The virtual data center, building the cloud, pt2

This article is the second in my series about construction of our data center virtual cloud based on Xen Cloud Platform. The first part covered the design engineering of the cloud, the next part will cover cloud operations, and the final part will examine where we go for the future.

Installing XCP on each cloud host system is extremely easy. Download the ISO, pop it in the drive, boot, and in less than 15 minutes, you have a complete operational cloud host. There are a few gotchas to avoid in the process, however. SInce XCP is a brand new system, documentation is sparse, command and control is a limited machine console and a command line interface, and there were some hardware compatibility issues.

On the hardware side, XCP had trouble with the Broadcom 5704 (aka Tigon 3) Ethernet adapters built in to the servers. This was easily worked around by using the built in ports for access to the NFS storage server and adding Intel Pro 1000s for XCP traffic. Testing with production hardware is a must before deployment.

The cloud hosts are completely manageable with the built in command line interface. XCPs cli is designed in a way that makes it ridiculously easy to integrate into scripts. I used the cli just long enough to verify the proper operating steps, then combined them into shell scripts that drastically reduce the effort to manage the cloud hosts and VMs and reduce the time involved. Turning up a CentOS VM from a local installation server only takes a couple of minutes of attention and 20 minutes to complete, unattended.

The only tuning required for the cloud was the NFS storage server. The NFS storage is shared between the cloud hosts, allowing VMs to be moved easily between cloud hosts. Performance of the NFS server makes a major difference in the responsiveness of the VMs. In the case of VMs used as virtual workstations, the VM is replacing a physical machine, so the VM is measured against a high standard. Tune, tune, and tune again.

In a nutshell, this is the construction of a virtual data center cloud. Stay tuned for the next segment on cloud operations!

Vern, SwiftWater Telecom


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