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Chapter 2:

Site Reliability Engineering vs DevOps

March 8, 2024
12 min

Modern software delivery rests on two crucial pillars: absolute reliability and lightning-fast agility. The limitations of siloed development and reactive operations mean these approaches can no longer support the modern, dynamic IT landscape. SRE and DevOps have evolved to offer distinct approaches to removing these complexities.

SRE came from the need for highly reliable services due to Google’s massive scale. DevOps arose from the frustration of slow, traditional software development methods.

In this article, we discover how SRE and DevOps differ, where they overlap, and how they address the challenges of modern application delivery.

SRE vs DevOps: How do they differ?

While both SRE and DevOps play crucial roles in modern software development, they approach various challenges from distinct perspectives. Here’s a table that summarizes their key differences.

Area SRE DevOps
Core philosophy and focus An engineering-driven approach prioritizing system reliability and stability A cultural shift emphasizing collaboration and efficiency in software development
Key practice Implementing automated solutions for operational challenges and reliability engineering Integrating continuous integration and delivery with infrastructure automation
Workflow and process Focuses on proactive system monitoring, incident management, and post-incident analysis Centers on streamlining the development, testing, and deployment cycle
Metrics and KPIs Tracks SLOs, error budgets, and MTTR Measures deployment frequency, change failure rate, and lead time for changes

The birth, journey, and philosophies at the core of SRE and DevOps

The development of SRE

Google’s production environment dwarfs most others in terms of scale and intricacy. Behind the scenes of Google’s familiar apps like Gmail and Maps lies an extensive IT infrastructure ecosystem. Site reliability engineering (SRE) emerged as a solution to ensure reliability, scalability, and efficiency in managing Google’s giga-scale operations.

Finding no other third-party tools of use, Google’s platform engineers—with their deep understanding of Google’s production complexities—engaged in designing a framework and developing the tools they needed to keep its massive infrastructure engine running smoothly. These tools, ranging from binary rollout mechanisms to monitoring systems and dynamic server composition environments, were managed as full-fledged engineering projects instead of being just treated as quick fixes. 

Dickerson’s hierarchy of site reliability (source)

Today, SRE is a widely recognized practice by organizations of all sizes. Although the scope of SRE has expanded significantly over the years to include infrastructure design, capacity planning, and performance optimization, the need for speed and continuous improvement in software delivery led to the initial rise of DevOps. 

The creation of DevOps

Despite the adoption of agile practices, development and operations remained siloed for years. DevOps emerged as the next step, aiming to bridge this gap and foster collaboration to deliver better software faster.

Born from the concerns of IT operations and software development communities about the inefficiencies of the traditional model, DevOps emphasizes breaking down silos and bringing these teams together. This collaborative approach fosters:

  • Shared ownership: Developers and operations personnel work together throughout the entire development lifecycle, from planning and coding to deployment and maintenance.
  • Continuous integration and delivery (CI/CD): Automating code merging, testing, and deployment processes streamlines releases and reduces errors.
  • Infrastructure as code (IaC): Treating infrastructure as code enables consistent and repeatable deployments, minimizing manual configuration errors.
  • Monitoring and feedback: The continuous monitoring of deployed applications provides valuable insights for further improvement and iteration.


SRE vs. DevOps: distinct philosophies

While SRE and DevOps share common ground in terms of automation and efficiency improvement, their core philosophies diverge:

  • SRE prioritizes reliability above all else, employing cautious rollouts and prioritizing system stability.
  • DevOps emphasizes speed and agility, favoring smaller, more frequent deployments to deliver value faster.

Key practices of SRE and DevOps

SRE and DevOps share a common ground in automation and continuous improvement, but their practices diverge in focus.

SRE: building reliable and efficient systems through proactive engineering

SRE’s practices contribute to system stability and efficiency by leveraging a framework where operational tasks are automated, incidents are managed systematically, and reliability is engineered into every aspect of the system.

SRE emphasizes building reliability from the ground up, employing techniques like chaos engineering and failure injection to identify and address potential issues before they impact production. This proactive approach prevents costly outages and ensures smooth operation.

SREs role in ensuring system resilience through redundancy and failover

The following table summarizes SRE practices and their purposes and benefits.

