Advanced DNS Synthetic Monitor

• Log into the F5® Distributed Cloud Console.

• Navigate to either the Observability workspace tile or menu.

Note: The homepage is role based, and your homepage may look different due to your role customization. Select All Services drop-down menu to discover all options.

Figure: Observability Tile

Figure: Observability Menu

• Select Manage > Synthetic Monitors > DNS Monitors.

Figure: Manage Menu

• Click Add DNS Monitor.

• Enter Name, Labels, and Description as needed.

Figure: Metadata

• Enter the Domain that you would like to monitor.

• Select the Record Type of the domain you would like to monitor.

• Set the monitor frequency Interval for how often you would like the monitor to run from each source region configured later in the form.

• Adjust the protocol if you are not using UDP.

Figure: What to Monitor

Note: Each source provider and region added will monitor the endpoint configured for the monitor. The combined health from all regions will generate the overall monitors global health.

• In the Sources section, click Add Item to begin adding sources for the monitor.

Figure: Empty Sources

• Select the desired Provider for which you would like to source the monitor from.

• With the Provider selected, click the Regions dropdown and select which Region you would like the monitor run from.

• Select additional regions from the dropdown if you would like to add more Regions for the current Provider.

Figure: Provider Regions

• Click Apply to add the current Provider and Regions to the monitor.

• Back in the primary Sources section, select Add Item and follow the steps above if you would like to add additional Providers and Regions.

Figure: Sources

Note: Custom nameservers are optional, and the monitor will use its default nameservers for validation by default. Each configured Region will monitor each nameserver configured here.

• Click Add Item on Custom Name Servers to add a specific nameserver you would like checked by the monitor.

Figure: Add Nameserver

• Fill in the Name Server IP and Port to match your desired DNS infrastructure. You can click Add Item again if you require additional nameservers.

Figure: Added Nameservers

• Update the Query Timeout (ms) to control how long the monitor waits for a response before becoming critical.

• Update the Number of consecutive test failures to control how many failed monitors must happen in a row before becoming Critical.

• Update the Number of Nameservers to control if ANY or ALL nameservers tested must pass to be considered Healthy.

• Update the Number of Failed Locations to control how many regions must fail before the global monitor becomes Critical.

Figure: Completed How to Monitor

• Optionally, enable Health Policy to set a dynamic and/or static threshold when determining the health.

  • When a dynamic threshold is enabled, a rolling average of the last 7 days of response time data will be analyzed to dynamically set a response time threshold. If that threshold is exceeded for a period greater than the defined evaluation period, the monitor health will turn critical. A higher standard deviation value will generate fewer alerts, while a lower standard deviation value will generate more alerts.
  • When a static maximum threshold is enabled, monitor health will turn critical if the defined max response time is exceeded for a period greater than the defined evaluation period.
  • When a static minimum threshold is enabled, monitor health will turn critical if the response time is lower than the defined min response time for a period greater than the defined evaluation period.

Figure: Setting health policy

• Select Save and Exit to save the new DNS Synthetic Monitor.

• Alerting for Synthetic Monitoring can be configured similar to other F5® Distributed Cloud services following the Alerting how-to guide.

• Optionally filter your Alert Policy to only send notifications to the receiver based on alerts coming from Synthetic Monitoring by either matching the Group to Synthetic-Monitors or matching the Alert Name to SyntheticMonitorHealthCritical

Figure: Alerting