adding reserved_huge_pages option

[Sahid Orentino]

In situation where huge pages is enabled on host, if a third party component is also using some of them Nova wont be notified and can believe that the host provides enough huge pages to map guests on.

The boot process can fail with such error raised by QEMU:

  os_mem_prealloc: Insufficient free host memory pages available to allocate guest RAM

To avoid this Nova is providing an option DEFAULT/reserved_huge_pages, that one should be configured per host NUMA nodes:

  [DEFAULT]
  reserved_huge_pages=node:0,size:1GB,count:4
  reserved_huge_pages=node:1,size:1GB,count:4

Since juju does not support yet list of options that one will be exposed using semicolon in charm.

  reserved_huge_pages=node:0,size:1GB,count:4;node:1,size:1GB,count:4

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/616630
Committed: https://git.openstack.org/cgit/openstack/charm-nova-compute/commit/?id=c7638a340ad77bc70591836d02429ced309b7129
Submitter: Zuul
Branch: master

commit c7638a340ad77bc70591836d02429ced309b7129
Author: Sahid Orentino Ferdjaoui <email address hidden>
Date: Thu Nov 8 17:52:01 2018 +0100

    introduce "reserved_huge_pages" option

    The DEFAULT/reserved_huge_pages option will be required by NFV
    deployments in order to let Nova compute service knows that some huge
    pages allocated in the host are used by third-party components like
    DPDK PMDs.

    Since juju does not support yet list of strings options that one will
    be exposed using semicolons in charm.

    Closes-Bug: 1804169
    Change-Id: I7faa3406a6bd27b9d924925ae93d40075eb0aff2
    Signed-off-by: Sahid Orentino Ferdjaoui <email address hidden>

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/640109

[Edward Hope-Morley (hopem)]

Adding config to rocky nova.conf - https://review.openstack.org/640109

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/640109
Committed: https://git.openstack.org/cgit/openstack/charm-nova-compute/commit/?id=a37c470e1fe1a51c4e0935ffe10ac1bd7f8810b7
Submitter: Zuul
Branch: master

commit a37c470e1fe1a51c4e0935ffe10ac1bd7f8810b7
Author: Edward Hope-Morley <email address hidden>
Date: Thu Feb 28 17:04:47 2019 +0000

    Add config missing in rocky template

    These nova.conf config were added while rocky was being added and
    so didnt make it into the rocky nova.conf (since the template didnt
    exist when the patches were started).

    Change-Id: Ie4d3ba515cb0a6f9f7fa198a9ac1c05c4c2c233a
    Related-Bug: #1804169
    Related-Bug: #1799916