Public bug reported: Description ===========
Using the libvirt driver and a host OS that uses cgroups v2 (RHEL 9, Ubuntu Jammy), an instance with more than 16 CPUs cannot be booted. Steps to reproduce ================== 1. Boot an instance with 10 (or more) CPUs on RHEL 9 or Ubuntu Jammy using Nova with the libvirt driver. Expected result =============== Instance boots. Actual result ============= Instance fails to boot with a 'Value specified in CPUWeight is out of range' error. Environment =========== Originially report as a libvirt but in RHEL 9 [1] Additional information ====================== This is happening because Nova defaults to 1024 * (# of CPUs) for the value of domain/cputune/shares in the libvirt XML. This is then passed directly by libvirt to the cgroups API, but cgroups v2 has a maximum value of 10000. 10000 / 1024 ~= 9.76 [1] https://bugzilla.redhat.com/show_bug.cgi?id=2035518 ** Affects: nova Importance: Undecided Status: In Progress -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1978489 Title: libvirt / cgroups v2: cannot boot instance with more than 16 CPUs Status in OpenStack Compute (nova): In Progress Bug description: Description =========== Using the libvirt driver and a host OS that uses cgroups v2 (RHEL 9, Ubuntu Jammy), an instance with more than 16 CPUs cannot be booted. Steps to reproduce ================== 1. Boot an instance with 10 (or more) CPUs on RHEL 9 or Ubuntu Jammy using Nova with the libvirt driver. Expected result =============== Instance boots. Actual result ============= Instance fails to boot with a 'Value specified in CPUWeight is out of range' error. Environment =========== Originially report as a libvirt but in RHEL 9 [1] Additional information ====================== This is happening because Nova defaults to 1024 * (# of CPUs) for the value of domain/cputune/shares in the libvirt XML. This is then passed directly by libvirt to the cgroups API, but cgroups v2 has a maximum value of 10000. 10000 / 1024 ~= 9.76 [1] https://bugzilla.redhat.com/show_bug.cgi?id=2035518 To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1978489/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp