DNS-Derived Autoscaling
This feature is also available as a Service Discovery plug-in, with additional customization options. For more information, see Service Discovery.
The Virtual Traffic Manager can use DNS records to automatically expand or shrink the number of nodes in a pool to meet the demands of the traffic it is handling. This mechanism is known as DNS-derived autoscaling.
If a DNS record for a hostname resolves to multiple IP addresses, and the number of addresses changes depending on the resources available, that change can be reflected in the nodes used in a pool. For example, backend.example.com might resolve initially to four IPv4 records, and then later resolve to six IPv4 records. The Virtual Traffic Manager updates the node list in the pool to include the new IP addresses.
The Virtual Traffic Manager performs updates at 30 second intervals.
To configure a pool to use DNS-derived autoscaling, click Pools > Edit > DNS-derived autoscaling. The following settings apply:
Setting | Description |
|---|---|
dns_autoscale!enabled | To enable DNS-derived autoscaling for a pool, set this key to Yes. By default, pools are not auto-scaled. |
dns_autoscale!hostnames | A list of DNS hostnames that the Virtual Traffic Manager periodically queries. Any IPv4 A or IPv6 AAAA records are added or removed to this pool's list of nodes. |
dns_autoscale!port | The port number the Virtual Traffic Manager appends to every node added using DNS-derived autoscaling. |