Qpid max-connections should be set to a multiple of the compute nodes * rpc_conn_pool_size. The default limit is 500, when the limit is hit new virtual machines can not be hit. The default rpc_conn_pool_size value, which determines the size of the connection pool to maintain when connecting to Qpid, is 3.0 (set in Nova?). Tentatively naming Russell Bryant as the SME here.
Russell I think the impetus for this originally came from a comment you made in a mailing list thread, does the description seem accurate to you or is this something that can be (or has been) fixed in packaging?
(In reply to Stephen Gordon from comment #2) > Russell I think the impetus for this originally came from a comment you made > in a mailing list thread, does the description seem accurate to you or is > this something that can be (or has been) fixed in packaging? There's nothing to fix here, really. It's just something you need to tweak on the qpid side for a larger deployment. It's something good to document for OpenStack's usage of Qpid, though. The description in the original comment needs a couple of corrections. First, the default is 30, not 3.0. Second, the value you should set would be the rpc_conn_pool_size * the number of services connecting to qpid. That includes more than just compute nodes. In some deployments, a compute node may be running more than one service. You also have controller nodes to factor in. Further, there are other OpenStack projects besides Nova that use Qpid, so those have to be factored in, as well.
The default for rpc_conn_pool_size is correctly doc'd with 30 in the Config Ref Guide (Common Configuration for Messaging). Looks like the max_connections option is set in qpid's /etc/qpidd.conf, but we don't talk about this at all in the Install Guide aside from ssl. Comment needs to go into intro section in 8.2 - Configuring the Message Broker.
Added new 'Basic Qpid Configuration' (28516 added to 15807) Russell, docs-devel is having issues, but could you please review the new section here? http://file.bne.redhat.com/~slong/docs/Red-Hat-Guides/Installation_and_Configuration_Guide/#Basic_Qpid_Configuration Anything to add? thanks, Summer
(In reply to Summer Long from comment #6) > Added new 'Basic Qpid Configuration' (28516 added to 15807) > > Russell, docs-devel is having issues, but could you please review the new > section here? > > http://file.bne.redhat.com/~slong/docs/Red-Hat-Guides/ > Installation_and_Configuration_Guide/#Basic_Qpid_Configuration > > Anything to add? > thanks, Summer The text is correct. However, I think that having to do the calculation is more complex that needed. I would just say something like: "Qpid configuration is contained in the /etc/qpidd.conf file. For small deployments, its default configuration can be used. However, for most OpenStack deployments, the max-connections value should be increased to a large number, such as 65535."
Topic 28516, rev. 590539 - Updated with review comments. Ready for QA with next package.