A Walk through on IaaS, PaaS and SaaS
To understand about cloud computing and the cloud services that are available in the market, we first need to start with the three core categories of cloud computing services. Let’s understand what these categories are and what do they offer?
Windows Azure offers compute in three matrices: -
1. Infrastructure as a Service (IaaS)
2. Platform as a Service(PaaS)
3. Software as a Service(SaaS)
These offerings are based on permissions and responsibilities which allows us to manage our applications and environments.
The following is a side by side detailed comparison: -
1. Infrastructure as a Service: -
IaaS provides servers in the cloud (virtual machine) that can be completely controlled by the users. Users would have a broad range of permissions in the server from managing the OS to their applications.
This service gives a glimpse of typical on premises virtual machine, which allows us to login remotely and manage it.
If you need a solution that requires a custom third party application or multiple applications running on a single machine or the ability to turn on on-premises packaged applications, then IaaS might be a good option.
In addition to that you can leverage a range of services including detailed billing, monitoring, log access, security, load balancing, clustering, storage resilience (i.e. backup), replication and recovery. All these services are policy driven and facilitate IaaS users to implement greater levels of automation and Orchestration for important infrastructure tasks.
Ex: — A user can implement policies to drive load balancing to maintain application availability and performance.
To make the environment ready, the user can create a VM, install OS, middleware (such as DB, application server) and deploy the application. Users can create storage buckets for workload and backups.
With the help of other services, users can track cost, monitor performance, balance network traffic, troubleshoot application issues, manage disaster recovery and much more.
2 Platform as a Service (Paas)
PaaS facilitates builds and supplies a resilient and optimized environment in which we can install applications and data sets.
Users can focus on designing and running their applications and not worry about constructing and maintaining the underlying infrastructure and services.
Azure cloud service has two components, the application and a configuration file. Web role and worker roles combination is required to execute the application.
A web role is an azure VM that is pre-configured as a web server (running IIS) and automatically loads the applications when the server is up. It creates public endpoints for the application, which might be a web site or a web api.
Worker Roles runs in parallel to web role and are responsible for performing computation functions to support our applications. Web role job is to accept user’s input and queue an action for the worker role to process at later time. This makes web role more responsive and allows to file and forget the tasks to be processed later.
PaaS offers services like compute and storage infrastructure, version management and compiling and testing services that help developers design their applications more rapidly and efficiently.
PaaS is good for the following scenarios: -
i) To design and deploy cloud based applications
ii) Analytics or BI
We just have to seed our code to any of the code repository (Git, Bitbuket, Codeplex,TFS or Dropbox) to push to our web site and Azure will take care of the rest like CI and CD. CD requires us to write some configurations to make it automated.
3 Software as a Services(SaaS)
The software which is built and hosted to get things done (like Office 365,Azure configuration portal ,google drive etc.
