Reproduced again on BVT:

node-1 2015-08-20T23:51:20.014281 err: Could not prefetch keystone_endpoint provider 'openstack': Execution of '/usr/bin/openstack endpoint list --quiet --format csv --long' returned 1: ERROR: openstack Service Unavailable (HTTP 503)
node-1 2015-08-20T23:51:20.014609 err:
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util/execution.rb:188:in `execute'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/provider/command.rb:23:in `execute'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/provider.rb:237:in `block in has_command'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/openstacklib/lib/puppet/provider/openstack.rb:26:in `block (2 levels) in request'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/openstacklib/lib/puppet/provider/openstack.rb:23:in `loop'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/openstacklib/lib/puppet/provider/openstack.rb:23:in `block in request'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util.rb:43:in `withenv'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/openstacklib/lib/puppet/provider/openstack.rb:19:in `request'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/openstacklib/lib/puppet/provider/openstack/auth.rb:44:in `request'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/keystone/lib/puppet/provider/keystone.rb:110:in `request'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/keystone/lib/puppet/provider/keystone_endpoint/openstack.rb:82:in `instances'
node-1 2015-08-20T23:51:20.015448 err: /etc/puppet/modules/keystone/lib/puppet/provider/keystone_endpoint/openstack.rb:97:in `prefetch'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/transaction.rb:277:in `prefetch'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/transaction.rb:167:in `prefetch_if_necessary'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/transaction.rb:67:in `block in evaluate'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/graph/relationship_graph.rb:116:in `call'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/graph/relationship_graph.rb:116:in `traverse'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/transaction.rb:108:in `evaluate'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/resource/catalog.rb:164:in `block in apply'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util/log.rb:149:in `with_destination'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/transaction/report.rb:108:in `as_logging_destination'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/resource/catalog.rb:163:in `apply'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/configurer.rb:125:in `block in apply_catalog'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util.rb:161:in `block in benchmark'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/1.9.1/benchmark.rb:295:in `realtime'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util.rb:160:in `benchmark'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/configurer.rb:124:in `apply_catalog'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/configurer.rb:192:in `run'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application/apply.rb:268:in `apply_catalog'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application/apply.rb:218:in `main'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application/apply.rb:146:in `run_command'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application.rb:364:in `block (2 levels) in run'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application.rb:470:in `plugin_hook'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/application.rb:364:in `block in run'
node-1 2015-08-20T23:51:20.015448 err: /usr/lib/ruby/vendor_ruby/puppet/util.rb:478:in `exit_on_fail'
node-1 2015-08-20T23:51:20.016451 err: /usr/lib/ruby/vendor_ruby/puppet/application.rb:364:in `run'
node-1 2015-08-20T23:51:20.016451 err: /usr/lib/ruby/vendor_ruby/puppet/util/command_line.rb:137:in `run'
node-1 2015-08-20T23:51:20.016451 err: /usr/lib/ruby/vendor_ruby/puppet/util/command_line.rb:91:in `execute'
node-1 2015-08-20T23:51:20.016451 err: /usr/bin/puppet:4:in `<main>'