In one of our previous articles, we discussed what an SRE is, what they do, and some of the common responsibilities that a typical SRE may have, like supporting operations, dealing with trouble tickets and incident response, and general system monitoring and observability. In this article, we will take a deeper dive into the various SRE principles and guidelines that a site reliability engineer practices in their role. Like DevOps, these SRE principles serve as a guide to drive alignment as it relates to aligning, meeting, and supporting the goals of the organization.
Google was the first company to create, embrace, and put support behind the role of site reliability engineering. Since that time, the SRE role has evolved as the industry has changed and shifted from the traditional monolithic structures to large, widely distributed networks and microservices. However, one thing has largely remained the same – the principles by which SREs adhere to. These core SRE principles are focused on one thing: driving system and service reliability. Let us take a deeper dive into these core SRE principles.
SRE Principles
Embracing and Managing Risk
Embracing risk is actually one of the core principles of SRE, and it’s easy to see why. To make a system more reliable, you have to consider “what if” scenarios and learn from potential failures. No system is ever 100% reliable and at some point, something’s bound to go wrong. Unfortunately, most users don’t know (or particularly care) about this reality. They just want things to work, and there’s always a cost to achieving that reliability, whether in money, time, or even in maintaining customer trust.
For SREs, leaning into risk and learning from failure are essential to building resilient systems. But there are always trade-offs to weigh. Maximizing reliability might mean slowing down the pace of new features, or it could lead to more costs without much boost in revenue. The idea isn’t to make a system more reliable than it actually needs to be. After all, if the extra effort and resources don’t add meaningful value, they’re better spent elsewhere. In SRE, it’s all about finding that “just right” level of reliability that balances cost, speed, and value.
Service Level Objectives
The principle of embracing risk is closely tied to Service Level Objectives (SLOs). To break it down, SLOs are specific performance goals within a Service Level Agreement (SLA) which are measured against Service Level Indicators (SLIs), the actual metrics that track how your service is performing. For example, if your SLO states that uptime should be 99.9%, the SLI measures whether you’re hitting that mark. These SLIs are continuously monitored by SREs, so if performance dips below the agreed threshold, the team is alerted and can respond quickly. SLIs are ultimately about what matters most to users, helping teams prioritize service aspects that directly impact the user experience.
Here’s a quick breakdown of these terms:
- SLAs: The overall agreements with clients or customers about the level of service to be delivered.
- SLOs: Specific performance goals within the SLA, like uptime, response time, or security standards.
- SLIs: The actual performance measurements that track compliance with the SLOs.
In essence, SLOs allow teams to measure real performance against the SLA, setting clear expectations about service quality. This structure reinforces that there’s an agreed tolerance for risk, defining just how much variability or downtime a service can sustain while still meeting user needs and business goals.
Read: Learn more about managing SLA compliance within your organization.
Eliminate Toil
Toil, as it is defined with the scope of the SRE role, is the amount of manual work that is required to ensure services are running. One of the main goals of an SRE is to automate as much work as possible. This allows SREs to open up more time for more important tasks. And when you think about it, reducing toil should really be a part of anyone’s job. The less time needed on redundant tasks is ensures better productivity in the long run. Any time a site reliability engineer must engage in repetitive manual activities, as it relates to managing the production service, this can be described as toil.
In a lot of instances, there may be occasions where an SRE has to carry out manual, time-consuming activities, but not all of them should be defined as toil. However, it is key to define which activities within the SRE team are consuming the most time. From there, identify where improvements can be made to reduce the amount of toil for better work balance. When Google first introduced the role of SRE, they set a goal that half of an SREs time should be focused on reducing future operational work or adding service features. Developing new features correlates with improving metrics like reliability and performance, which ultimately reduces potential toil down the line.
