Cloud computing is a type of computing that provides multitenant or dedicated computing resources such as compute, storage, and network to cloud consumers on demand. It comes in different flavors that includes cloud deployment models and cloud service models.

Cloud deployment models describe the way cloud resources are deployed, such as behind the firewall and on-premise exclusively for a specific organization, and this is called the private cloud; or cloud resources that are available to all organizations and individuals, and this is called the public cloud; or cloud resources that are available to a specific set of organizations that share similar types of interests or similar types of requirements, and this is called the community cloud; or cloud resources that combine two or more deployment models, and this is known as the hybrid cloud.

Cloud service models describe the way cloud resources are made available to cloud consumers. It can be in the form of a pure infrastructure, where virtual machines are accessible and controlled by a cloud consumer or end user, and this is called Infrastructure as a Service (IaaS); or a platform where runtime environments are provided so installation and configuration of all software needed to run application are already available and managed by a cloud service provider, and this is called Platform as a Service (PaaS); or Software as a Service (SaaS), where a whole application is made available by a cloud service provider with the responsibility of infrastructure and platform remaining with the cloud service provider.

Cloud computing has a few characteristics which are significant such as multitenancy, pay-as-you-use (similar to electricity or gas connection), on-demand self-service, resource pooling for better utilization of compute, storage; network resources, rapid elasticity for scaling up and scaling down resources based on needs in an automated fashion, and measured service for billing.

Over the years, usage of different cloud deployment models has varied based on use cases. Initially, the public cloud was used for applications that were considered non-critical while private cloud was used for critical applications where security was a major concern. Hybrid cloud usage evolved over time with experience and confidence in the services provided by cloud service providers.

In a similar way, there was a usage pattern for cloud service models too. As we usually do in a normal traditional environment, it was easier to adopt IaaS as there is complete control. Over time, organizations realized the cost of managing resources in the cloud as the efforts are the same in managing resources, considering security configurations, and other configurations. Hence, IaaS was becoming difficult day by day with the evolution of PaaS. PaaS has evolved over the years and its approach is much wider, and its services include multiple programming languages such as .NET, Java, PHP, Python, and Ruby.

In simple English, PaaS provides infrastructure as well as a runtime environment to deploy an application. The difference is the end user doesn't have control on infrastructure while we can configure a runtime environment and debug an application remotely and troubleshoot issues to some extent. There are PaaS offerings where you can have dedicated infrastructure resources for application deployment, but even in that case, control of infrastructure is in the hands of cloud service providers. In short, we as cloud users need not to worry about downloading different web servers, database servers, and other required software and install them on a machine and maintain them. We don't even need to worry about updating them to newer versions. Cloud service providers are responsible for maintaining availability of the application and its resources. However, as users, we need to follow best practices to configure applications to have a highly available application considering different services provided by the cloud service provider.

Comparison – PaaS and IaaS

Let's visualize how the process workflow is executed in terms of a traditional model or in IaaS, and then we will compare it with PaaS. In a traditional environment, the infrastructure provisioning process takes place in a different manner than the acquisition of a virtual machine in a cloud subscription.

While in the case of PaaS, the flow has less complications than the traditional or IaaS process.

However, the approval process in the cloud environment too has costs associated with it, so organizations keep their own sets of e-mail approval processes to create a virtual machine or to provision any PaaS offering.

Over the years, PaaS has gained its momentum and many organizations have realized that there are less complexities and less management overhead involved in it. Hence, many customers are leaning towards the PaaS offering, as they don't wish to manage virtual machines and apply security policies in the cloud and maintain all of them. In IaaS, as users, we need to configure high availability and scalability, and it is more complicated compared with PaaS.

PaaS offerings manage load balancers and high availability with little configuration and hence save a lot of time, and the architecture is more clear. We need to remember that most of the control is available with cloud service providers and hence we have less things to manage. Cloud service providers have more control and they implement all the best practices and a standard pattern to fulfill the SLAs attached with PaaS offerings. Governance wise, PaaS is less flexible in terms of applying policies as it is a shared environment and is standardized as well. Managing PaaS is also less costly compared with IaaS. In the case of IaaS, we need to manage everything the way we manage on-premise.

In short, those who know better about infrastructures and platforms manage them with efficiency so we have less overhead.

An Application Platform as a Service (aPaaS) provides features to design, develop, deploy, and manage an application life cycle, enabling effective resource utilization, agility, and faster time to market. It is getting popular now-a-days as it has less overhead and less complexities of managing resources for the application life cycle management. Usage of thick clients is an old story now and PaaS providers have realized the trend. Developers want offerings all in once place where they can develop, compile, package, and deploy at them. PaaS is accessed through web browsers such as Firefox, Chrome, or Internet Explorer. Most PaaS providers have come up with offerings to support developers within browser IDEs to develop applications. In recent times, DevOps has also gained momentum and PaaS along with the DevOps culture is breaking a lot of barriers in the traditional culture of IT. In the next section, we will discuss DevOps and then we will see benefits of PaaS in DevOps.

DevOps is more about the culture of an organization, processes, and technology to develop communication and collaboration between Development and IT Operations teams so as to manage the application life cycle more effectively than the existing ways of doing it. We often tend to work based on patterns to find reusable solutions from similar kind of problems or challenges.

Over the years, achievements and failed experiments, best practices, automation scripts, configuration management tools, and methodologies became an integral part of the culture. This helps to define practices for ways of designing, developing, testing, setting up resources, managing environments, managing configuration, deploying an application, gathering feedback, performing code improvements, and doing innovations. It helps to train people to think that drive the DevOps culture at every stage.

The DevOps culture is considered to be an innovative package to integrate the Dev and Ops teams in an effective manner that includes components, such as continuous build Integration, continuous testing, cloud resource provisioning, CD, continuous deployment, continuous monitoring, continuous feedback, continuous improvement, and continuous innovation, to make application delivery faster as per the demands of the agile methodology.

Considering the way we have been doing things to manage applications over the years, it is a challenge to change the culture. Mr. David Gleicher created the formula for change, and later it was refined by Kathie Dannemiller. This formula is still relevant as it provides a model to assess the relative strengths affecting the success possibilities of organizational change initiatives.

As per the formula, three factors must be available for a meaningful organizational change to take place. I just tried to classify different things in these three factors:

If the product of these three factors is greater than R = Resistance, then change is possible. If any one factor is absent (zero) or low while D, V, and F are multiplied, then the multiplication will be zero or low and therefore it may not overcome the resistance. Even without numerical values, the outcome of this formula is very much in the favor of change considering the values.

To bring an organization-wide change, we must consider the possibility of dissatisfaction in people and try to bring the change in mindsets by sharing industry trends, leadership ideas, best practices, and competitor analysis to identify the necessity for change. Hence, to ensure a successful change, it is the need of the hour to use influence and think strategically to create a vision and identify the basic steps toward it. To change the culture of an organization effectively, we the people need to bring in an agile, standardized environment, uniform automation processes orchestration, and DevOps enablers. Essentially, it means the combination of people, processes, and tools to achieve efficiency.

In other words, the DevOps culture is not much different than the organization culture, which has shared values and behavioral aspects. It needs adjustments in mindsets and processes to align with the new technology and tools.

At the end of the day, the ball is in our court and we should remember that we can't make an omelette without breaking a few eggs. To be more precise, the early bird catches the worm.

In the next section, we will describe in detail about the role and benefits of PaaS and aPaaS in DevOps.