Question: Is it possible to configure how often AD client will update the krb5.conf? 

Answer: Yes, within the /etc/centrifydc/centrifydc.conf file exists this parameter:

krb5.config.update

This configuration parameter specifies, in hours, how frequently the agent updates the Kerberos configuration file. In most cases, this configuration parameter can be set using group policy. It can, however, be set manually in the configuration file if group policy is not being used or to temporarily override group policy.
If adclient.krb5.autoedit is set to false, this parameter has no effect.
If adclient.krb5.autoedit is set to true, this parameter value must be a positive integer.
For example, to set the update interval to 8 hours: krb5.config.update: 8
If this parameter is not defined in the configuration file, its default value is 8 hours.

You can also find this information in our documentation on page 140