Mixing Windows and Linux: How Do You Manage Choice?
Microsoft’s Windows operating systems account for the biggest share of server spending in the data center, but Windows is by no means the only show in town: Linux’s market share in particular is growing strongly. It’s growing because in Red Hat Enterprise Linux (RHEL) and SUSE Linux Enterprise Server (SLES) there are at least two distros that are seen as enterprise ready and suitable for the big time, and also because it’s cheap, manageable, good for virtualization and it runs the software that many people want to use. There are many more reasons as well.
What that means is that there will likely be many more “significantly mixed” data center environments (meaning environments running a significant number of servers using both Windows and Linux) in the future than there have been in the past. Windows-only data centers, or ones which only run the odd Linux server or two, will become increasingly rare.
But how do you manage mixed environments? Running different management systems for each platform is inefficient and would drive many administrators nuts. Besides, the whole point of a management system is to enable the monitoring and controlling of every relevant system in an organization from a single console. Not from two or three.
More On Mixed Environments
Virtualization makes things even more complicated: How do you manage Windows and Linux servers which may be running on physical servers or as virtual machines running on Microsoft’s Hyper-V, VMware’s ESX, or the Xen hypervisor?
Competing Management Choices
If you are coming from a Windows environment and moving toward a mixed environment by implementing Linux, then you may already be using Microsoft’s System Center management system. System Center’s Operations Manager 2007 module now includes (in beta) a Cross Platform Extensions pack with support for:
- HP-UX 11iv3 (PA-RISC and IA64)
- Sun Solaris 10 (SPARC and x86)
- IBM AIX 5L V5.3, Technology Level 6, SP5 (PowerPC) and, significantly,
- Red Hat Enterprise Linux 5 Server
- Novell SUSE Linux Enterprise Server 10 SP1
Virtual machines are managed from System Center using the Virtual Machine Manager 2008 (VMM) module, which also supports virtual machines running on VMware’s ESX server as well as Hyper-V. And VMM also integrates with VMware’s VI3 software so that it can be used to carry out VI3 management operations. For example, it is possible, from within VMM, to initiate a VMotion operation which moves a running VMware virtual machine from one physical host to another without stopping the virtual machine. (Microsoft currently has no equivalent to VMotion —its Quick Migration involves stopping the virtual machine for some seconds as it is moved to a new host.)
By way of competition Novell offers its Zenworks management system, which includes desktop and mobile device management as well as management services for the following server platforms:
- NetWare(R) 5.1, NetWare 6 and NetWare 6.5
- Novell Open Enterprise Server
- Windows 2000 Server and Windows Server 2003
- SUSE(R) Linux Enterprise Server 8 and 9
- Red Hat Advanced Server 2.1 and Red Hat Enterprise Server 2.1
- Red Hat Enterprise Linux AS 3 and 4 and Red Hat Enterprise Linux ES 3 and 4
- Solaris 9
Microsoft’s Favorite Linux Distribution
Both of these management systems allow the management of Windows and both SLES and RHEL, but Microsoft appears to favor the former over the latter. Demonstrating this, the company signed a set of agreements with Novell in November 2006 to work towards better interoperability between Windows and SLES in four areas:
- systems management
- directory integration and identity
- office document formats
The deal, which runs at least until 2012, has been treated with a great deal of suspicion by many people, partly because it can easily be construed as a way for Microsoft to get a “pet” Linux distro which it can control and use to get a better understanding of Linux and customers’ reasons for wanting to use it for its own advantage. The deal includes an agreement for Microsoft to refrain from taking legal action against Novell’s customers for using Linux (which Microsoft claims infringes various of its patents,) and also involves Microsoft making payments to Novell (and therefore indirectly subsidizing SLES.) One way this is achieved is by buying support coupons from Novell, which Microsoft then sells on to its customers at a discount.
One of the most notable results of the agreement is that SLES 10 is now the only Linux distro jointly supported by the two companies as a guest operating system virtualized on Hyper-V, and Windows Server 2008 is jointly supported when run as a paravirtualized guest on SLES using the Xen hypervisor included with the distro.
“The interop agreement is alive and working …”
Despite the suspicion, many organizations view the interoperability agreement as a positive step and are happy to take advantage of the benefits it offers. “The interop agreement is alive and working, and the fact that it is a long term agreement is good news,” says Nick Leake, Director of Operations and Infrastructure at ITV, a UK-based commercial broadcasting company which runs about 200 Windows servers and 100 SLES servers.
ITV has taken advantage of the agreement between Microsoft and Novell to buy discounted support coupons for SLES, but Leake says this did not influence his decision to implement SLES in the first place. “We made the decision four years ago, before the Novell - Microsoft interop agreement,” he says. “We carried out an evaluation process before making the conscious decision to go with SUSE. We chose not to go with Red Hat because they don’t have the same engagement level with customers as SUSE, and when the Microsoft Novell deal came along [it] simply confirmed that we had made the right decision.”
Leake also says that the ability to manage SLES from within Microsoft’s System Center is very important—although ITV opted to use Novell’s Zenworks to manage both platforms. He says support for the operating systems in each other’s virtual environments is also beneficial.
As Linux becomes increasingly accepted it’s likely that mixed data center environments will become more and more common. What’s more, the lines between different platforms will become more blurred as virtualization—including VMware’s vision of servers that can be moved within an internal cloud and out to external cloud service providers - and better interoperability make it possible to treat Windows and Linux servers—both physical and virtual—simply as computing resources which are provisioned and managed with the same tools in the same way.