Continuous integration is a software life-cycle process in which you will have a development team in-house where they will have a stack of code, regularly pushed, to a central repository. After the push, automated and rigorous tests are done on those new stack of code, integrated with your software product. The key aspect here is to find and address bugs very quick, improve the final software delivery to your customers and reduce time it takes to integrate another stack of release software update.

Continuous delivery is a software engineering approach in which teams produce software in short cycles, ensuring that the software can be reliably released at any time. It aims at building, testing, and releasing software with greater speed and frequency. The approach helps reduce the cost, time, and risk of delivering changes by allowing for more incremental updates to applications in production. A straightforward and repeatable deployment process is important for continuous delivery.

Microservices are single-function applications comprise small, self-contained units working together through APIs. A microservices architecture is faster and more agile than a traditional application architecture. A modification made to a small section of an application might require building and deploying an entirely new version. If you need to scale specific functions of an application, you may have to scale the entire application instead of just the desired components. This is where creating microservices can come to the rescue.

Infrastructure as code is the practice of treating infrastructure as if it were code — just like software, in fact. It helps in practices that include version control, peer review, automated testing, release tagging, release promotion, and continuous delivery. This makes it easier for organizations to govern changes over resources and ensure that security measures are properly enforced in a distributed manner (e.g. information security or compliance with PCI-DSS or HIPAA).

Monitoring is an important link in a DevOps toolchain. It allows IT organization to identify specific issues of specific releases and to understand the impact on end-users. A typical monitoring related activity include Performance of IT infrastructure, End-user response and experience and Production metrics and statistics. Information from monitoring activities often impacts Plan activities required for changes and for new release cycles.