the above action, you can configure ntpd as you wish. For sure, check the set value with

sysctl xen.independent_wallclock

Red Hat prefers KVM to XEN! No doubt!

It's unbelievable but it's true! Red Hat in cooperation with AMD performs virtual machine live migration between different platforms - from Intel CPU to AMD cpu. You know, there are many difficulties to achieve it - like various extensions, instructions and so on.

So far, it was possible to migrate between processors of different family of one vendor only. Now, Red Hat can do it with RHEL and KVM which means Red Hat confirmed the replacement of XEN with KVM definitely. I wrote about it a few months ago here. The whole video story is published at youtube.

Virtualization leader

Will it be VMware? Or Microsoft? Or even Oracle? I think it is not right to say it will be this company or that. But it is clear that we can form some virtualization selection now which defines the leaders of actual virtualization market. I am pleased to use for it a screenshot provided by Gartner:

The most interesting part of the screenshot compares the number of deployed virtual machines by the specific virtualization technology. As we can see, VMware is still far away from the others. But have a look at VirtualIron or Oracle. Isn't it interesting?

As I don't know the source of the data used to produce the screenshot, I wouldn't like to deduce any great conclusions. I'm able only to say that VMware still rules and the others are coming. But one thing is clear - solutions based on XEN are strong and they have a great potential, haven't they?

In my opinion, It would be really cool to know the numbers of pure XEN installation - XEN in Linux distributions like SLES 10 or RHEL 5 and similar. Perhaps, we will be very surprised! The more detailed article which made me to write this short note was published at itmanagement.earthweb.com.

Red Hat prefers KVM to XEN?

Wow, the situation around Red Hat's attitude to the virtualization maze seems to be more clear now. I thought that Red Hat is going to support solutions based on XEN hypervisor. In 2007, they released RHEL 5.0 and it was their first distro with integration of XEN hypervisor. And I was looking forward to it.

But Red Hat considered the XEN to be immature as well. According to the article published at www.virtualization.info the main reason for such decision was acquisition of XenSource by Citrix and the collaboration between Microsoft and Novell and other vendors interested in XEN.

A few days ago, Red Hat unveiled their new virtualization strategy based on embedding the KVM hypervisor to their RHEL distro. The official announcement is published here and summarized some advantages of it.

I think it is interesting news but with many unanswered but important questions. Will they support both of hypervisors? Or are they going to support KVM only since now? What about their customers who already adopted the XEN in their environments? In my opinion, it will be quite difficult to make it mainstream. Let's wait and we will see...

Quickly - XEN hypervisor and full virtualization

An interesting article about XEN hypervisor and support of full virtualization (or HVM) was published in the last Red Hat Magazine release. It summarizes three useful commands how to find if your system supports it (run these commands from dom0):

• is your Intel CPU utilizing VT-x extension?
• grep -i vmx /proc/cpuinfo
• is your AMD CPU utilizing Secure Virtual machine (or SVM) extension?
• grep -i svm /proc/cpuinfo
• finally, is your XEN hypervisor capable of HVM?
• grep -i hvm /sys/hypervisor/properties/capabilities

The previous commands aren't RHEL specific only. They have to work on any XEN installation. By the way, the /sys/hypervisor/ directory contains many other useful information. If you would like to find out which processors support HVM take a look at XEN wiki pages.

New RHEL 5.2, new SLES 10 sp2

Wow, Red Hat company released today second update of their RHEL 5. Read the release notes and Red Hat NEWS. The most important enhancements are related to virtualization and Infiniband technology. RHEL 5.2 contains OFED in version 1.3 now. More about it in my previous article.

Further, Novell released the second service pack for their SLES 10. It is written about it at Novell NEWS. And what's new here? The second service pack is delivering XEN in version 3.2., updated Heartbeat2 or OCFS2 filesystem. More about enhancements is here. Official release notes are available as well.

So, let's go to download and test the products.