Platform as a Service - Cloud Foundry

Platform as a service (PaaS) ---

Platform as a service (PaaS) is a category of cloud computing services that provides a platform allowing customers to develop, run and manage Web applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.

Cloud Foundry is an open source cloud platform as a service (PaaS) on which developers can build, deploy, run and scale applications on public and private cloudmodels. VMware originally created Cloud Foundry and it is now part of Pivotal Software.

*PCF – Pivotal Cloud Foundry:

1. Its a multi cloud application platform where it serve as a PaaS called Stackato with its version 4 as latest which is governed by CFF (Cloud Foundry Foundation) Organization .. 

2. Its an Open Source Sw Foundation .. Primarily written in Ruby & GO & Java Languages .. 

3. A commercial version called Pivotal Cloud Foundry (PCF) is available from Pivotal. It provides extra tools for installation and administration not included in the OSS product – Pivotal Web Services (PWS) is an instance of Pivotal Cloud Foundry hosted on Amazon Web Services (AWS)... 

4. Cloud Foundry supports the full lifecycle, from initial development, through all testing stages, to deployment. It is therefore well-suited to the continuous delivery strategy. 

5. You can be demand in market with this Certification - Cloud Foundry PaaS Certification program 

6. Developers require an additional tool simply, the Cloud Foundry cf Command Line Interface. It is written in Go. Installers exist for MS Windows, MacOS, and Linux.

*How it works: 

1. When an application is deployed to Cloud Foundry, an image is created for it and stored internally. 

2. The image is then deployed to a Warden container to run in.

3. For multiple instances, multiple images are started on multiple containers. 

4. This is where BOSH comes in - Cloud Foundry's internal Controller uses BOSH to get the underlying infrastructure to spin up virtual machines to run the Warden containers on.

5. When an application is deleted, all of its containers are destroyed and their resources are freed for other applications to use.

6. If the application instance crashes, its container is killed and a new Warden container is started automatically.

7. A container only ever runs one application ensuring isolation, security and resilience.

8. A load-balancing router sits at the front of Cloud Foundry to route incoming requests to the correct application - essentially to one of the containers where the application is running.

-- Happy Learnings :)