Validate live migration procedure and update doc accordingly

[Razique Mahroua]

For Diablo procedure here :
http://docs.openstack.org/diablo/openstack-compute/admin/content/configuring-live-migrations.html
According to Charles Russell the procedure doesn't work for Diablo.
Doc update required

[Tom Fifield (fifieldt)]

This bug is still valid for Essex.

The documentation should be tested in Essex / Precise 12.04.

[Tom Fifield (fifieldt)]

No progress in months - marking as confirmed.

[Tom Fifield (fifieldt)]

Here's Charles Russell's comment, with remarks from my testing:

> These instruction are designed to nova-compute running as root, but in the current implementation they run as nova.

Confirmed - this is the main thing needed to fix this document.

> And nfs will not work correctly if the uid and gid do not align between compute servers.

Confirmed.

>For the alignment to occur with the least ammount of rework I performed the following:
>
>ON BOTH COMPUTE Systems:
>
>Edit /etc/default/nfs-common
>
>NEED_IDMAPD=yes
>Then adjust the idmapd.conf mappings, change user to nova.

NB: IDMAPD is only for NFS4, but this is what our guide is using, so ... good!

> This assumes, when viewing /etc/passwd that your gid is 65534 which = nobody.

Confirmed.

We should fix all of the NFS stuff to make it consistent with: https://help.ubuntu.com/community/SettingUpNFSHowTo

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/7602

[Tom Fifield (fifieldt)]

Attempted fix at https://review.openstack.org/7602 - feedback desired!

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/7602
Committed: http://github.com/openstack/openstack-manuals/commit/238334f5863f6f41516295cc561faec980eec152
Submitter: Jenkins
Branch: master

commit 238334f5863f6f41516295cc561faec980eec152
Author: Tom Fifield <email address hidden>
Date: Sun May 20 12:56:54 2012 +1000

    Updates live migration doc to work with nova user

    Fixes bug 887358
    Update to Live Migration section of the compute manual to address
    issues with the NFS configuration that would cause it to fail if
    used with Diablo or Essex.

    Where possible I have tried to refer readers to the excellent Ubuntu
    documentation in preference for copy & pasting sections on generic
    systems administration tasks (i.e. configuring NFS).

    I have only tested this doc on a similar, but not identical setup,
    so there could well be issues remaining. However, I feel that this is
    an improvement enough (it has a chance of working!) to check it in.
    Your feedback most welcome.

    Fixes bug 891082
    By linking to the existing GlusterFS document that can be used in
    place of NFS

    Change-Id: If076bf9103d71e584bdffc026741947f133fa381

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/essex
Review: https://review.openstack.org/9096

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/9096
Committed: http://github.com/openstack/openstack-manuals/commit/58dfdbf4f307da8e6afb0cf7ca77feacc07163e0
Submitter: Jenkins
Branch: stable/essex

commit 58dfdbf4f307da8e6afb0cf7ca77feacc07163e0
Author: Tom Fifield <email address hidden>
Date: Sun May 20 12:56:54 2012 +1000

    Updates live migration doc to work with nova user

    Fixes bug 887358
    Update to Live Migration section of the compute manual to address
    issues with the NFS configuration that would cause it to fail if
    used with Diablo or Essex.

    Where possible I have tried to refer readers to the excellent Ubuntu
    documentation in preference for copy & pasting sections on generic
    systems administration tasks (i.e. configuring NFS).

    I have only tested this doc on a similar, but not identical setup,
    so there could well be issues remaining. However, I feel that this is
    an improvement enough (it has a chance of working!) to check it in.
    Your feedback most welcome.

    Fixes bug 891082
    By linking to the existing GlusterFS document that can be used in
    place of NFS

    Cherry-picked from https://review.openstack.org/#/c/7602/

    Change-Id: If076bf9103d71e584bdffc026741947f133fa381