SRE Practice Purpose Benefits
Reliability engineering Proactive planning and design ensure that systems are resilient, withstand unexpected events, and deliver consistent performance. This includes redundancy, failover mechanisms, and capacity planning. Fewer outages and faster resolution times lead to an improved user experience and better business continuity.
Incident management Structured processes for identifying and resolving incidents minimize downtime and impact on users. Root cause analysis helps prevent future occurrences. Automation frees up time for engineers to focus on strategic initiatives and innovation.
Automation of operational tasks Repetitive tasks like monitoring, configuration management, and deployments are automated, freeing human resources for higher-level work while reducing manual errors. Metrics collected from monitoring and incident response inform system optimization and resource allocation.

DevOps: streamlining application delivery through collaboration and automation

DevOps practices enhance collaboration and streamline the entire software development lifecycle. Its practices bring agility and speed to software delivery, ensuring quality and reducing time-to-market.

DevOps Practice Description Benefits
Continuous integration (CI) Code changes are automatically built, tested, and merged frequently into the main codebase. CI leads to early detection and resolution of integration issues and improved software quality.
Continuous delivery (CD) Automated deployments of code changes to production environments occur rapidly and reliably. CD enables faster release cycles, shorter feedback loops, and reliable deployments.
Infrastructure as code (IaC) Infrastructure configurations are defined and managed as code, allowing for consistent, automated provisioning and deployment. Consistent, automated provisioning, less manual effort, and reduced incidence of human error.

Behind the scenes: workflow and process dynamics

Automation is always at the core. Through SRE, you automate away repetitive, manual tasks such as vulnerability assessment or infrastructure provisioning, allowing engineers to focus on higher-value activities that contribute directly to the system’s reliability. With DevOps, automation enables rapid development cycles, ensuring that new features and fixes are deployed quickly and efficiently without sacrificing quality.

That said, despite the shared emphasis on automation for both practices, a deeper look reveals distinct approaches to managing workflows, handling incidents, and deploying software.

Workflow and process dynamics

As an SRE architect, the first step is to embrace a mindset where reliability is measured in the context of system architecture. You give greater importance to designing systems that are inherently resilient, capable of anticipating failures, and self-healing. This approach requires a deep integration of monitoring and alerting systems that can predict and mitigate issues before they escalate, ensuring that reliability metrics are always within defined service-level objectives (SLOs).

On the flip side, a DevOps workflow focuses on fostering a culture of collaboration and rapid iteration within your team. It emphasizes the need for architects to design systems that support continuous integration and continuous delivery (CI/CD), allowing for the seamless flow of code from development to production. This includes implementing automated testing and deployment pipelines that reduce manual toil and minimize the risk of errors. 

A DevOps software delivery lifecycle

Incident response: structured vs. agile approach

SRE emphasizes a structured, proactive approach to incident response. A continuous focus on monitoring systems to predict and mitigate issues before they escalate minimizes the likelihood of disruptions. However, no system is foolproof, and incidents can still occur. In such cases, the structured approach essentially ensures that there’s a predefined protocol to help with systematic resolution.

Conversely, DevOps emphasizes agility in incident response by championing a collaborative effort. The focus is always on rapid identification, communication, and resolution through cross-functional expertise. This agility allows DevOps teams to adapt quickly to issues, ensuring that continuous delivery and integration are not impacted.

Deployment strategies: reliability vs. speed

To prioritize reliability above all else, it is common to employ canary releases and blue-green deployment strategies in SRE. These strategies allow for controlled rollouts, enabling SRE teams to gradually introduce changes to a small subset of users or infrastructure at first. A phased approach facilitates close monitoring of the impact on system performance and user experience. If any unforeseen issues arise, SRE teams have the flexibility to roll back changes quickly, minimizing disruption and safeguarding the user experience.

DevOps thrives on a culture of continuous delivery and rapid iteration, helping you constantly push new features and fixes to users at an accelerated pace. Streamlining the entire software development lifecycle, from code commit to deployment, requires a seamless interplay among three key techniques:

  • Automated pipelines streamline the delivery of code changes while eliminating manual intervention and reducing the risk of errors.
  • Feature flags allow for the gradual rollouts of new features to a subset of users for testing and feedback before wider deployment. If issues arise, the feature can be disabled quickly to ensure minimal disruption.
  • Rolling updates minimize downtime and ensures that a portion of the system remains functional even during updates.

