Site reliability engineering

Site reliability engineering (SRE) is a discipline that incorporates aspects of software engineering and applies them to infrastructure and operations problems. The main goals are to create scalable and highly reliable software systems. According to Ben Treynor, founder of Google's Site Reliability Team, SRE is "what happens when a software engineer is tasked with what used to be called operations."
Roles.
A site reliability engineer (SRE) will spend up to 50% of their time doing "ops" related work such as handling issues, spending time on-call, and manual intervention. Since the software system that an SRE oversees is expected to be highly automatic and self-healing, the SRE should spend the other 50% of their time on development tasks such as adding new features, such as for scaling or automation. A site reliability engineer is usually either a software engineer with a good administration background or a skilled system administrator with knowledge of coding and automation.
DevOps vs SRE.
Coined around 2008, DevOps is a philosophy of cross-team empathy and business alignment. It's also been associated with a practice that encompasses automation of manual tasks, continuous integration and continuous delivery. SRE and DevOps share the same foundational principles. SRE is viewed by many (as cited in the Google SRE book) as a "specific implementation of DevOps with some idiosyncratic extensions". SREs, being developers themselves, will naturally bring solutions that help remove the barriers between development teams and operations teams.
DevOps defines five key pillars of success:
SRE satisfies the DevOps pillars as follows: