Configure Failover with a Traffic Controller Pool for a Directional Pool

This article explains how to create Traffic Controller pools first, and then use those pool hostnames as records in a Directional pool.

Use this configuration when Directional DNS should choose the answer based on routing rules, while each Traffic Controller pool manages probing, failover, backup response behavior, and weighted traffic distribution for its own destination.

When to Use This Article

• You want to route users to different destinations using a Directional pool.
• You want each destination to use Traffic Controller health checks and failover behavior.
• You need to create Traffic Controller pools for multiple data centers, regions, or destination groups.
• You want to use Traffic Controller pool hostnames as the answers returned by a Directional pool.

Before You Begin

• Confirm that the domain already exists in UltraDNS.
• Confirm the record type you want to use for the Traffic Controller pools, such as A or AAAA.
• Confirm the destination IP addresses or hostnames that each Traffic Controller pool should contain.
• Confirm which Directional method and group type you need to use, such as Filtering with Geolocation, Source IP, ASN, or ASN + Geolocation, or Steering with Geo Proximity.

Create the Traffic Controller pools before creating the Directional pool. The Traffic Controller pool hostnames are used later as records in the Directional pool.

Create a Traffic Controller Pool

1. Log in to UltraDNS.
2. Click Domains.
3. Click the domain where you want to create the Traffic Controller and Directional pools. For example, ultraexample.com.
4. Locate the record type that will be used for the pool, such as A or AAAA.
5. Click +Add Pool.
6. In Host, enter the hostname for the Traffic Controller pool. For example, dc1.ultraexample.com.
7. In Points To, enter the IP address or hostname for the first destination record.
8. In TTL, enter the desired TTL value, or leave the field empty to use the default value.
9. In Select Pool Type, select Traffic Controller (TC).
10. Click Save.

After the pool is created, the Traffic Controller pool details page appears. The available tabs include Pool Information, Probe Definitions, Scheduled Events, Notifications, and Alerts.

Configure Traffic Controller Pool Information

From the Pool Information tab, review or update the pool-level settings as needed.

• Failover determines whether the pool acts on probe results.
• Backup Method determines how UltraDNS responds when all primary records in the Traffic Controller pool fail health checks.
• Probing determines whether probes are used to check whether pool records can be served. Probing cannot be disabled unless Failover is also disabled.
• Max Active to LB specifies the maximum number of active servers in the pool and determines when Traffic Controller takes backup servers offline.
• TTL specifies the Time to live value for the pool.
• Failure Threshold indicates the minimum number of failed records required for the pool to be labeled failed.

Click Save after making any pool-level changes.

Add Traffic Controller Pool Records

1. In the Records List section, click +Add Record.
2. In Points To, enter the IP address or hostname for the additional pool record.
3. Select the Failover Delay value.
4. Select the Restoration Delay value.
5. Enter an even integer value for Weight. Weight helps determine the traffic load sent to each server in the pool.
6. Select All Fail only if this record should be used as an All Fail record.
7. Select the Probe Threshold value.
8. Select the Record State. The available states include Normal, Force Active, and Force Fail.
9. Choose whether Probes are enabled or disabled for the record.
10. Enter the Priority value. Priority determines the record’s rank compared to other records in the pool.
11. Click Save.

Configure Probes

1. Click the Probe Definitions tab.
2. Click +Add Probe.
3. Select the Probe Type, such as HTTP, DNS, or TCP.
4. Select the Host type. The probe can apply to the pool or to a specific record in the pool.
5. Select the probing regions. A maximum of four regions can be selected.
6. Select the Region Threshold value.
7. Select the Probe Interval value.
8. Complete the probe transaction fields required for the selected probe type.
9. Click Save Probe.

Create Additional Traffic Controller Pools

Repeat the Traffic Controller pool creation steps for each destination that should be used by the Directional pool.

Example:

• dc1.ultraexample.com
• dc2.ultraexample.com

Each Traffic Controller pool should be configured with the records, probes, priorities, weights, and failover behavior needed for that destination.

Create the Directional Pool

After the Traffic Controller pools are created, create the Directional pool and add the Traffic Controller pool hostnames as Directional pool records.

1. From the domain records page, locate the record type that will be used for the Directional pool, such as A or AAAA.
2. Click +Add Pool.
3. In Host, enter the hostname for the Directional pool.
4. In Points To, enter one of the previously created Traffic Controller pool hostnames.
5. In Select Pool Type, select Directional (DIR).
6. Select the Method for the Directional record.
7. Click Save.

Add Directional Pool Records

Add a Directional pool record for each Traffic Controller pool hostname that should be returned for a specific routing rule.

1. Open the Directional pool.
2. Click +Add.
3. Select the applicable Record Type.
4. In Points To, enter the Traffic Controller pool hostname that should answer for the selected Directional group.
5. Select the Method.
6. Select the Group Type and Group Name.
7. Select the applicable Directional Group Type.
8. Complete the required group details for the selected Directional Group Type.
9. Click Save.

Directional Group Types

Directional pools use the selected method and group type to determine which DNS answer is returned.

• Geolocation routes users based on geographic region, such as continent, country, region, state, or province.
• Source IP routes users based on configured IPv4 or IPv6 addresses or ranges.
• ASN routes users based on Autonomous System Number.
• ASN + Geolocation routes users based on a combination of ASN and geographic location.
• Geo Proximity routes users to the resource that is geographically closest to configured latitude and longitude coordinates.

Expected Outcome

The Directional pool returns the Traffic Controller pool hostname that matches the configured Directional rule. The selected Traffic Controller pool then applies its own record selection, probing, failover, backup method, priority, and weight configuration.

Important Notes

• A Traffic Controller pool cannot contain both A and AAAA records. Create separate pools if you need to support both IPv4 and IPv6 destinations.
• For Traffic Controller pools that contain AAAA records, only TCP, HTTP, and DNS probes are supported.
• Directional pools on the zone apex cannot contain CNAME records.
• Combinations of A and CNAME records, or AAAA and CNAME records, are allowed in the same Directional pool.
• The No Response record type can be used to block traffic from specified regions by returning No Error, No Response.
• If both Geolocation and Source IP records exist in the same Directional pool, use Conflict Resolves To to determine which record type takes precedence when both match.
• If EDNS Client Subnet data should not be used for Geolocation routing, enable Ignore ECS. Leave this setting unchanged if you are not familiar with EDNS Client Subnet behavior.