Introduction
As more and more organizations embrace cloud-based computing and the web of digital services expands, Site Reliability Engineering (SRE) practices have become essential.
These practices use software technology and engineering to automate IT operations such as production system management, change management, incident response action and emergency response action. These would have otherwise been handled by human administrators.
SRE engineers endeavor to improve the operating software while minimizing the work involved in its upkeep. They focus on automating as many tasks as possible so that operations’ experts can shift their attention to providing strategic, higher-level work, such as planning a new deployment or creating a faster pipeline for product feedback.
SRE is a valuable practice when creating scalable and highly reliable software systems. It helps manage large systems through code, which is more scalable and sustainable than for system administrators managing hundreds of machines.
What are the Key Principles of SRE ?
SRE has the following key principles:
Application Monitoring: It is almost certain that some errors will occur during the course of the software development process. Thus application monitoring becomes very important. Performance indicators are checked using service-level agreements (SLAs), service-level indicators (SLIs), and service-level objectives (SLOs), discussed later.
Gradual Change Implementation: This is another key principle of SRE – to avoid large corrections, many small developments and improvements are released frequently.
Automation for Reliability Improvement: SRE advocates strategies such as automation to resolve problems and improve reliability by:
- Setting-up quality gates based on service-level objectives to detect issues earlier
- Automating build-testing using service-level indicators
- Making strategic architectural decisions that ensure system resiliency at the early stages
Observability in SRE
This is the process inculcated in the teams and systems so that they can handle any uncertainties that may arise when the software goes live. Some of the tools used for this are:
Metrics: These are quantifiable values that reflect an application’s performance or the system’s health. Teams use metrics to determine if the software consumes excessively high resources or behaves abnormally
Logs: Usually automated, these time-stamped reports help software engineers to understand the chain of events that lead to a particular problem.
Traces: These are the path trajectories followed by digital objects. For example, checking a shopping cart might involve the following:
- Tallying the price with the database
- Authenticating the payment with the gateway
- Submitting the correct order to the vendor
Monitoring in SRE
This is the process of paying attention to specific critical parameters of the system that reflect its health and performance. One may pay significant attention to the following:
Latency: This refers to the delay in the response when an action on an application is instigated. This tells you about the speed of the system
Traffic: This measures the number of users concurrently accessing the application. It helps in the appropriate allocation of power and computing resources per system
Errors: These are the perplexing situations where application features do not perform according to expectations. SRE teams are required to investigate and fix these
Saturation: This parameter indicates the capacity of the system to take load. A high level of saturation usually degrades the performance, so an SRE engineer must monitor the load to keep it below a specific threshold.
Service Performance Metrics in SRE
Service-Level Objectives: These are specific and tangible goals that one is confident about, about the performance of their application. For example:
- Uptime, or the time a system is available for use
- System throughput, i.e. how many units of input it can handle at given time
- System output
- Download rate, or the speed at which the application loads
Service-Level Indicators: These are the actual test measurements of the metrics defined in Service-Level Objectives, and are expected and required to be as close as possible to them
Service-Level Agreements: These are legal documents that state what would happen when one or more SLOs are not met. You might be obligated to refund a customer, if unable to resolve the issue
Final Conclusion
SRE is basically a job function, a mindset, and a set of engineering practices to run reliable production systems. As a discipline, it focuses on improving software system reliability across key categories including availability, performance, latency, efficiency, capacity, and incident response.
As the tech world blooms, IT teams are constantly looking to adopt SRE methodologies. SRE is slowly taking over tasks historically done manually by operations teams, and giving many of them to engineers who are utilizing software and automation to make them more reliable, effective and futuristic.