Site Reliability Engineering (SRE) vs DevOps: Key Differences Explained

DevOps describes a cultural and technical approach to collapsing the traditional divide between development and operations. It aims to erode the wall separating development and operations teams, and it fosters a culture of shared responsibility for the software delivery life cycle. Additionally, DevOps is as much about speed—speed in terms of continuous delivery, automation, and feedback loops contributing to fast product engineering without compromising quality or operational excellence.

In many respects, DevOps is born from Agile concepts and the Agile movement, moving Agile ideas from a development and design space to a software operations space. Many organizations now work with specialized devops development and consulting services to help implement these practices effectively. DevOps is focused on improving collaboration and communication between Dev and Ops to shorten development cycles, improve deployment velocity, and produce better and more reliable software applications. This can include, but is not limited to, creating and enabling continuous integration and delivery pipelines, treating your infrastructure as code, automated testing, and other initiatives to enable a more efficient software development and delivery lifecycle.

DevOps is more about behavior and culture than it is about defined roles or activities. When teams adopt a DevOps mindset, they design their culture around shared responsibility, ongoing learning from success and failure, and taking advantage of asynchronous improvements. Collaborative behavior leads to organizations being intelligent when responding to external forces that challenge their market position, while enhancing the responsiveness to user-directed employee engagement exploration, and all while keeping the system stable.

Site Reliability Engineering (SRE) is an engineering discipline that uses software engineering to solve infrastructure and operational problems. SRE has its roots in Google, where Ben Treynor Sloss defines SRE as “what happens when a software engineer is tasked with what used to be called operations”. SRE relies on treating operations as a software problem and using software engineering approaches to solve operations issues.

Site reliability engineering is focused on the reliability and availability of the site systems. SRE teams create service-level objectives (SLOs) and error budgets to quantify a site’s downtime or errors. The SLOs and error budgets provide a measure for the trade-off between reliability and pace of development of features and provide a framework for meeting challenges to improvement. If the error budget is met, the development teams can more freely deploy new features; when the error budget is depleted, time must be spent on resolving issues and improving reliability.

SRE teams normally consist of engineers with both software development and systems operations backgrounds who can use their coding skills to automate manual operational tasks, create monitoring systems, develop scalable infrastructure, and plan for disaster recovery. Organizations implementing SRE often utilize managed backup services to ensure robust disaster recovery capabilities. SRE builds more reliable and scalable systems by treating infrastructure as code and applying software engineering best practices to operations.

In order to understand the differences between SRE and DevOps, it is helpful to consider a few of the key dimensions in which the two begin to diverge:

One of the most important distinctions between DevOps and SRE is philosophical. DevOps is primarily a cultural movement to eliminate silo and throughput barriers between development teams and operations teams while fostering working collaboratively, communicating, and taking joint responsibility over the entire software delivery lifecycle.

Conversely, SRE serves as a prescriptive, engineering-focused vehicle for addressing systems operation challenges by adopting software engineering principles. Whereas DevOps describes how organizations should operate, SRE specifies an implementation style to achieve it. Google often refers to SRE as “a specific implementation” of DevOps “but with some hilarious extensions”.

Traditional DevOps does not entail specific teams or roles but is focused on blending responsibilities of development and operations into existing teams. Adopting DevOps in an organization would manifest in many different forms—possibly having an operations engineer on each development team, or an organization could create a DevOps team to partner and collaborate with existing development teams.

Comparing SRE vs. DevOps, there is certainly a much more defined team structure, as SRE does create specific SRE teams with associated roles and associated development teams. SRE teams are typically engineers with specialization–concentrating on reliability, performance, and scale. They often operate independently from the development teams, acting as a consultant for reliability.

In evaluating SRE and DevOps, SRE’s and DevOps approaches to metrics show significant differences. DevOps is typically measured by deployment frequency, lead time for changes, change failure rate, and time to restore service. These metrics align with the goals of DevOps of delivery velocity and stream of improvement.

