Heat templates with cinder volumes

While trying to launch several VMs using heat templates on RHEL OpenStack Liberty only 2 out of 8 launched. Rest failed because cinder volumes could not be created.

heat stack status was CREATE_FAILED and cinder volume status was error

/var/log/cinder/volume.log

HTTPInternalServerError: HTTPInternalServerError (HTTP 500)
(...)
Unable to get internal tenant context: Missing required config parameters.
(...)
Unable to get Cinder internal context, will not use image-volume cache

For a brief moment there was some log on a console related to haproxy failure

While checking the services I noticed that both haproxy and swift-proxy are not running so just decided to restart them:

systemctl restart haproxy.service
systemctl start openstack-swift-proxy.service

After that I could again create cinder volumes via heat templates. So be careful – create VMs from templates with cinder one by one.