Measuring success through critical metrics and KPIs

To truly unlock the potential of DevOps and SRE, consider shifting your focus to impactful delivery. It is important to see how quickly you push features, identify and fix issues, and, ultimately, serve your users. This means going beyond the numbers and diving deeper into the user experience, team dynamics, and continuous optimization.

In other words, quantifying actions is just the first step. The true answer lies in understanding how these actions translate into meaningful outcomes for your users and business.

Since SRE and DevOps prioritize different aspects of software health, tracking the metrics of both practices together is often a more pragmatic approach. With this broader perspective, you can identify correlations, optimize workflows, and ultimately unlock the true potential of both practices to enable impactful delivery.

How SRE metrics ensure system reliability

SRE metrics focus on stability, performance, and resilience. Collectively, these metrics can potentially highlight your system’s ability to withstand stress and deliver a seamless experience under varying conditions.

Goal Purpose Metrics to track
Identify and fix issues early Detect performance problems and stability risks before they impact users. Latency: System response time
Error rates: Frequency of errors encountered by users or applications
Traffic: Demand placed on the system (e.g., users per second)
Quantify the impact of changes Measure the effect of deployments, configuration adjustments, and other changes on system behavior. Change failure rate: Frequency of deployments causing new issues (new bugs introduced by a release)
Resource utilization: CPU, memory, and storage load across the infrastructure
Incident response time: Time taken to identify and address incidents
Optimize performance Ensure efficient resource utilization and the smooth handling of user demand. System uptime: Percentage of time your system is operational
Resource contention: Identification of overloaded components in your infrastructure
Application response time distribution: Analysis of different response time ranges for user requests

Measuring DevOps metrics for continuous improvement

DevOps metrics focus on speed, efficiency, and quality. They provide insights into how quickly you’re innovating, how efficiently you’re developing, and how effectively you’re delivering high-quality features.

A low deployment frequency might hint at a fear of deployment, suggesting a lack of confidence in your testing or release processes. Conversely, optimizing your lead time for changes can significantly enhance your market responsiveness, allowing you to roll out features or fixes ahead of competitors.

Goal Purpose Metrics to track
Identify and remove bottlenecks Find “points of lethargy” in the development pipeline to streamline processes and accelerate releases. Deployment frequency: How often you release new features
Lead time for changes: Time from code commit to production
Mean time to recovery (MTTR): How quickly you recover from incidents
Measure automation impact Track the impact of automated testing and deployment on speed and quality. Percentage of automated tests: Coverage of your codebase by automated tests
Deployment success rate: Frequency of successful deployments without issues
Defect escape rate: Number of bugs slipping through testing
Promote continuous improvement Use data to guide your team toward efficient development practices. Pull-request merge time: Time from submitting to merging code changes
Code coverage: Percentage of code covered by automated tests
Code churn: Frequency of code changes within a short period
Align with business goals Discover how faster releases and improved quality contribute to achieving objectives. Time to market: Time from conception to release
Customer satisfaction (CSAT) score: Feedback on release impact and value
Number of resolved user issues: Effectiveness of development efforts


Mastering both SRE and DevOps

As an enterprise architect, your role typically involves not just choosing between SRE and DevOps but often blending these methodologies to suit your organization’s specific needs. This could mean adopting SRE principles for parts of your infrastructure that require high reliability while implementing DevOps practices to enhance agility and speed in feature development and deployment. 

At Squadcast, we understand the complexities of juggling SRE and DevOps practices within a single workflow. Siloed tools, fragmented communication, and manual processes can hinder efficiency and reliability. That’s why we’ve developed a full-stack, unified reliability automation platform designed to bridge the gap between these two crucial disciplines.

To learn more about Squadcast’s full-stack, unified reliability automation platform, start a free trial here.

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Squadcast is a leader in Incident Management on G2 Squadcast is a leader in Mid-Market IT Service Management (ITSM) Tools on G2 Squadcast is a leader in Americas IT Alerting on G2
Best IT Management Products 2024 Squadcast is a leader in Europe IT Alerting on G2 Squadcast is a leader in Enterprise Incident Management on G2
Users love Squadcast on G2
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