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Cloud Fallacies and the Real World (Gillian Law, KTN)
2011-02-27 11:26:56
Cloud computing still stirs up quite a lot of antagonism in some people – there are regular „it‟ll never work‟ pieces in the press expounding the unseen dangers of letting your data out of the confines of your own data centre.
Along with this, writers regularly quote the „Fallacies of Distributed Computing/Cloud‟, a list written seventeen years ago by L. Peter Deutsch, then working at Sun Microsystems, along with his colleague James Gosling.
It‟s worth a look at these „fallacies‟, because there‟s an element of truth in the fact that, yes, these are issue that need to be considered. But are we all being led astray by the chimera that is cloud?
1. The network is reliable
2. Latency is zero
3. Bandwidth is infinite
4. The network is secure
5. Topology doesn‟t change
6. There is one administrator
7. Transport cost is zero
8. The network is homogeneous
http://blogs.sun.com/jag/resource/Fallacies.html
Starting at the top – is the network reliable? And if not (because of course it‟s not completely), is the lack of reliability a problem?
“One hundred percent reliability is a fallacy,” says Johnny Paterson, business development manager at SymetriQ. “But any cloud provider is more resilient than just about any corporate network – we provide fully redundant, resilient networks because it‟s our core business. If we have an outage it‟s catastrophic. When it‟s core to your business you just invest more in it,” he says.
“There‟s not a single measure of reliability that you can measure, anyway,” says Alex Bligh, CEO of Flexiant. “You might get the occasional break of a second or two, but for most applications that isn‟t the end of the world – the network heals itself, and for most applications it‟s sufficiently reliable.”
The way applications are being engineered is changing, too, says Bligh. “You can‟t expect everything to be working all the time and never fail – applications today are built to cope with unreliability and carry on.”
Network reliability can be the Achilles Heel of cloud, admits Digital Systems KTN Director Ian Osborne, “but you just need to know whether it‟s good enough for your business needs, and robust against the risk of disruption from DDOS attacks and the like.”
Latency, from „fallacy‟ number two, is never zero, it‟s true, says Osborne, but that‟s true of anything web based, he says. “If you want very low latency, you have to pay for it – and unless you‟re working on a trading system or other specialist area, it‟s not necessarily an issue.”
“If the data‟s in a sensible place in the first place, latency‟s not really a problem,” says Bligh.
“If the data and the compute power are both remote, then you‟re fine. And cloud providers have put a lot of effort into reducing latency, to the point where it‟s better than most in-house set ups. If you think about it, most big enterprises are global and have compute power in different countries – until we work out how to beat the speed of light the issue‟s always going to be there, there‟ll always be a 70mllisecond round trip between New York and the UK. What matters is how you deal with that.”
Paterson says that customer perception of latency can be difficult to handle. “Our datacentre is in Slough, and one reason for that is exactly this perception of latency as a problem. And yet the reality is, people use Salesforce.com without a thought, and they‟re connecting to the US ! We use salesforce.com ourselves, and yes, we do see some latency but it‟s not anything to worry about,” he says.
Bandwidth can certainly be a concern for cloud providers – often it‟s at the client‟s end that things need to be improved.
“It‟s not an issue for us, at Symetriq – we have multiple high bandwidth connections,” says Paterson. “But it can be at the customer‟s end, and it can mean adding extra lines – but it is possible to get 50 Megabits to your home these days, it‟s easy to fix!”
One hiccup is that bandwidth is generally asymmetric, with very little upload bandwidth compared to what‟s available for download, says Osborne. “The myth of Digital Britain was that we can all have two megabits at home, but that‟s very difficult to achieve in practice, whether in heavily built up urban areas or remote locations.
That brings us to security – the bugbear of any cloud salesperson.
But “it‟s probably less than an issue than it was even a year ago,” says Paterson. “The cloud providers have done a good job of explaining it, and people are starting to realise it‟s probably more secure than the customers‟ own sites. Even physically, at some sites just about anyone can stroll in – whereas we have government-level security. And in terms of network access most companies have VPN access these days to let people connect from home, and they can see the cloud‟s no different.”
And as Bligh says, “the network IS insecure, and that‟s no bad thing. You can‟t build impregnable gates but you can build applications capable of surviving attacks. We‟ve been doing that since the 1990s, anyone who builds an internet application without the right technology needs to reconsider what they‟re doing. The risks are there, but they‟re generally possible to control, so long as you start with the premise that things are insecure.”
Topology – this one cause some confusion, as it‟s not clear what‟s meant, but “one benefit of cloud is that you can change the topology yourself – it does change but it‟s within your control and it should be transparent,” Bligh says.
Storage is the area where topology is likely to change the most, says Paterson, “and there‟s a lot of people addressing the issue, looking at speed and scalability.”
Administration and staffing issues always come up when there‟s talk of cloud. What does it mean for the careers of people working in IT today, and how do you manage people who are running a vast network, like a cloud provider‟s datacentre?
“The provision of any service today requires managing many services and providers, both inside and outside an organisation,” Osborne says. “How do you manage those service providers – there‟s a whole new set of skills needed, it‟s true. But you just need to train and find the right people to do it,” he says.
Bligh agrees. “People are used to having complex security capabilities, multiple teams managing different aspects of IT, so the cloud isn‟t very different, really. Back in 92/93, phone relay networks became popular and people worried then about the risks of handing over control to a supplier - we‟re just in the same situation here.”
Transport costs might not be zero but they‟re not a massive concern for most, says Paterson. “We sometimes have to get the customer to add more bandwidth at their end, but at the moment we bundle that into the cost of the service.
“You do need to keep adding capacity, but people will be prepared to pay for what they want to do , if it‟s important enough to them,” says Osborne.
And obviously, some situations just aren‟t suited to remote processes, says Bligh. “If you‟re running a video animation suite, for instance, you‟re moving enormous amounts of data and you have to keep it in-house. But for the rest of us, who don‟t get to watch comics all day, the cost isn‟t big.”
And to the final point: homogeneity. “Heterogeneity actually protects against failure, by making it hard to bring systems down,” says Osborne. And standards are in place that allow heterogeneous systems to work smoothly together anyway, says Paterson.
Overall, all of the cloud fallacies reflect some truth, but they don‟t add up to a reason to baulk at cloud technologies.
“Like the Facebook status – „it‟s complicated‟,” says Bligh. “I‟m not a cloud evangelist – it‟s not a solution to everything, clearly some applications suit it and others are less well suited. I think lists like this make it more like a religious argument when instead you have to look at what‟s right for the customer and for the application. Cloud suffers from a surfeit of religion... But still, lists and myths about cloud at least illustrate the questions that are worth asking.”
This article is produced by Digital Systems. Its publication does not imply any endorsement by Digital Systems of the products or services referenced within it. Any use of this article independent of the Digital Systems’ Web site must include the author's byline plus a link to the original material on the Web site.
https://ktn.innovateuk.org/c/document_library/get_file?uuid=afbed104-c405-4d21-becf-e6033fb37683&groupId=31318
Gillian Law
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