Wherein lies a potential problem: Given the fluidity of the environment, how do you protect against runaway usage?
"The right sizing of components in a private cloud is going to be a challenge for a lot of enterprises," Cribari says, "making sure you keep your finger on the pulse, knowing what's provisioned, and managing those resources."
It starts with basic controls.
"The good thing about a Web-based portal is you can manage who gets billed for that resource and even put in approvals," Cribari says. "So if Kirti orders a virtual machine and you don't want Kirti to order that machine because he doesn't have enough budget, you can, as his manager, say, No, that's not happening.' You can manage the environment so it doesn't get out of control."
With CITEIS Express, if you order a VM you are going to pay for it for 30 days, even if you only used it for a day. "When you get into Virtual Data Centers we provision for a quarter because it costs us to build and provision it," Cribari says. "So there are some guidelines and standard best practices that we're going to have to develop so our application owners understand."
To safeguard against resources getting stranded, Cisco does quarterly audits. "If someone says they need 32-gig of storage and they only use a fraction of that, we see that and take it back," Cribari says.
Anything under 30% utilization (40% on production systems) is considered underutilized and is reclaimed after checking with the owner —and put back in the resource pool. "Typically we see anywhere from 70% to 100% utilization," he says. "Anything between 40% to 70% is an ideal state. And if anything gets to more than 70% to 80%, that's where we say we need more resources."
Infrastructure capacity planning in this agile, virtual environment is done the same way as in traditional data centers, Cribari says. "If the engineers see that a virtual environment is hitting a threshold —70% in production, 60% in non-production —we get a team together to figure out what's the next logical upgrade? How much do we need? How do we design it and provision it before we need it?"
It just tends to be easier, says Kirti Thakkar, a Cisco Information Technology Engineer: "There's a UCS cluster here in Allen that can support 1,000-2,000 VMs, but probably right now it's running 200. So when it reaches 80% we can simply add another blade. We have a roadmap that keeps track of what's coming in the pipeline, so with the architecture and roadmap showing supply and demand, we can see what's needed in the next one to two quarters."
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