SRE vs. DevOps: The Key Differences You Need to Know

Site Reliability Engineering (SRE) and DevOps are two popular methodologies utilized by many software developers to produce high-quality and reliable software. 

But one question keeps coming up constantly. That question is, «Are SRE and DevOps the same?»

This question holds significance for software providers who wish to improve software management processes and reduce downtime costs. According to Gartner, the cost of network downtime is about $5,600 p/minute.  

So you want to utilize these methodologies in the most efficient way in order to  ensure that your software does not contribute excessively to this cost. Ideally, you should aim for zero impact on downtime expenses.

Keep reading as we dive into the most important aspects you need to know to help you separate SRE from DevOps with clarity.  

What is Site Reliability Engineering (SRE)?

Site Reliability Engineering (SRE) connotes the principles involved in creating IT systems that are highly scalable, and hence, highly reliable. It focuses on post-release infrastructure management. SRE teams monitor and, if needed, improve software systems to accommodate new releases from development teams. 

Coined by Ben Treynor, the Senior Vice President of technical operations at Google, SRE focuses on observability to increase software availability. 

The SRE principles are geared towards automating the following items:

• Software monitoring
• Testing
• Incident response to reduce downtime and latency. 

The SRE team works closely with the development team to ensure features and overall software versions are of the highest quality — enough to meet Service-Level Agreements (SLAs). They also ensure that the software infrastructure is reliable enough to support releases and dynamic user-based activities.  

SRE makes use of an error budget, which is the tolerance for failure given to software during its operation, post-release. Where the error budget is exceeded, an alarm is raised on the reliability of software infrastructure, features, and even development processes. 

SRE is fundamentally guided by the principles of SLO, SLA, and SLI. 

SLOs are the goals your software application needs to meet to satisfy performance requirements. Your “performance requirements” are your service-level agreements (SLAs) or promises to users, and this performance is measured through metrics known as service-level indicators (SLIs).

For instance, let’s say you promise your users 99% uptime per week (168 hours). It means your error budget is 1% downtime per week and your SLA is the promise of 99% uptime per week. Your SLO is to meet this promise and your SLI is the metric through which you will measure the software performance.

Now, think of a scenario where your SLIs show that your software goes down 12 hours on average per week of 168 hours. This means:

• Uptime = 168-12 = 148 Hours or 92.8% (148/168x100)
• Downtime =  (12/168)x100) = 7.2%

As you can see, the downtime clearly exceeds the error budget of 1% downtime. Hence, you don’t meet your SLO and SLA.

Now, the role of SRE is to monitor and optimize processes to meet these agreements and objectives.

What is DevOps?

DevOps is a cross-functional methodology that aims to increase the speed and quality of software development and delivery. 

DevOps brings together the “development” and “operations” teams, removing them from a siloed environment. The unified team implements changes to the application at high velocity and maintains a suitable infrastructure to support this fast-paced deployment at all times. 

The goals of DevOps are primarily achieved through the principles of Continuous Integration and Continuous Delivery (CI/CD). 

Continuous Integration (CI) involves merging separate developer codes onto a central repository on a frequent basis, while Continuous Delivery (CD) involves building with and testing this code in test deployment environments to monitor results. 

CI/CD assures you of quality and reliability before release, utilizing automation to assess code for real-time change.  

SRE vs. DevOps: The key differences 

From the definitions above, you may have noticed that the focus of DevOps/SRE is on improving the quality of software delivery to achieve high reliability for users. Both utilize automation to reduce repetitive workflows during software testing and maintenance. 

However, there are multiple key distinctions between the two methodologies. We can separate these differences on the basis of the following:

• Core competencies
• Tools
• Team roles
• Use cases  

1. DevOps vs SRE: Differences in core competencies

When we talk about the core competencies of SRE and DevOps, we refer to the strategic capabilities that each methodology offers. 

These are the key differences between DevOps and SRE, in terms of  core competencies. 

i. DevOps covers speed and quality of delivery, SRE covers reliability of release

The main focus of DevOps is to release changes to software as fast and as high-quality as possible. 

