Version 5 of Red Hats Red Hat Enterprise Linux operating system hit the streets last month, complete with a truckload of updated open-source components and brand-new support for server virtualization-courtesy of the Xen hypervisor project.
eWEEK Labs tested RHEL 5 with a particular focus on its new virtualization features. While we think that Red Hat is off to a good start with its Xen implementation, companies in search of an out-of-the-box server virtualization solution shouldnt expect it from RHEL 5.
Compared with VMwares VI3 (VMware Infrastructure 3) and with the Xen-based Virtual Iron and XenEnterprise products weve reviewed, RHEL 5s tools for creating and managing guest machines are pretty Spartan, and our experiences installing and running Windows Server 2003 and RHEL 5 guests contained more troubleshooting and Googling than we would have liked.
However, we expect that any company looking for a general-purpose Linux operating system with solid support and lots of hardware and software certifications would be rather pleased with RHEL 5.
At sites where earlier RHEL versions are already in service, the upgrade should fit in particularly well. Red Hats subscription model has always meant that customers can upgrade between RHEL versions when they want, but the addition of virtualization support offers the alternative of running older versions of RHEL on a RHEL 5 box as virtual machines.
RHEL 5 supports x86 platforms, as well as Advanced Micro Devices Athlon 64 and Opteron; Intels EM64T (Extended Memory 64 Technology) and Itanium II; and IBMs Power, zSeries, and S/390 platforms.
eWEEK Labs tested the 64-bit version of RHEL 5 on an IBM x3655 server with two dual-core Opterons and 3.5GB of RAM; we ran the 32-bit version both in a VMware ESX Server VM and in a guest instance on our 64-bit RHEL test system.
With RHEL 5, Red Hat has shuffled its SKUs around a bit-what had previously been the entry-level ES server version is now just called Red Hat Enterprise Linux. This version is limited to two CPU sockets, and is priced, per year, at $349 for a basic support plan, $799 for a standard support plan and $1,299 for a premium support plan.
This version comes with an allowance for running up to four guest instances of RHEL. You can run more than that, as well as other operating systems, but only four get updates from, and may be managed through, RHN (Red Hat Network). We thought it was interesting how RHN recognized the difference between guests and hosts on its own and tracked our entitlements accordingly.
What had been the higher-end, AS version of RHEL is now called Red Hat Enterprise Linux Advanced Platform. This version lacks arbitrary hardware limitations and allows for an unlimited number of RHEL guest instances per host. RHELs Advanced Platform edition is priced, per year, at $1,499 with a standard support plan and $2,499 with a premium plan.
RHEL 5s most headline-grabbing feature is its integrated Xen virtualization support, which enables the product either to host Linux guest instances with Xen-aware kernels or, with the right hardware, to host arbitrary, unmodified guest operating systems, such as Windows.
Support for hosting applications in their own virtual compartments is becoming the norm for server operating systems. Sun Microsystems Solaris 10 has been doing it for more than two years, and Novells SLES (SUSE Linux Enterprise Server) 10 has been providing such support since last summer. Microsofts upcoming Windows Server "Longhorn" also will sport its own virtualization support.
The benefit of using virtualization within general-purpose operating systems is that these products typically offer broader hardware support than do bare-metal or appliance-type virtualization products. The downside is that operating systems, such as RHEL5, tend to offer virtualization services like erector-set pieces-virtualization-savvy OSes can deliver results similar to a product like ESX server, but theres some assembly required.
Once wed gotten our instances configured just so, they ran well, and hosting these guests atop a full-blown operating system meant access to all the facilities that RHEL 5 has to offer-for instance, a full range of storage options, including RHELs new iSCSI initiator. The configuration road, however, was certainly steeper than that for other products weve tested.
There are separate command-line and graphical interfaces for creating and manipulating guest instances running on RHEL 5. The products graphical virtualization manager starts you out with a dialog that offers to link you to a local Xen domain, a remote Xen host or to another sort of hypervisor. Only the first of these three options works-the other two are grayed out pending some future update.