New in VMware vSphere 4 is the ability to streamline the configuration of new ESX hosts. As part of my ongoing testing of the vSphere 4 platform, I put the new feature through its paces in the lab.
Host profiles help to solve the finicky problem of ensuring uniformity among the groups of physical ESX host systems that support the virtual machine environment. The host profile feature is a good addition to vSphere 4, but the need for it may be lessened by the abilities of the new distributed switch that was also added in this overhaul of VMware's flagship data center virtualization platform.
That said, the host profiles feature handles much more than just network configuration, touching memory and security settings, too. And, during my tests using the host profiles feature, it was relatively simple to reapply a profile to a system to ensure that its configuration hadn't deviated. Further, the host profile is an integral part of the vSphere 4 package; there is no extra cost for taking advantage of the profiling features.
I used host profiles in my VMware vSphere test center running on Hewlett-Packard and Sun servers. I'm currently using an HP DL380 G6 and an HP DL360 G6, along with a SunFire x4170. All three servers are loaded with Intel Xeon 5500 series processors and 12 GB of RAM.
For this test, I basically optimized the ESX configuration on my DL380, then created a host profile based on that configuration and applied the profile to the vSphere ESX installation running on my DL360 and SunFire x4170 systems. The host profile acts on the VMware ESX software configuration and does not require exactly matching hardware. However, I would be cautious about applying a host profile to a physical system that wasn't at least within the same processor family.
Creating the ESX configuration can be as simple or as complex as you wish. I installed a fresh copy of ESX 4 on my reference server and set up memory reservation, storage, networking, time/date and firewall details. Once the details were set, the actual process of creating a profile took just seconds.
Once created, a host profile must be attached to a cluster or host before it can be applied to a system. The procedure for attaching a profile is straightforward--you just right-click on the host in the vCenter management console.
Hosts must be in maintenance mode before a host profile can be applied. A system message in the management console clearly indicates what changes are to be applied to the host, and then the process is carried out.
In my test case, I took the host profile I'd created on the HP system and applied it to a ESX installation on the Sun system. The profile applied correctly, and the ESX system on the Sun server functioned as expected. With no further configuration effort on my part (beyond specifying IP address assignments that I chose to make when I created the profile), the Sun system was integrated with my iSCSI data store. I was then able to migrate virtual machines from one host to another with no loss of connectivity or application functionality.
Host profiles make new host configuration a snap. However, an experienced VMware engineer will still need to create and vet the configurations that will be the basis for new host systems. Once this is done, junior administrators can be given the relatively simple task of deploying the profile.
Host systems can easily be checked for compliance with current host profile settings. During tests, I removed the iSCSI network virtual switch from the ESX installation on my Sun system. When I manually checked for compliance, the missing virtual switch was highlighted. Reapplying the profile solved the configuration problem.
In the future, I'd like to see a little more automation of host profiles. Manual checks such as those I performed to check for for compliance could be easily scheduled as a recurring task in off-peak times. Aside from this rather small point, the new host profiles feature is a nice advance in ESX configuration administration.
Technical Director Cameron Sturdevant can be reached at firstname.lastname@example.org.