InfoWorld review: Cisco UCS wows
Cisco's Unified Computing System is a more manageable, more scalable, and essentially superior blade server system, despite 1.0 wartsFollow @pvenezia
You can also use the virtual media facilities present in the remote KVM feature. This is somewhat old hat by now, but you can select an ISO image from your local system to present to the blade as a connected CD or DVD, and boot from that to install the OS. Here's where another funny thing happens: Generally speaking, there are no drivers to install. Windows Server 2008, RHEL 5.3 and later, and VMware ESX 3.5 U4 already have all the required UCS drivers present in the default install. You might think that Cisco's been planning this for some time. You might also think that Cisco has some significant pull with various OS vendors. You might be right.
Bouncing around the room
So you have your blades built with Windows Server 2008, VMware ESX, RHEL 5.3, or whatever. Each of them can play on however many VLANs you've defined, bind to whatever SAN LUNs you've presented, and are basically fat, dumb, and happy. So what happens when a blade goes down?
There isn't a truly defined high-availability aspect to UCS, which is somewhat disappointing. However, if you assign the server instance to a pool of blades, and it boots from a SAN LUN, then the failure of the blade running that instance will result in the instance being booted from another, identical blade in that pool. This process takes several minutes, due to the fact that UCS needs to prepare the target blade with all the specifics of the service profile, then reboot, but it does provide basic HA capabilities. It would be nice to see some form of "real" HA defined on UCS, though this poor-man's HA is functional.
Another significant facet of UCS is the concept of organizations. Cisco's management framework for UCS is not unlike that of LDAP in that it leverages the concepts of inheritance. Thus, it's possible to create organizations that have their own policies, pools, and service profiles, while child organizations can draw from the parent organization pools and so forth, inheriting policies and pools from above. This makes management simpler by allowing you to create global pools and policies that can become catch-alls, while getting more granular with those that are applied to the specific organization.
Further, administration can be delegated along organizational lines. Using another facility dubbed Locales, administrative users can be granted specific rights to specific management duties to specific organizations, with those rights flowing downhill to sub-organizations.
The tale of the scale
As with all IT infrastructure initiatives, scalability is key. Surprisingly, this isn't really an issue with UCS. Each UCS 6120XP FI can handle 144 blades with dual LAN uplinks, and the soon-to-be-released 6140s will handle up to 304 blades in the same fashion. This controller-to-blade ratio is off the charts, allowing UCS installations to scale dramatically, while requiring only the relatively cheap chassis and blades rather than the pricier FIs.
There are also significant provisions for multitenancy. For instance, perhaps you have separate working groups or even customers that need dedicated physical separation from not only each other, but through completely separate LANs. This can be achieved through the use of Pin Groups, which essentially pin specific physical interfaces to groups of servers. These can be applied on either LAN or SAN connections, so you can pin specific SANs to specific service profiles -- not specific blades.
This permits situations such as the following: Say four blades are deployed from a single service profile created for a specific department with its own LAN and SAN. These service profiles would be pinned to specific uplink ports run to that LAN and SAN. Should a blade fail, the service profile that was assigned to that blade will be brought up on another blade -- perhaps within another chassis -- yet that server instance will still maintain the physical separation as part of the pin group. This is a huge benefit for service providers and enterprises that have physically disparate network and storage segments. It places the UCS solution in the middle of any number of different network topologies while retaining physical separation, and it happens automatically.