To achieve this goal, DevOps seamlessly integrates pre-release software operations like code and infrastructure testing with development workflows like code writing and application-building. Through high-velocity testing and change management, it speeds up delivery and reduces the cost of custom software development. 

SRE, on the other hand, mainly focuses on optimizing the health of software infrastructure, like right-sizing cloud resources and ensuring business continuity through redundancy. It involves monitoring error budgets and making changes to infrastructure in the post-release environment The goal is to achieve maximum uptime and meet service-level objectives (SLOs). 

ii. DevOps automates development, SRE automates recovery/redundancy

Both DevOps and SRE utilize automation to improve the efficiency  of workflows. However, they use automation differently. 

While DevOps automates code building, monitoring, and code testing in test environments, SRE automates infrastructure monitoring, incident documentation, and incident recovery in the production environment. 

In other words DevOps automates to increase the speed of version releases, while SRE automates to reduce the Mean Time to Detect (MTTD) before incidents occur and Mean Time to Recovery (MTTR) after incidents occur.

Automation gives the IT personnel room for innovation, with DevOps innovating on development workflows and SRE innovating on observability and incident recovery workflows.

iii. DevOps develops features, SRE ensures features are reliable 

DevOps is concerned with developing features and improving the efficiency of this development process. 

DevOps workflows primarily create codes and then utilize operations management to seamlessly unify and test code. If the code fails to meet performance or quality requirements, the DevOps team writes new code to optimize features and software performance. 

SRE provides the quality requirements and indicators against which the performance of developed features is gauged. SRE monitors the performance of deployed software versions and features against SLOs. Through SLIs, it analyzes the compatibility of deployed features with the production environments in detail. It then offers feedback to the development team on the changes to be made. 

The DevOps team writes code all the time to build applications, while the SRE team may only write code to build more efficient automated workflows. 

iv. DevOps handles software debugging, SRE handles infrastructure debugging

Where there are issues with deployed software applications, especially when error budgets are constantly being exceeded, these issues are often either in the software code or in the supporting infrastructure. Remember that SRE engages in continuous intelligence gathering, and so, it is SRE that provides information on where loopholes exist. 

Depending on what this information points to, DevOps focuses on debugging code and making high-velocity collaborative changes to software code, while SRE focuses on debugging and improving infrastructure in both the test and production environments. 

SRE ensures that all supporting systems are adequate, and is more proactive in solving problems in the production environment.   

Also Read: The different types of programmers

2. SRE vs DevOps: Differences in terms of tools

Both methodologies make use of slightly different classes of tools to facilitate the achievement of their different core competencies. 

Let’s see how these differences play out.   

i. Tools used in SRE

Some of the tools that SRE uses to manage performance environments include: 

a. Application Performance Management (APM) tools

APM tools provide the SRE team with a detailed top-down overview of the software systems. They help visualize production performance metrics like CPU usage, memory, disk space, latency, traffic, errors, and saturation.

It is through APM tools that the SRE team monitors SLIs against SLOs. Some platforms that provide APM tools include:

• Datadog
• New Relic
• SolarWinds

b. Automated Incident Response (IR) tools

Incident response is key to maintaining availability in case of system failures and cyber attacks. 

Automated incident response tools utilize AI to monitor, analyze, contain, and remediate incidents to give systems optimum uptime. They help reduce the MTTR without the need for human intervention. 

Some platforms that offer exceptional  Automated IR tools include:

• ManageEngine
• SumoLogic
• LogRhythm

c. Configuration Management tools

SRE makes use of configuration management tools to track changes made to the settings of the infrastructure. They provide visibility into configuration statuses and, through automation, aid configuration streamlining and recovery. 

Examples of configuration management tools include:

• Puppet
• Chef
• Terraform

d. Container Orchestration tools

Containers are virtualized packages that possess all the backend elements needed for an application to work, regardless of its deployment environment. They contain code, libraries, frameworks, and the necessary runtime environment. 

