Created on 2021-03-11 06:22
Published on 2021-03-11 06:30
This is the second article in a series about SRE Concepts/Topics. In this article, I will discuss two topics that are needed in the next articles. They are SLI and SLO. We will not be going into an SLA.
There are two things related to risk assessment that every Site Reliability Engineer must know: Service Level Indicators and Service Level objectives. Service Level Indicators, also called SLIs, are vital in assessing the risk of an action.
They tell us the performance of a service level of a provider. Without the SLIs, the SRE model will be just as slow as a regular model.
SLIs are the most primary components of a Service Level Agreement. All Service Level Agreements are formed with Service Level Objectives, which are composed of Service Level Indicators.
This risk assessment and performance metric is also called "the real numbers on your performance." Even though you need some knowledge to understand a Service Level Indicator, they give you the most information.
Service Level Indicators are pretty much the real indicators of a metric. For instance, let us say that your Service Level Agreement states that the uptime is 99.91%. It means that the uptime cannot be lower than 99.91%. The Service Level Indicator, in this case, would be either 99.92%, 99.93%, etc.
In other words, a Service Level Indicator should be more than or equal to the agreed-upon value in the Service Level Agreement.
Just like any other indicator, the Service Level Indicator has its challenges. For starters, choosing the right metric is the biggest and the most crucial problem. Selecting the wrong metric can lead to a very confusing agreement and may lead to a potential disaster.
The important thing when it comes to Service Level Indicators is tracking the right number of indicators. Usually, organizations only track the essential metrics. The more the metrics you are tracking, the more your IT department has to work.
Service Level Indicators are already as complicated they can be. Tracking more metrics can further complicate things and make the indicator potentially unreadable. It would be best if you avoid this at all costs.
As we've mentioned earlier, Service Level Indicators are the building blocks of Service Level Objectives. Any company or firm measuring its performance with Service Level Objectives will and must use SLIs.
If Service Level Objectives are the goals for a product, Service Level Indicators measure how well a product did with respect to its goals. If your goal is to maintain an uptime of 99.5%, but your SLI shows a total of 99.9% uptime, then the product exceeded the expectations.
Instead of focussing on tracking more SLIs, SREs should monitor core Service Level Indicators more effectively. One of the primary use cases of SLIs is to build an error budget. If you exceeded the goal, you can refer to the Service Level Indicators and develop a plan to add more features or plan maintenance services.
Service Level Indicators are the best way to measure the performance of a product. Monitoring Service Level Indicators along with SLOs can make your products much more available.
A service level objective is one of the critical aspects of Site Reliability Engineering. Service level objectives help you make necessary commitments and identify the error budget.
Many companies with Site reliability Engineers use service level objectives as one of the key performance indicators.
Unlike service level indicators, service level objectives do not give the value of a specific parameter at an instant of time. They remain constant throughout the agreement. Usually, service level objectives are set before the product is launched and are the building blocks of any service level agreement.
Service level objectives are agreements upon specific metrics. They are present inside a service level agreement and usually represent a measure such as uptime or failure. You can think of SLAs as a formal agreement and service level objectives individual promises inside the agreement.
If you do not satisfy the promise mentioned in the agreement, your product may fail to meet customer requirements and may even lead to significant fines. Understanding service level objectives are quite crucial for a Site Reliability Engineer.
Service level objectives also tell the developer and operations teams their goals for a given product.
Service level objectives also have many challenges like any other metric. One of the main challenges is to make the service level objectives as clear as possible. However, making them overly complicated also creates numerous issues.
If the service level objectives are too vague, it may create confusion on what the goal is. If it is too complicated, the engineers may misinterpret the goals.
A simple rule of thumb is that only the most important metrics should be in the service level objectives. Putting every metric in the service level objectives can create a ton of headaches for your engineers.
The service level objectives should always account for client-side delays, just like service level agreements. SLOs should be spelled out in simple language that both the client and the engineers can understand.
The advantage of service level objectives is that they are useful for both paying and non-paying customers. You can use service level objectives to measure both internal and external customers. The numerous applications make service level objectives one of the primary aspects of the job of an SRE.
The SLOs are simple goals a product must meet. For instance, if the service level agreement states that the uptime should be more than 99.95%, then that is the service level objective for that product. Similarly, you can have service level objectives for many such metrics.
The service level objectives are the key in determining which metrics a developer should consider when changing an application. Sometimes, adding new features may cause downtime. If the service level objective needs more uptime than what the downtime would result in, the upgrades cannot happen.
Service level objectives are the key to success and both customer and team satisfaction. Ensure that you only consider the critical metrics for service level objectives.