Cloud computing is a technology where applications are deployed on immutable servers, which increases performance and reduces time spent with long differences. Cloud computing, referring to the related term, ‘public cloud’, delivers computing as a service rather than a product. It enhances manageability and requires less maintenance by adjusting resources which meet varying industry demands. This service hides many complexities of running background tasks like Amazon web service Lambda. The market share of cloud computing is expected to exceed $59 billion in 2015.

The classification of Cloud Computing services can be done in three parts:-

• Software as a service (SAAS): The SaaS web delivery model eliminates the need to install and run an application on an individual server. With the SaaS model, maintenance and support can be streamlined because vendors manage Applications, Data, storage, Middleware, virtualization, and everything. e.g.Microsoft365 and GoogleDocs.
• Platform as a service (Paas): These services are used to access from a web browser. PaaS providers host hardware and software infrastructure, and businesses rely on them for critical services. Salesforce.com is a familiar PaaS provider providing Customer Enterprise relationship management. IT teams do not need to purchase and set up servers from scratch; data can be accessed from the provider’s server. This can raise security and data leak threats, but these risks can be mitigated by choosing a host with security accreditation and correctly applying data encryption techniques. PaaS providers offer Managed Linux and Windows OS, which allows more resources for development and fewer for maintaining or configuring the operating system.
• Infrastructure as a service: Virtualized resources are provided over the Internet in this service.IaaS providers host hardware, software, servers, and user applications and handle the task of resilience planning. It automates administrative tasks and policy-based services. Although IaaS is similar to PaaS, the difference is that there is more control over the operating system here.

As with growing industry demand, Many stalwarts of the hosting industry have started providing Cloud hosting services. Some top cloud hosting providers are:-

Company	Arvixe	ZipCloud	Site5	JustCloud	Siteground
Uptime	95.33%	100.00%	98017%	100.00%	99.90%

Lock-in: The biggest Concern:-

Cloud services enable building large infrastructures from micro-services without worrying about underlying communication and infrastructure between them. The core concern while adopting these services is lock-in to a specific provider.

• Even if we build infrastructure over the standard framework and tools, we have to go through transferring data and changing DNS.
• Some services bound their customer to code-level lock-in, which requires them to build applications in a specific way that is tightly integrated into their infrastructure and tailored to their system. e.g. Google App Engine.
• Some services like Amazon web service Lambda provide architectural lock-in but less code lock-in. In the first iteration of Lambda, we have to write the node.js functions, which are invoked either by an API or specific events. This can lead to hundreds of small parts. The hurdle is that we can’t run those functions on another provider system. Building our system around them is required to make them run, which generates high architectural lock-in.

An architecture oriented on micro-services, built on technology that can be used on various providers, can offset many trade-offs. Making on top of the service initially and moving parts of the service to somewhere else for better control may be the approach, but it requires a different approach.

How your business is getting impacted:-

• One of the most significant advantages of the Cloud is that it is offsite and remote hosting, preferably used in Content distribution networks (CDN). These CDNs can improve user experience for mobile and web applications and content.
• On cloud hosting, the user is supposed to use dynamically allocated resources. A dedicated resource can be provided on demand by the customer. Consequently, the hosting provider can render various hosting packages that satisfy varying industry needs, and the user pays only for the resources he has used.
• It increases resiliency and enables offsite backup at distributed data centres at different locations, establishing the DRBC (Disaster recovery and business continuing) platform.
• No cloud provider is the same. Each one offers different sorts of packages. To find out which fits the best, you must analyze use cases. Choose the hosting provider which best suits your IT needs.

As the Cloud is dominantly adopted in the market, it is also unravelling some critical technical challenges for the industry:-

• The different platforms of the Cloud cannot be compared relatively due to the lack of a standard methodology to measure capability.
• Performance cannot be assessed throughout the life cycle of infrastructure.
• SLAs (Service Level Agreements) are based on availability instead of capabilities of service provided.

CLoudQos is the first solution addressing the entire cloud system’s requirement by providing enterprises, hosting providers and cloud service providers the data, ensuring they select the best cloud service.

There could also be some criteria for selecting a cloud provider:-

Geographical aspect: While purchasing the Cloud, you should ensure where the physical data centre is located. Data centres in another country or region may fall and abide by the jurisdiction of that area.

Storage: Storage technology is also a significant concern when opting for the Cloud. It would be best if you asked your provider for the storage technology they are using. Is it redundant? If it is, then how are they going to encounter disk failures? Moreover, check for SSDs (Solid state drives) to see if they are available.

Issue with Hypervisor: You should enquire about the hypervisor being used. Many applications are supported for only compatible hypervisor. Some hypervisors also provide features that can protect the server even if the host is running fails. If you are moving your hosting to another provider, the existing service should be checked to see if it is available.

Network Connectivity: Network Connectivity may also be a crucial topic to check on. If the provider has more than one uplink to provide the connectivity, it will be helpful during the outage. Along with network uptime, it is also worth considering the bandwidth charges often hidden in the hosting price.

Support: While taking hosting, it is necessary to get acquainted with the asset provided, whether it is an email or a phone helpline. If your service runs 24/7, ensure that the provider gives 24/7 support. You may also check if the provider is a member of bodies or code of practice. E.g. SSA certification body.

Whether it is impossible to conduct a questionnaire, asking for essential things before taking service on a lease is recommended, which can prevent you from falling into a more significant loss.