DevOps is a set of practices that combines software development and IT operations. It aims to shorten the systems development life cycle and provide continuous delivery with high software quality. DevOps is complementary with Agile software development; several DevOps aspects came from Agile methodology. DevOps allows Agile Development Teams to implement Continuous Integration and Continuous Delivery. This helps them to launch products faster into the market. DevOps is a philosophy and when philosophy becomes a job, this job will not be something easy to do. DevOps is full of challenges and learning, it needs more skills than just the technical ones, a good understanding of complex technical problems and business needs at the same time.
Tools
In the DevOps world there's been an explosion of tools in release for CI/CD Tools (jenkins), configuration management tools (puppet, chef, ansible,), orchestration (Kubernetes), monitoring tool (Nagios), virtualization and containerization (AWS, OpenStack, docker) and many more.