What is the Cloud and how does it work?
I was asked recently by someone, who doesn’t work in the technology industry, what exactly is the Cloud? Cloud based applications and Cloud hosting are terms which most people are familiar with and probably use regularly, even if they don’t realise it. In this blog post I aim to provide an explanation of what the Cloud is and how it works.
The term ‘Cloud Computing’ has been attributed to the Google CEO, Eric Schmidt in 2006 so it has been around for a while.
Where is The Cloud?
The concept of Cloud Computing means that applications which are hosted in The Cloud can be accessed from anywhere with Internet connectivity. People using Cloud based applications will usually have no idea where the application is physically located and in reality, it may be served from multiple geographic locations for resilience purposes.
Cloud based applications and hosting services are physically delivered from many Data centres around the world. Data centres are generally highly secure facilities which usually try and keep a fairly low profile in the physical environment in which they exist. Data centres provide a carefully managed temperature controlled environment for typically hundreds or thousands of physical servers and related communications equipment.
Physical access to Data centres is carefully managed to ensure that only authorised personnel are allowed to enter.
Pulling back the curtain
In recent years Cloud based services have become very popular with organisations and individuals. Consumers of Cloud based services do not typically need to have any technical staff on board in order to use them. This is one of the reasons why Cloud based applications have risen in popularity so quickly. Most Cloud based services are provided either free of charge or for a monthly subscription. Organisations who use Cloud based services do not need to set up or host any systems themselves. A fast and reliable Internet connection is all that is needed to be able to use the services.
When a user initially connects to a Cloud based service, the request will be received by their Internet Service Provider (ISP) and the Domain Name System (DNS) will translate the name into an IP address. The IP address is effectively a pointer to a physical location where the Cloud service is located. Large Cloud based providers will host their services across multiple Data centres so your request will be directed to the location which is either the closest or least congested.
A typical Data Centre, where Cloud services are hosted, is a secure and environmentally controlled environment which is optimised to run many servers. The provision of a reliable power supply is very important; therefore, most Data centres have multiple power feeds from the power grid and also Uninterruptible Power Supplies (UPS) on site and backup generators. Fast and resilient Internet connectivity is of course essential and most Data centres have Internet feeds (think pipes) from multiple providers.
Data centres are classified in Tiers based on the level of resilience they have. Tier 1 Data Centres have the least resilience and will have some single points of failure. Tier 4 Data Centres offer the highest level of fault tolerance and redundancy.
Incoming requests from users into a Data centre will initially be received by an edge router which will direct the traffic to the correct server or servers via a series of data switches. Some Data Centres will have border protection devices at the perimeter to help identify and stop malicious requests.
The service request will be processed by a physical server or array of servers and the result will make the return journey back to the user.
This all has to happen within a small number of milliseconds, otherwise the user of the Cloud service will quickly experience a slow or sluggish service.
Where is my data located?
Organisations based in the UK and Europe are now subject to the General Data Protection Regulation (GDPR), therefore it is important to know where your data is physically located whilst it is at rest. Some Cloud service providers now allow their users to choose in which physical location their data is stored. For security reasons Cloud service providers will not disclose the exact physical location of their Data Centres, only that the data is stored in a specific area such as the UK or Europe.
What is a private Cloud?
A private Cloud uses all of the same technologies and components which I have detailed so far. The only real difference is that the resources are ‘reserved’ for a particular organisation or group, therefore making it private. An organisation could set up its own private cloud by installing their own physical equipment and locating it at a secure Data Centre. Users would then be able to access the services which are hosted on the private cloud by first verifying their identity prior to gaining access.
Resilience and redundancy of Cloud based applications
Most users of Cloud based services never think about the physical infrastructure which has to be in place to deliver them, until of course something goes wrong. Larger providers of Cloud based services will typically host their system across multiple Data centres and have the ability to divert traffic in the event of a problem. Sometimes however even the larger providers suffer downtime when failed updates get replicated to a number of Data centres, which can be the cause of fairly major outages.
Although Cloud based applications have an element of redundancy and resiliency built in, it is worth considering what would happen if their systems were unavailable and if it is possible for you to have a copy of your data which you can store in an encrypted secure way outside of their Cloud.
The Oxford Web Applications Cloud
At Oxford Web Applications we have been providing secure and resilient hosting solutions for our clients for over 20 years. We have set up our own private cloud which is fully managed and supported by our own team. Our systems are physically located in the UK and geographically spread across two independent Data Centres. We aim to provide 100% uptime for all the applications we manage on behalf of our clients.