Monitoring
At Dotcom-Monitor, we are all about monitoring solutions for tracking uptime, availability, functionality, and all-around performance of servers, websites, services, and applications. Monitoring is one of the most important SRE principles within the role. Continuous monitoring ensures that services are performing as intended and can help identify the moment issues arise so they can be fixed immediately. Like we mentioned in the previous section, meeting those SLOs are key to the defined business SLAs, and ultimately, users. Monitoring can provide SREs and teams with a historical trend of performance and can offer insight to what is a one-off issue versus a wider, systemic problem. As defined by the Google SRE initiative, the four golden signals of monitoring include the following metrics:
- Latency. Latency is the amount of time, or delay, a service takes to respond to a request. Clearly, slow response times will affect the perceived user experience. Monitoring can provide a way to differentiate between
- Traffic. Traffic refers to the amount of user demand, or load, is on the system. This can be measured by HTTP requests per second or depending on the actual service
- Errors. Errors refer to the rate at which requests to the service fail. However, it is important for SRE teams to differentiate between hard failures, like 500 server errors, and soft failures, such as a 200 OK response that timed out because a specific performance threshold was set. It is important to consider how to appropriately monitor these different scenarios like these.
- Saturation. Saturation is about measuring how much system resources a given service has. Up to a certain point, most services will experience performance degradation. Understanding where this occurs can help correctly define monitoring objectives and targets, so corrective action can be carried out.
Automation
Automate, automate, automate. We touched on this principle earlier when we discussed reducing toil, but it cannot be understated. The nature of the SRE role is as diverse as a role can be. In order to reduce the potential for manual intervention across all facets of their responsibilities, automating tasks is key to a successful business. As services scale and become more distributed, it becomes much harder to manage. Automating repetitive tasks across the board, whether it is testing, software deployment, incident response, or simply communication between teams, automating provides immediate benefits, efficiencies, and most importantly, consistency. Since the time the SRE role was conceived, there has been a shift in how development, QA, and Operations teams collaborate. To support these new DevOps environment and practices, various platforms and tools have been developed.
Read: Top 13 Site Reliability (SRE) Tools.
Release Engineering
Release engineering. Sounds like a complex subject, but in reality, it is just a simple way to define how software is built and delivered. While release engineering in itself is its own title and role, within the concept of SRE, this means delivering services that are stable, consistent, and of course, repeatable. This goes back to the previous section about automation. If you are going to do something, do it right AND be able to repeat that again, in a consistent manner, as necessary. Building a bunch of one-off services is time-consuming and creates unneeded toil.
If we go back to the history of the SRE position at Google, they had dedicated release engineers who worked directly with SREs. Release engineers are typically tasked with defining best practices as it relates to developing software services, deploying updates, continuous testing, and addressing software issues, in addition to many other responsibilities. This role becomes more critical when you think about how to scale services and deploying them quickly. Having a set of best practices and tools (and enforcing them) is essential to being able to meet these demands and gives peace of mind to SRE teams once that build is put into production.
Simplicity
With a position that has seemingly no end to the number of responsibilities and expectations like the SRE role has, the last principle, ironically, is simplicity. Maybe easier said than done in practice, this principle focuses on the idea of developing a system or service that is only as complex as necessary. While that may seem counterintuitive at first, it really boils down to wanting a system that is reliable, consistent, and predictable. That may sound boring, but to an SRE, that is one of the ultimate end goals.
SREs strive for a system or service that is not complex or difficult to manage. SREs want one that simply does the job that it was designed to do. However, from a user’s perspective, a service that provides a lot of features may also provide a lot of benefits, but to a SRE, that just means more potential headaches. However, change is always inevitable if you want to add new features to a web service, do so thoughtfully. Smaller, incremental changes are easier (and simpler) to manage than building out and shipping a lot of features at one time. SREs also has to consider the needs and goals of the business as well.
SRE Principles: The 7 Fundamental Rules – Final Thoughts
The SRE role focuses on building, delivering, and maintaining reliable systems and services at scale. These seven core principles of help define the practices for SREs that help drive alignment within DevOps practices and support the goals of the business. It is a complex role that seeks to balance reliability with feature releases, all while maintaining exceptional levels of quality.
The Dotcom-Monitor platform provides SREs with all the monitoring features they need ensure continuity of their services. From configurable alerts and reports to real-time dashboards and reports, the platform provides the essential tools required to manage performance of all their services for the long-term. For example, create web application scripts based on user behavior, actions, and paths and set up synthetic monitoring tasks to ensure a consistent experience over time. No matter the level of monitoring your team requires, there is a solution to meet your needs.
Get started for free with the Dotcom-Monitor free trial or schedule a demo with one of our performance engineers.
