nova-compute hugepages breaks the boot process

[PshemK]

Once hugepages are enabled in the charm:

nova-compute:
 openstack-origin: cloud:trusty-liberty
 enable-live-migration: true
 migration-auth-type: ssh
 enable-resize: true
 hugepages: "16834"

The reload of the physical host stops at:

An error occurred while mounting /run/hugepages/kvm
keys: Press S to skip mounting or M for manual recovery

pressing S progresses the boot process

Having a look at the log files I can see the following in /var/log/upstart/mountall.log:

mount: mount point /run/hugepages/kvm does not exist
mountall: mount /run/hugepages/kvm [704] terminated with status 32
mountall: Filesystem could not be mounted: /run/hugepages/kvm
Skipping /run/hugepages/kvm at user request

hugepages end up being mounted anyway:

# cat /proc/mounts | grep hugepages
nodev /run/hugepages/kvm hugetlbfs rw,relatime,mode=1770,gid=0,pagesize=2MB 0 0

[James Page (james-page)]

Thanks for the bug report Pshem

This problem occurs because /run is entirely fungible on a reboot; mounting the hugepage filesystem here is not going to work via an fstab entry for this reason; I suspect that the charm just deals with this post-reboot when the config-changed hook fires.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/304097

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/304097
Committed: https://git.openstack.org/cgit/openstack/charm-nova-compute/commit/?id=0279111eeb03d506b93bba6fdb51f4e43a0a473c
Submitter: Jenkins
Branch: master

commit 0279111eeb03d506b93bba6fdb51f4e43a0a473c
Author: Liam Young <email address hidden>
Date: Mon Apr 11 12:31:31 2016 +0000

    Remove hugepage fstab entry and use qemu-kvm init

    The hugepages fstab entry can stop systems from booting if the
    /run filesystem is not available. The qemu-kvm init script can
    be used to enable hugepages by setting KVM_HUGEPAGES=1

    This apporach works for both upstart and systemd (where the old
    System V script is used). However, for a systemd system the
    prefered approach would be to enable hugepages via kernel
    parameters set in MAAS.

    Change-Id: Ib91ca930a91da3d75dbd96f7d55e7e259cb50fd1
    Closes-Bug: 1518771