With the growing complexity of application development, organizations are increasingly adopting methodologies that enable reliable, scalable software. For over a decade, two similar concepts, DevOps and SRE, have been existing together in the world of software development. They may look like competitors. However, a closer view reveals that obvious rivals are complementary pieces of a puzzle that fit nicely together. DevOps is a broad philosophy and culture because it affects more major changes than SRE does. DevOps is more context-sensitive. DevOps is relatively silent on how to run operations at a detailed level. Site Reliability Engineering (SRE), on the other hand, relatively defined responsibilities. Its remit is generally service-oriented and ends user-oriented rather than the completely business oriented.
This chapter from the book "The Site Reliability Workbook" explains how DevOps and SRE facilitate building reliable software, where they overlap, and when they can efficiently work side by side. In addition, how they help product managers, CTOs, and other executives that seek ways to improve the reliability of their systems without victimizing the speed of innovations.
Read more at 
Link
