Deployment models

This approach generally appears when an organization is planning to use an IaaS-based service model. In such cases, before selecting a CSP, we need to understand what type of cloud service model we are looking for. Many of the organizations decide to create their own data center and launch a cloud environment with the help of OpenStack. One of the advantages in the long term would be the cost benefit, but this approach does take a large amount of investment.

Having said this, as illustrated in the following diagram, there are three deployment models for the cloud, based on which an organization has to decide which one to choose from:

Let's briefly look into each of them: 

• Public cloud: In this type of offering, the CSP opens up the service for everyone and anyone willing to pay for the service. This is one of the most common models that is being preferred by startups and mid-sized organizations. One of the benefits of this approach is that the initial investment needed is far less as, the organization will pay as per their resource usage in the cloud environments.
• Private cloud: As the name suggests, private cloud is meant to be used within organizations. In this type of approach, the services are not being offered in public, instead are made to be used for resources within the organization itself. Thus, entire responsibility related to the governance and security maintenance becomes the responsibility of the organization. Organizations choosing this approach generally use OpenStack for their environments.
• Hybrid cloud: In this type, some of the assets are being managed in the internal private cloud while others are moved to the public cloud. Servers can be managed internally, but for data storage, we can use Amazon S3 or Amazon Glacier. Thus, an organization can plan out which assets are costly to handle internally and if the cloud is a cheaper option, then those assets are migrated to the cloud. Many organizations also decide to use a multi-cloud-based approach where services such as servers can be managed by cloud providers such as Linode and DigitalOcean, which are quite cheap and reliable, while other services such as storage, message broker, and much more rely on the AWS platform.

Relying on a single cloud provider such as AWS might prove to be expensive and you will always have your finance team chasing you up over high cost. From what I have observed over the course of many years as a part of cost optimization projects, I prefer to use the hybrid cloud, where servers and services are distributed among different cloud providers such as AWS, DigitalOcean, and Linode. This approach is great but you will need a good amount of time to do all configurations. This approach is generally not preferred by startups that have limited bandwidth and might not have dedicated solutions/DevOps architects to take care of the infrastructure.