Service Level Objectives

Service Level Objectives


Overview

Service Level Objectives, or SLOs, are a key part of the site reliability engineering toolkit. SLOs provide a framework for defining clear targets around application performance, which ultimately help teams provide a consistent customer experience, balance feature development with platform stability, and improve communication with internal and external users.

Key terminology

Service Level Indicator (SLI)
A quantitative measurement of a service’s performance or reliability. In Datadog SLOs an SLI is a metric or an aggregation of one or more monitors.
Service Level Objective (SLO)
A target percentage for an SLI over a specific period of time.
Service Level Agreement (SLA)
An explicit or implicit agreement between a client and service provider stipulating the client’s reliability expectations and service provider’s consequences for not meeting them.
Error Budget
The allowed amount of unreliability derived from an SLO’s target percentage (100% - target percentage) that is meant to be invested into product development.

Setup

You can use Datadog’s Service Level Objectives status page to create new SLOs or to view and manage all your existing SLOs. You can also add SLO Summary widgets to your dashboards to visualize your SLO statuses at a glance.

Configuration

  1. On the SLO status page, select New SLO +.
  2. Define the source for your SLOs. SLO types are Metric-based and Monitor-based.
  3. Set up to three SLO targets. Each target consists of a target percentage and a rolling time window. Available time windows are: 7 days, 30 days, and 90 days. It is recommended that you make the SLO target percentage stricter than the target percentages stipulated in your SLAs.
  4. Finally, give the SLO a title, describe it in more detail or add links in the description, add tags, and save it.

After you set up the SLO, select it from the Service Level Objectives list view to open the details side panel. The side panel displays the overall status percentage and remaining error budget for each of the SLO’s targets, as well as status bars (monitor-based SLOs) or bar graphs (metric-based SLOs) of the SLI’s history. If you created a grouped monitor-based SLO using one multi alert monitor or a grouped metric-based SLO using the sum by clause, the status percentage and remaining error budget for each individual group is displayed in addition to the overall status percentage and remaining error budget.

Example: If you create a monitor-based SLO to track latency per availability-zone, the status percentages and remaining error budget for the overall SLO and for each individual availability-zone that the SLO is tracking are displayed.

Note: The remaining error budget is displayed as a percentage and is calculated using the following formula:

Setting SLO targets

To leverage the benefits of error budgets and error budget alerts, you must set SLO target values strictly below 100%.

Setting a 100% target means having an error budget of 0% since error budget is equal to 100%—SLO target. Without error budget representing acceptable risk, you face difficulty finding alignment between the conflicting priorities of maintaining customer-facing reliability and investing in feature development. In addition, SLOs with target values of 100% lead to division by zero errors in SLO alert evaluation.

Note: The number of decimal places you can specify for your SLOs differs depending on the type of SLO and the time windows you choose. Refer to the links below for more information for each respective SLO type.

Monitor-based SLOs: Up to two decimal places are allowed for 7-day and 30-day targets, up to three decimal places are allowed for 90-day targets.

Metric-based SLOs: Up to three decimal places are allowed for all targets.

Edit an SLO

To edit an SLO, hover over the SLO’s row in the list view and click the edit pencil icon that appears at the right of the row, or click on the row to open the details side panel and select the edit button from the cog icon in the top right of the panel.

Searching and viewing SLOs

The Service Level Objectives status page lets you run an advanced search of all SLOs so you can find, view, edit, clone or delete SLOs from the search results.

Advanced search lets you query SLOs by any combination of SLO attributes:

  • name and description - text search
  • time window - 7d, 30d, 90d
  • type - metric, monitor
  • creator
  • tags - datacenter, env, service, team, etc.

To run a search, use the facet checkboxes on the left and the search bar at the top. When you check the boxes, the search bar updates with the equivalent query. Likewise, when you modify the search bar query (or write one from scratch), the checkboxes update to reflect the change. Query results update in real-time as you edit the query; there’s no ‘Search’ button to click.

