Configuring GTM with cloud-based services

You might need to use GTM to balance load between two or more servers in the cloud. The provider provides a hostname for each cloud region that resolves to one or more virtual machines in a the region.

Before you begin

GTM was designed to load balance between data centers with static IP addresses, not between VM environments or cloud-based services that need to be load balanced between changing IP addresses.

By default, monitoring agents probe each data center based on the frequency of the liveness test configured. The monitoring agents perform a DNS lookup on data center hostnames every 15 minutes, regardless of the DNS TTL associated with it. This might be a problem if the IP address of the Akamai liveness test has been taken down or replaced with another virtual machine within the 15 minutes default DNS lookup frequency of the monitoring agents.

To have GTM liveness test agents perform a host resolution at the time of the test, you need to enable Cloud Server Targeting in the data center.

You cannot enable Cloud Server Targeting with the geographic map, CIDR, or IP version selector property types.

This procedure enables the Cloud Server Target feature on a data center.

How to

  1. On the Traffic Management Domains, select the domain you want to use to balance the load between cloud-based servers. The Edit Domain Settings page appears.
  2. Click the Data Centers tab and select a data center from the Data Center Name column. In this example, click APHW 1. The Data Center Information field appears.
  3. Click the Cloud Server Targeting checkbox and then click Add to Change List. An orange circle icon appears in the Modified column, indicating that the data center is modified.
    If you receive messages stating the following you must fix the issues before you can save the changes:
    • The traffic target Servers field should have only one hostname.
    • The traffic target Servers field should not contain an IP address.
    • The traffic target Servers and handout CNAME field are both not empty and should match.
    Note: If you turn off existing Cloud Server Targeting for a data center that had it turned on, you should see the server hostname in both the server name field and the handout CNAME field in all traffic targets for that data center.
  4. Click on Review Change List. The Change List Detail dialog appears.
  5. Review the Change List Detail dialog changes, validate them, add a required comment, and click Activate Domain to save the changes. A green banner appears at the top of the page indicating that enabling Cloud Server Targeting was successful.
    See Change List Detail Dialog for more information.

What you should see

If Cloud Server Targeting is enabled for a data center, there is only one field name for a single target hostname, which is stored in the database as both the server name and handout CNAME. This eliminates the need to have separate text fields in which to enter target hostnames and handout CNAMEs.

The Cloud Server Target is also inherited by data center clones.