I have come across this issue a while ago on our Openstack testbed that as the amount of API calls increase, the delay when you do API calls increased. Then I discovered that Openstack does not clean the expired tokens automatically when you are using a SQL backend.
https://bugs.launchpad.net/ubuntu/+source/keystone/+bug/1032633
To delete the expired tokens I have created a script so that I can automate this, by creating a cron job.
You can find the script here on my github. Download the script and change the password to your mysql password.
Then create a cron job to periodically execute this script.
However this problem is solved in Openstack Havana release.
https://blueprints.launchpad.net/keystone/+spec/keystone-manage-token-flush
https://bugs.launchpad.net/ubuntu/+source/keystone/+bug/1032633
To delete the expired tokens I have created a script so that I can automate this, by creating a cron job.
You can find the script here on my github. Download the script and change the password to your mysql password.
Then create a cron job to periodically execute this script.
0 0 * * * /path/to/keystone_flush 2>&1 >> /path/to/log/keystone_flush.log
Above cron job will run ones everyday. You may change the timing of the job as you desire.
However this problem is solved in Openstack Havana release.
https://blueprints.launchpad.net/keystone/+spec/keystone-manage-token-flush