SRE focuses on SLIs (service level indicators), SLOs (service level objectives), and error budgets as their primary metrics. These metrics provide a quantitative structure for balancing reliability and innovativeness. The specific metric of error budget offers the best opportunity for organizing measurement based on deciding on how to balance a new feature versus reliability iteratively.

The technical emphasis also makes clear the difference between DevOps and SRE. DevOps practices often emphasize advancing continuous integration/continuous delivery (CI/CD), infrastructure as code, and automation across the software delivery pipeline. The technical emphasis is ample, spanning the development and the operations phases.

SRE has a much narrower technical emphasis, primarily around reliability, scalability, and performance. Security is also a major concern, with many organizations implementing managed cloud security services to complement their SRE strategy. Thus, SRE teams develop deeper capabilities in monitoring, alerting, capacity management, and emergency response. They build automated systems to tackle operational work while also emphasizing a punchline term, toil, which means that work that can be automated is better automated because it’s usually manual and repetitive.

Whereas, in the DevOps atmosphere, problems are usually solved through collaboration, with the development and operations teams becoming partners in solving problems, the emphasis is on shared accountability and removing the walls between groups to solve development and operational problems together.

In SRE, a more engineering-centered approach is taken towards solving problems, and SRE teams are typically expected to follow software development practices to address operational problems. SRE teams typically have detailed postmortems for incidents, often using hindsight bias and blaming the individual or individuals. The blameless postmortem process, however, has other potential lessons (not related to blaming) that emphasize learning rather than fault.

While being distinctive, SRE and DevOps demonstrate notable overlap, which is why it’s common to lump them together:

SRE and DevOps both value automation to limit the need for manual intervention and eliminate human error. They both strive to measure outcomes through meaningful metrics, with both relying on data for decision-making. Both approaches value continuous improvement and learning from failures, with the ideal culture around both SRE and DevOps being one in which failure is viewed as an opportunity to improve systems or processes, rather than an opportunity to point fingers or lay blame.

SRE and DevOps both value cross-functional collaboration; however, they approach this collaboration differently. Both approaches seek to accelerate software delivery while simultaneously maintaining system reliability, but they simply balance those two priorities differently.

The decision to use DevOps vs. SRE—or both – will depend on a number of factors within your organization.

DevOps may be more appropriate for organizations that:

• Need to overcome significant cultural barriers between development and operations
• Seek to improve collaboration across teams without major structural changes
• Are earlier in their automation and delivery optimization journey
• Want flexibility in implementation rather than a prescriptive approach

SRE might be better suited for organizations that:

• Have mature development practices but struggle with reliability at scale
• Need a structured approach to balancing feature development with reliability
• Have the resources to establish dedicated reliability teams
• Deal with complex distributed systems where reliability engineering is critical

Many organizations have successfully leveraged both approaches, using DevOps as a broader cultural play while using SRE practices to help address specific reliability challenges. Organizations undergoing digital transformation often use cloud migration solutions as a foundation for implementing these practices. Using DevOps to foster collaboration while using SRE as the basis for implementing reliability is a very effective approach.

A globally operating e-commerce company had difficulties with both speed of development and reliability of its systems as its business grew very quickly. Initially, they used DevOps practices to eliminate silos between their development team and their operations team and introduced CI/CD pipelines and infrastructure as code. Through these changes, the company improved the frequency of deploying code and reduced lead times. At the same time, the company still had many reliability issues during periods of high traffic.

To mitigate these problems and improve upon their DevOps culture, the company adopted SRE principles. The company put together SRE teams that were dedicated to the task of defining borrowing from SRE principles, defining the SLOs and error budgets for the most critical services. The SRE teams partnered with developers with the goal of implementing better monitoring, alerting, and automated recovery.

The combination of the two approaches turned out to be highly productive. The DevOps culture provided the collaborative process necessary for the success of the SRE teams, while SRE offered methodology for getting better reliability. Development teams were given firm guidelines on when to focus on new features versus reliability, and there was transparency of how much of the budget was remaining. Over time, both reliability and speed of development improved, with availability going from 99.9% to 99.99% while frequency of deployment doubled.

In this instance, we see DevOps and site reliability engineering (SRE) aligned together in a thoughtful way. The values that come with DevOps created a setting to refine SRE practices, while SRE brought concrete mechanisms to achieve DevOps goals around reliability and automation.

At AppRecode, we acknowledge the difficulty with distinguishing between SRE and DevOps. Our experienced consultants will assist organizations in determining which modernization approach, or combination of approaches, best achieves their needs and goals.

Our DevOps services are to establish cultural transformation, process improvement, and technical implementation. We help organizations break down boundaries between development and operations. We support organizations in establishing CI/CD pipelines, infrastructure as code, or both. Our consultants work with your teams to cultivate a culture of collaboration and shared ownership.

For organizations looking to advance SRE, we have specialized consultants who will focus on risk engineering, monitoring, and automation. Our SRE consultants can help establish SLOs and error budgets, deploy robust monitoring tools, or develop automated remediation solutions. We will also build capacity through building and training SRE teams to establish the skills to keep systems reliable and/or durable at scale.

Numerous clients have achieved positive results from our integrated solution that incorporates both the DevOps and SRE paradigms. We have worked with clients to develop DevOps culture while implementing SRE practices for critical systems. This approach draws on components of both to improve delivery speed and reliability.

Although DevOps and SRE have similar goals around improving software delivery and reliability of systems, they are outcomes of different frameworks to approach these goals. DevOps frames its emphasis on cultural change and collaboration across development and operations, while SRE applies principles of software engineering to the challenges involved in operations with an emphasis on capturing measures that allow for calculating and maintaining reliability. 

Many organizations have had success with both systems, implementing DevOps as a broader organizational culture and an implementation of SRE reliability issues. Within the frameworks of these two movements, organizations can make better choices about the quality of their software delivery and the workings of their operations.

As systems become more complex and business demands increase, both the principles of DevOps and SRE become more commonplace aspects of organizational design. Thoughtfully designing two frameworks to transmit either separately or collectively would offer two valuable propositions towards building reliable systems and sustaining the agile applications that are expected organizationally in today’s technology.

The primary difference between SRE and DevOps lies in their respective goals. DevOps is a cultural mindset that emphasizes collaboration between development and operations teams, while SRE is specifically applying the principles of software engineering on operational problems. DevOps tells you what to do, while SRE tells you how to achieve reliability.

No, an SRE is a type of DevOps engineer that tends to have a strong background in software engineering and experience focused on specific reliability issues, monitoring issues, and automating operational tasks. A DevOps engineer will typically work in a wider variety of roles across the software delivery pipeline focused on CI/CD, infrastructure as code, and collaborating with teams.

SRE also provides a more structured approach specifically aimed at improving system reliability through concepts like error budgets, SLOs, and reliability-specific engineering. Though, DevOps practices provide the fundamentals to promote reliability through improved collaboration and automated testing. The most effective method is often a combination of the cultural elements of DevOps and the rigor of reliability engineering practices from SRE.

Yes, organizations can and often do implement SRE and DevOps together. DevOps is a cultural foundation and framework to promote better collaboration; SRE implementation patterns build on the foundation to support reliability. Many organizations are recognized as successful in adopting DevOps principles broadly and adopt SRE principles for mission-critical systems and services.

SREs are typically expected to have strong software engineering skills, technical systems knowledge, situationally aware knowledge of monitoring and observability, and the ability to develop reliable artifacts and an understanding of how to design for reliability at scale. DevOps engineers, while still technical, are expected to have a mature understanding of development/operations knowledge, CI/CD, infrastructure as code, containers, and collaborative workflows. DevOps engineers may have the same mindset and knowledge of automation and problem-solving, but SREs may be expected to have a deeper understanding of operational “reliability engineering”.