To edit an individual SLO, hover over it and use the buttons that appear at the right of its row: Edit, Clone, Delete. To see more details on an SLO, click its table row to open its details side panel.

SLO tags

When you create or edit an SLO, you can add tags for filtering on the SLO status page or for creating SLO saved views.

SLO default view

The default SLO view is loaded when you land on the SLO list view.

The default view includes:

  • An empty search query
  • A list of all defined SLOs in your organization
  • A list of available facets in left side facet list

Saved views

Saved views allow you to save and share customized searches in the SLO list view for SLOs that are most relevant for you and your team by sharing:

  • A search query
  • A selected subset of facets

After you query for a subset of SLOs on the list view, you can add that query as a saved view.

Add a saved view

To add a saved view:

  1. Query for your SLOs.
  2. Click Save View + at the top left of the page.
  3. Name your view and save.

Load a saved view

To load a saved view, open the Saved Views panel by pressing the Show Views button at the top left of the page and select a saved view from the list. You can also search for saved views in the Filter Saved Views search box at the top of that same Saved Views panel.

Share a saved view

Hover over a saved view from the list and select the hyperlink icon to copy the link to the saved view to share it with your teammates.

Manage saved views

Once you are using a saved view, you can update it by selecting that saved view, modifying the query, and clicking the Update button below its name in the Saved Views panel. To change the saved view’s name or delete a saved view, hover over its row in the Saved Views panel and click the pencil icon or trash can icon, respectively.

SLO audit events

SLO audit events allow you to track the history of your SLO configurations using the Event Stream. Audit events are added to the Event Stream every time you create, modify or delete an SLO. Each event includes information on an SLO’s configuration, and the stream provides a history of the SLO’s configuration changes over time.

Each event includes the following SLO configuration information:

  • Name
  • Description
  • Target percentages and time windows
  • Datasources (monitor IDs or metric query)

Three types of SLO audit events appear in the Event Stream:

  1. SLO Created events show all four pieces of SLO configuration information at creation time.
  2. SLO Modified events show a what configuration information changed during a modification
  3. SLO Deleted events show all four pieces of configuration information the SLO had right before it was deleted

To get a full list of all SLO audit events, enter the search query tags:audit,slo in the Event Stream. To view the list of audit events for a specific SLO, enter tags:audit,slo_id:<SLO ID> with the ID of the desired SLO.

You can also query the Event Stream programmatically using the Datadog Events API.

Note: If you don’t see events appear in the UI, be sure to set the time frame of the Event Stream to a longer period, for example, the past 7 days.

To proactively manage the configurations of your SLOs, set an Event Monitor to notify you when events corresponding to certain tags occur.

For example, if you wish to be notified when a specific SLO’s configuration is modified, set an Event Monitor to track the text [SLO Modified] over the tags audit,slo_id:<SLO ID>.

SLO widgets

After creating your SLO, you can use the SLO Summary dashboard widget to visualize the status of an SLO along with your dashboard metrics, logs and APM data. For more information about SLO Widgets, see the SLO Widgets documentation page.

SLO status corrections

Status corrections allow you to specify time periods such as planned maintenance that an SLO excludes from its status and error budget calculations.

When you create a correction window for an SLO, the time period you specify is removed from the SLO’s calculation.

  • For monitor-based SLOs, time in the correction window is not counted.
  • For metric-based SLOs, all good and bad events in the correction window are not counted.

Status corrections are in public beta through the SLO status corrections API, Terraform, and the UI.

Access in the UI

To access SLO status corrections in the UI:

  1. Create a new SLO or click on an existing one.
  2. Navigate to an SLO’s detailed side panel view.
  3. Under the gear icon, select Correct Status to access the Status Corrections creation modal.
  4. Select the Time Correction Window, Correction Type, and add Notes.
  5. Click Apply Correction.

To view, edit, and delete existing status corrections, click on the Corrections tab at the top of an SLO’s detailed side panel view.

Further Reading