At this moment, the concept of cloud computing appeared - the consumption of IT services from the "cloud", i.e. from some external pool of resources, not caring how or where these resources come from. Just as we do not care about the infrastructure of the water utility pumping stations. At this point, the other side of the concept was also worked out - namely, the concept of IT services and how to manage them within ITIL / ITSM.
A number of definitions of clouds (cloud computing) have been developed, but they should not be treated as the ultimate truth - this is just a way to formalize the way utility computing is provided.
- "Cloud computing is a distributed data processing technology in which computer resources and power are provided to the user as an Internet service" Wikipedia
- “Cloud computing is a model for providing convenient network access to a shared pool of configurable computing resources (such as networks, servers, storage, applications and services) on demand, which can be quickly provisioned and delivered with minimal management effort or minimal intervention. service provider »NIST
- “Cloud computing is a paradigm for providing network access to a scalable and flexible pool of distributed physical or virtual resources, delivered in a self-service mode and administered on demand” ISO / IEC 17788: 2014. Information technology - Cloud computing - Overview and vocabulary.
There are three main types of clouds according to NIST:
- IaaS - Infrastructure as a Service - Infrastructure as a Service
- PaaS - Platform as a Service - Platform as a Service
- SaaS - Software as a Service Software as a Service
For a very simplistic understanding of the difference, let's look at the Pizza-as-a-Service model:
NIST defines the following necessary features of an IT service to be considered cloud-based.
- (broad network access) – , . – 220 (), , , .
- (measured service) – . – , , , .
- (on demand self service) – , . , . ( ) .
- (rapid elasticity) – / ( ). – 3 , – .
- (resource pooling) – () . , . .
It is important to understand that the cloud characteristics described above are not taken from the ceiling, but are a logical conclusion from the concept of utility computing. And a public service should have these characteristics within the concept. If one or another characteristic does not match, the service does not get worse and does not become "toxic", it just ceases to be cloudy. Well, who said that all services are required?
Why am I talking about this separately? In the 10 years since the NIST definition was introduced, there has been a lot of controversy about "true clouds" as defined. In the United States, the phrase “corresponds to the letter of the law, but not the spirit” is still sometimes used in the judicial sphere - and in the case of cloud computing, the main thing is spirit, resources for rent in two clicks.
It should be noted that the above 5 characteristics are applicable to a public cloud, but when moving to a private cloud, most of them become optional.
- Broad network access - Within a private cloud, the organization has complete control over both generating capacity and consumer customers. Thus, this characteristic can be considered automatically fulfilled.
- (measured service) – utility computing, . ? , , - . . : chargeback ( ) showback ( , ).
- (on demand self service) – , . - - . – .
- (rapid elasticity) – . . – .
- (resource pooling) – , . .
Question: So what exactly is your private cloud? What does a company need to buy and implement to build it?
Answer: a private cloud is a transition to a new administrative model of IT-Business interaction, which is 80% administrative measures and only 20 technologies.
Paying only for consumed resources and easy entry, without having to bury hundreds of millions of oil in capital expenditures, has created a new technological landscape and the emergence of billionaire companies. For example, modern giants Dropbox and Instagram appeared as startups on AWS with zero infrastructure of their own.
It should be emphasized that cloud service management tools are becoming much more proxy, and sourcing and quality control are becoming a key CIO responsibility. Let's look at the challenges of these two new responsibilities.
Emerging as an alternative to the classic heavy infrastructure with its own data centers and hardware, clouds are deceptively light. It's easy to enter the cloud, but the issue of exit is usually bypassed. As with any industry, cloud providers are committed to protecting businesses and making competition more difficult. The only serious competitive moment arises only during the initial choice of a cloud service provider, and then the supplier will make every effort so that the customer does not leave him. Moreover, not all efforts will be directed at the quality of services or their range. First of all, it is the delivery of unique services and the use of non-standard system software, which makes it difficult to switch to another provider. Respectively,When choosing a service provider, it is necessary to simultaneously form a transition plan from this provider (in fact, a full-fledged DRP - disaster recovery plan) and think over the architecture of data storage and backup copies.
The second important aspect of the new responsibilities of the CIO is to control the quality of services from the supplier. Almost all cloud providers comply with SLA according to their own internal metrics, which can have an extremely indirect meaning to the customer's business processes. And accordingly, the implementation of our own monitoring and control system is becoming one of the key projects when transferring significant IT systems to a cloud provider. Continuing the topic of SLA, it should be emphasized that the vast majority of cloud providers limit liability for non-fulfillment of SLA in a monthly subscription fee or a fraction of the payment. For example, AWS and Azure, upon exceeding the threshold of availability of 95% (36 hours per month), will make a 100% discount to the monthly fee, and Yandex.Cloud - 30%.
https://yandex.ru/legal/cloud_sla_compute/
And of course, we must not forget that clouds are not only performed by Amazon-class mastodons and Yandex-class elephants. There are also smaller clouds - the size of a cat, or even a mouse. As the CloudMouse example showed, sometimes the cloud just picks up and ends. You will receive no compensation or discount - you will receive nothing but total data loss.
In view of the above problems with the implementation of high-class IT systems of business criticality in cloud infrastructures, the phenomenon of "cloud repatriation" has been observed in recent years.
By 2020, cloud computing has passed the peak of inflated expectations and the concept is on its way to a ditch of frustrations (according to Gartner's hype cycle). According to research by IDC and 451 Research up to 80% of corporate customers return and plan to return loads from the clouds to their own data centers for the following reasons:
- Increase availability / performance;
- Reduce costs;
- To comply with IS requirements.
What to do and how is everything "really"?
There is no doubt that the clouds have come in earnest and for a long time. And every year their role will increase. However, we do not live in the distant future, but in 2020 in a very definite situation. What to do with the clouds if you are not a startup, but a classic corporate customer?
- The clouds are primarily a place for services with an unpredictable or pronounced seasonal load.
- In most cases, services with a predictable stable load are cheaper to maintain in your own data center.
- You need to start working with clouds with test environments and low-priority services.
- Considering the placement of information systems in the cloud begins with the development of a methodology for going from the cloud to another cloud (or back to your own data center).
- Placing an information system in the cloud begins with developing a backup scheme for the infrastructure you control.