Container orchestration tools automate the deployment, monitoring, scaling, and overall management of container resources. 

A good example of a container orchestration tool is Kubernetes.

Also Read: What is containerization

It’s also important to understand the clear cut difference between containerization and virtualization

ii. Tools used in DevOps

The tools that DevOps utilize in hastening development processes include:

a. Integrated Development Environments (IDEs)

IDEs allow development teams to write and test codes efficiently. Presented through a single UI, they are made up of a code editor, a code compiler, and a code debugger. Some popular IDEs include:

• Visual Studio Code
• Eclipse
• NetBeans

b. Version Control Systems

Version control systems facilitate the management of changes to software programs. They aid the storage and organization of deployed versions to facilitate references and version recovery if needed. 

Version control systems are crucial to achieving properly coordinated, fast-paced change management. 

Some version control systems include:

• GitLab
• GitHub

c. CI/CD tools

Using automation, CI/CD tools combine the continuous integration of code with the continuous delivery of test builds to test environments to hasten feedback and change. 

Some popular platforms that offer CI/CD tools include:

• Jenkins
• Bamboo
• AWS CodePipeline

d. Cloud testing tools

Cloud testing involves simulating the resource usage around developed features and software versions in cloud environments. It is a part of continuous delivery, as cloud testing tools help to simulate traffic and dynamically test user activity loads against cloud resources. 

Some platforms that offer cloud testing tools include:

• Selenium
• Apache JMeter
• Jenkins

e. Monitoring and Reporting tools

DevOps also makes use of APM tools to monitor, record, and analyze the performance of applications and servers in the test environments.

Popular platforms that offer  DevOps APM tools include:

• Nagios
• Splunk
• Datadog
• ManageEngine

Just like with monitoring and reporting tools, SRE and DevOps share certain similarities in the tools used for containerization, tech orchestration, configuration management, communication, and collaboration. Nonetheless, how these tools are used differs.  

3. SRE vs DevOps: Differences in terms of team roles

DevOps and SRE can also be differentiated by the roles of the respective teams within the software product lifecycle.

i. Role of SRE teams

The SRE team plans, creates, tests, monitors, and repairs software systems/infrastructure to ensure the most uptime. 

They analyze data on system performance, manage the risks threatening system health, and take proactive steps in mitigating and remediating system failures in the user-facing production environment. They analyze SLIs and work very closely with the development team to meet SLOs. 

ii. Role of DevOps teams

The DevOps team develops and tests software to deliver features and applications that meet user demands and SLOs. 

They manage the CI/CD pipeline, utilizing automation to identify issues in production/delivery, solve these issues for faster workflows, build features, test applications, and satisfy quality requirements.

4. DevOps vs SRE: Differences in terms of use cases

The difference between SRE and DevOps in use cases here refers to the part of the software product lifecycle that each methodology is more efficient in.

i. DevOps primarily covers pre-release operations

DevOps eliminates silos in the test environment to improve the speed of development and delivery. It integrates operations workflows to test and optimize new features quickly. It also ensures that the required changes and releases are made as fast as possible. 

ii. SRE primarily covers post-release operations

SRE, on the other hand, ensures that post-release operations are efficient. By collecting and analyzing data,  SRE allows you to foresee risks to the production environment.

Through SRE, metrics like traffic, latency, and errors are monitored. The identified problems are relayed to the DevOps team. Meanwhile, SRE will incorporate any necessary infrastructural changes to improve performance. 

Finally, while DevOps involves testing and implementing effective automation in the test environment, SRE is concerned with improving automation in the production environment.  

Conclusion: Which is better, SRE or DevOps?

Ben Treynor constantly identifies the need for the SRE team to work with the development team. Although he pushes for the unilateral adoption of SRE, DevOps is the younger of the two and the more prominent methodology today. 

Nonetheless, it doesn’t have to be a case of DevOps vs SRE — you don’t have to abandon SRE for DevOps and vice versa. 

Instead, you want to create a collaborative DevOps SRE environment that unifies operations across test and production environments.