Re: [openstack-dev] design question : green thread model
Hi, nova-conductor starts multiple processes as well. Belmiro On Wednesday, January 28, 2015, Johannes Erdfelt johan...@erdfelt.com wrote: On Wed, Jan 28, 2015, murali reddy muralimmre...@gmail.com javascript:; wrote: On hosts with multi-core processors, it does not seem optimal to run a single service instance with just green thread. I understand that on controller node, we can run one or more nova services but still it does not seem to utilize multi-core processors. Is it not a nova scaling concern? It certainly depends on the service. nova-compute isn't CPU limited for instance, so utilizing multiple cores isn't necessary. nova-scheduler generally isn't CPU limited either in our usage (at Rackspace), but we use cells and as a result, we run multiple independent nova-scheduler services. If you've seen some scaling problems, I know the Nova team is open to reports. In some cases, patches wouldn't be hard to develop to start multiple processes, but no one has ever reported a need beyond nova-api. JE __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
[openstack-dev] design question : green thread model
Hello, I am trying to understand how a nova component can be run parallely on a host. From the developer reference documentation it seems to indicate that all the openstack services use green thread model of threading. Is it the only model of parallelism for all the components or multiple processes can be used for a nova service on a host. Does nova.service which seems to do os.fork is being used to fork multiple processes for a nova service? I am newbie so pardon me if the question is asked before. Thanks Murali __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] design question : green thread model
Thanks JE. On hosts with multi-core processors, it does not seem optimal to run a single service instance with just green thread. I understand that on controller node, we can run one or more nova services but still it does not seem to utilize multi-core processors. Is it not a nova scaling concern? On Wed, Jan 28, 2015 at 10:38 PM, Johannes Erdfelt johan...@erdfelt.com wrote: On Wed, Jan 28, 2015, murali reddy muralimmre...@gmail.com wrote: I am trying to understand how a nova component can be run parallely on a host. From the developer reference documentation it seems to indicate that all the openstack services use green thread model of threading. Is it the only model of parallelism for all the components or multiple processes can be used for a nova service on a host. Does nova.service which seems to do os.fork is being used to fork multiple processes for a nova service? Multiple processes are used in some places, for instance, nova-api can fork multiple processes. Each process would also use greenthreads as well. However, most services don't use multiple processes (at least in Nova). JE __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] design question : green thread model
On Wed, Jan 28, 2015, murali reddy muralimmre...@gmail.com wrote: I am trying to understand how a nova component can be run parallely on a host. From the developer reference documentation it seems to indicate that all the openstack services use green thread model of threading. Is it the only model of parallelism for all the components or multiple processes can be used for a nova service on a host. Does nova.service which seems to do os.fork is being used to fork multiple processes for a nova service? Multiple processes are used in some places, for instance, nova-api can fork multiple processes. Each process would also use greenthreads as well. However, most services don't use multiple processes (at least in Nova). JE __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] design question : green thread model
On Wed, Jan 28, 2015, murali reddy muralimmre...@gmail.com wrote: On hosts with multi-core processors, it does not seem optimal to run a single service instance with just green thread. I understand that on controller node, we can run one or more nova services but still it does not seem to utilize multi-core processors. Is it not a nova scaling concern? It certainly depends on the service. nova-compute isn't CPU limited for instance, so utilizing multiple cores isn't necessary. nova-scheduler generally isn't CPU limited either in our usage (at Rackspace), but we use cells and as a result, we run multiple independent nova-scheduler services. If you've seen some scaling problems, I know the Nova team is open to reports. In some cases, patches wouldn't be hard to develop to start multiple processes, but no one has ever reported a need beyond nova-api. JE __ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
