Reviewed: https://review.openstack.org/561704 Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=23bd8f62634707fc9896a38ff4dae606c89c6c4b Submitter: Zuul Branch: master
commit 23bd8f62634707fc9896a38ff4dae606c89c6c4b Author: Lee Yarwood <[email protected]> Date: Mon Apr 16 18:08:56 2018 +0100 libvirt: Report the allocated size of preallocated file based disks At present the Libvirt driver can preallocate file based disks using the fallocate command and importantly the `-n` option. This option allocates blocks on the filesystem past the initial EOF of a given file: ``` $ touch test.img ; fallocate -n -l $(( 1024 * 1024 )) test.img $ ll -lah test.img -rw-rw-r--. 1 stack stack 0 Apr 16 13:28 test.img $ du -h test.img 1.0M test.img ``` This results in a miscalculation of the total disk overcommit for file based (excluding ploop) disks as os.path.getsize is currently used to determine the allocated size of these disks: ``` >>> import os >>> os.path.getsize('test.img') 0 ``` Using the above example the disk overcommit would be reported as 1.0M as the disk appears empty yet will report a potential (virtual) size of 1.0M. However as the required blocks have already been allocated on the filesystem the host will report disk_available_least as missing an additional 1.0M, essentially doubling the allocation for each disk. To correct this the allocated size of file based (excluding ploop) disks is reported using `disk_size` from the `qemu-img info` command. This should ensure blocks allocated past the EOF of the file are taken into account and correctly reported as allocated. A future change should ultimately remove the use of the `-n` option with fallocate, however as this would not help disks that have already been allocated this has not been included in this change to simplify backports. Change-Id: If642e51a4e186833349a8e30b04224a3687f5594 Closes-bug: #1764489 ** Changed in: nova Status: In Progress => Fix Released -- 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/1764489 Title: Preallocated disks are deducted twice from disk_available_least when using preallocated_images = space Status in OpenStack Compute (nova): Fix Released Bug description: Description =========== When using preallocated file based disks (preallocate_images = space) with the Libvirt virt driver the reported allocation for each disk appears doubled, leaving disk_available_least under reporting the amount of available resources on a compute node. Originally reported and debugged by mschuppert and mdbooth: https://bugzilla.redhat.com/show_bug.cgi?id=1554265 Steps to reproduce ================== $ crudini --get /etc/nova/nova-cpu.conf DEFAULT preallocate_images space $ nova hypervisor-show eb515aa2-b79e-4f38-a6ea-d493a6e0657f +---------------------------+------------------------------------------+ | Property | Value | +---------------------------+------------------------------------------+ [..] | disk_available_least | 43 | | free_disk_gb | 48 | [..] | local_gb | 48 | | local_gb_used | 0 | [..] +---------------------------+------------------------------------------+ $ nova flavor-show 2 +----------------------------+----------+ | Property | Value | +----------------------------+----------+ [..] | disk | 20 | [..] +----------------------------+----------+ $ nova boot --image cirros-0.3.5-x86_64-disk --flavor 2 test [..] $ nova hypervisor-show eb515aa2-b79e-4f38-a6ea-d493a6e0657f +---------------------------+------------------------------------------+ | Property | Value | +---------------------------+------------------------------------------+ [..] | disk_available_least | 3 | | free_disk_gb | 28 | [..] | local_gb | 48 | | local_gb_used | 20 | [..] +---------------------------+------------------------------------------+ Expected result =============== The allocation for each preallocated disk is reported correctly and removed from disk_available_least. Actual result ============= The allocation for each preallocated disk appears doubled and removed from disk_available_least. Environment =========== 1. Exact version of OpenStack you are running. See the following list for all releases: http://docs.openstack.org/releases/ fb0b785169e5e422b06e82f2eb58e68f6d2008b3 2. Which hypervisor did you use? (For example: Libvirt + KVM, Libvirt + XEN, Hyper-V, PowerKVM, ...) What's the version of that? Libvirt + KVM 2. Which storage type did you use? (For example: Ceph, LVM, GPFS, ...) What's the version of that? file / qcow2 3. Which networking type did you use? (For example: nova-network, Neutron with OpenVSwitch, ...) N/A Logs & Configs ============== See above. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1764489/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
