SRE vs DevOps: Understanding the Difference

Do organizations need to choose between Site Reliability Engineering (SRE) and DevOps?  Are there differences between SRE and DevOps?

DevOps is NOT a position, it’s a methodology and/or approach that combines software development and IT operations. The goal of DevOps is to ensure that development teams take responsibility for code throughout its entire lifecycle, including ongoing maintenance in production. Through practices like continuous delivery, DevOps allows developers to validate application updates before deployment. In addition to continuous delivery, DevOps could encompass activities such as software engineering, release management, testing, integration, configuration management, and real-time monitoring; these skills have very specific expertise, taking years to develop and it is extremely rare to find a person who is an expert in all of them.

SRE takes a collaborative approach between software engineering and systems operations. SRE teams are responsible for identifying and preventing issues that could lead to system downtime or performance issues. SRE balances both development priorities such as speed, quality, design, agility and innovation with operational priorities like security, performance, availability and maintainability. And uses many types of tools depending on the technological stack and tool availability, which also makes it difficult for a single person to be an expert in the specific stack and combination required.

So, when we say that companies have teams with an SRE perspective and a DevOps perspective, we are saying that they have teams focused on reliability and teams focused on the full development cycle, but both teams embracing the DevOps culture.

It is very common to observe in the Job Descriptions that they need one person to cover ALL the needs of the DevOps area or the SRE area, although it is true that everyone needs to "understand" everything, it is very different than to be an expert in everything.

Comparison between SRE and DevOps

Most organizations have many departments working on the same product. However, the product can fall apart if these departments do not work together. DevOps helps remove disagreements between team members and brings them together under a shared vision. DevOps's goal is to enable each department to make optimal use of resources. SREs, on the other hand, do not target silos directly but push everyone to discuss. By doing this, they share ownership of a product with everyone working on it across the company.

Companies know that software will fail at some point if not tested regularly. DevOps uses automated testing to find mistakes and mitigate risks. By doing this, DevOps ensures that the teams don’t repeat mistakes. SREs use two methods to check failure: service level indicators and service level objectives. SLIs measure failures per request over time, and SLOs represent the success percentage of SLIs.

DevOps uses four metrics to measure performance. These include deployment frequency, time to restore service, lead time for changes, and change failure rate. SREs use four signals, traffic, latency, saturation, and errors to measure progress (golden signals). Developers must take established benchmarks against each metric into account for measurement.

SRE teams comprise site reliability engineers with prior experience in software development and operations. DevOps teams can include several members like quality analysts, software developers, release managers, system administrators, product owners, and system reliability engineers, among others.

DevOps and SREs include similar tools that include containers, microservices, continuous integration, continuous deployment, infrastructure as code, resilience testing, and monitoring systems among others.

SRE’s focus is to create highly reliable and ultra-scalable applications. SRE’s responsibilities primarily center around ensuring and maintaining the reliability of the application over making quick changes. On the other hand, DevOps focuses on creating production environments wherein developers have more control. DevOps’s goal is to set up CI/CD pipelines across all the stages of the product for agile development.

DevOps employs small changes gradually instead of deploying large-scale changes to the software application. By doing this, DevOps applications face fewer bugs and consist of excellent review management. SREs roll back early and often to make the product error-free. To implement changes, SREs validate updates with canary releases. Additionally, SREs responsibilities include balancing reliability with frequent updates.

SRE works to eliminate tedious tasks by identifying and removing tasks that take more than fifty percent of an engineer’s time. Also, SREs prepare specific codes for different operations and add the codes to a playbook. DevOps automation practices create feedback loops between the operations and development teams. DevOps’s goal of automation is to push iterative updates faster to the applications in production.

In summary, the comparison between Site Reliability Engineering (SRE) and DevOps highlights that both approaches share common tools and objectives in the search for reliability and efficiency in the development and operation of systems and services; and they also overlap. However, they differ in their core approaches: SRE prioritizes reliability and scalability, promoting the elimination of tedious tasks and constant validation of changes, while DevOps focuses on automation, collaboration, and gradual implementation of changes to achieve a greater agility. These differences allow both approaches to adapt to different contexts and organizational needs, and their choice is not mutually exclusive.