Continuous Develivery
Continuous delivery is in the middle of CI/CD pipeline: after unit tests validation (CI), it is responsible of building the artifacts and perform essential system integration tests, ready for deployment (CD).
Continuous integration ensures software components work atomically, that all individual parts of the software produce expected results. However, unit tests do not test the software works in all supported heterogenous ecosystem, with different versions of OS distributions bundled with their specific stack of libraries and tools.
Continuous delivery platforms provide solution to build and publish software artifacts for many software ecosystem and perform advanced system integration tests to secure deployments in heterogenous production environments.