DNS tests allow you to proactively monitor the resolvability and lookup times of your DNS records using any nameserver. If resolution is unexpectedly slow or a DNS server answers with unexpected A, AAAA, CNAME, TXT, or MX entries, Datadog sends you an alert with details on the failure, allowing you to quickly pinpoint the root cause of the issue and fix it.
DNS tests can run from both managed and private locations depending on your preference for running the test from outside or inside your network. DNS tests can run on a schedule, on-demand, or directly within your CI/CD pipelines.
After choosing to create a DNS test, define your test’s request.
www.example.com.8.8.8.8, with a fallback on 1.1.1.1 and an internal AWS DNS server.env Tags as well as any other tag to your DNS test. You can then use these tags to quickly filter through your Synthetic tests on the Synthetic Monitoring homepage.Click Test URL to try out the request configuration. A response preview is displayed on the right side of your screen.
Assertions define what an expected test result is. After you click Test URL, basic assertions on response time and available records are added. You must define at least one assertion for your test to monitor.
| Type | Record type | Operator | Value type |
|---|---|---|---|
| response time | is less than | Integer (ms) | |
| every available record | of type A, of type AAAA, of type CNAME, of type MX, of type NS, of type TXT | is, contains,matches, does not match | String Regex |
| at least one record | of type A, of type AAAA, of type CNAME, of type MX, of type NS, of type TXT | is, contains,matches, does not match | String Regex |
You can create up to 20 assertions per API test by clicking New Assertion or by clicking directly on the response preview:
To perform OR logic in an assertion, use the matches regex comparator to define a regex with multiple expected values for the same assertion type like (0|100). The test result is successful if every available record or at least one record assertions’ value is 0 or 100.
If a test does not contain an assertion on the response body, the body payload drops and returns an associated response time for the request within the timeout limit set by the Synthetics Worker.
If a test contains an assertion on the response body and the timeout limit is reached, an Assertions on the body/response cannot be run beyond this limit error appears.
Select the Locations to run your DNS test from: DNS tests can run from managed and private locations depending on whether you are willing to monitor a public or a private domain.
DNS tests can run:
Set alert conditions to determine the circumstances under which you want a test to fail and trigger an alert.
When you set the alert conditions to: An alert is triggered if your test fails for X minutes from any n of N locations, an alert is triggered only if these two conditions are true:
Your test can trigger retries X times after Y ms in case of a failed test result. Customize the retry interval to suit your alerting sensibility.
Location uptime is computed on a per-evaluation basis (whether the last test result before evaluation was up or down). The total uptime is computed based on the configured alert conditions. Notifications sent are based on the total uptime.
A notification is sent by your test based on the alerting conditions previously defined. Use this section to define how and what message to send to your teams.
Similar to how you configure monitors, select users and/or services that should receive notifications either by adding a @notification to the message or by searching for team members and connected integrations with the drop-down box.
Enter the notification message for your test. This field allows standard Markdown formatting and supports the following conditional variables:
| Conditional Variable | Description |
|---|---|
{{#is_alert}} | Show when the test alerts. |
{{^is_alert}} | Show unless the test alerts. |
{{#is_recovery}} | Show when the test recovers from an alert. |
{{^is_recovery}} | Show unless the test recovers from an alert. |
{{#is_renotify}} | Show when the monitor renotifies. |
{{^is_renotify}} | Show unless the monitor renotifies. |
{{#is_priority}} | Show when the monitor matches priority (P1 to P5). |
{{^is_priority}} | Show unless the monitor matches priority (P1 to P5). |
Specify how often you want your test to re-send the notification message in case of test failure. To prevent renotification on failing tests, leave the option as Never renotify if the monitor has not been resolved.
Click on Save to save your test and have Datadog start executing it.
You can create local variables by clicking Create Local Variable at the top right hand corner of your test configuration form. You can define their values from one of the below available builtins:
{{ numeric(n) }}n digits.{{ alphabetic(n) }}n letters.{{ alphanumeric(n) }}n characters.{{ date(n, format) }}n days.{{ timestamp(n, unit) }}n chosen unit.You can use the global variables defined in the Settings in the URL, advanced options, and assertions of your HTTP tests.
To display your list of variables, type {{ in your desired field:
A test is considered FAILED if it does not satisfy one or more assertions or if the request prematurely failed. In some cases, the test can fail without testing the assertions against the endpoint.
These reasons include the following:
CONNRESETDNSINVALID_REQUESTTIMEOUTTIMEOUT can happen:TIMEOUT: The request couldn’t be completed in a reasonable time. indicates that the request duration hit the test defined timeout (default is set to 60s).
For each request only the completed stages for the request are displayed in the network waterfall. For example, in the case of Total response time only being displayed, the timeout occurred during the DNS resolution.TIMEOUT: Overall test execution couldn't be completed in a reasonable time. indicates that the test duration (request + assertions) hits the maximum duration (60.5s).By default, only users with the Datadog Admin and Datadog Standard roles can create, edit, and delete Synthetic DNS tests. To get create, edit, and delete access to Synthetic DNS tests, upgrade your user to one of those two default roles.
If you are using the custom role feature, add your user to any custom role that includes synthetics_read and synthetics_write permissions.
Access restriction is available for customers using custom roles on their accounts.
You can restrict access to a DNS test based on the roles in your organization. When creating a DNS test, choose which roles (in addition to your user) can read and write your test.
Additional helpful documentation, links, and articles:
