live-migration to an invalid host should exist gracefully. Currently, it throws a stack trace

[Kashyap Chamarthy]

Description
-----------
Configure nova, boot a couple of instances, & migrate any instance to a destination (which is invalid -- no compute service on it)

   $ nova live-migration 6fdcafa3-b86b-479e-b1cf-5e6859912e65 test1.foo.bar.com

Actual results:
--------------
An ungraceful stack trace:
#============================#
$ nova live-migration 6fdcafa3-b86b-479e-b1cf-5e6859912e65 test1.foo.bar.com
ERROR: Compute service of maelstrom.lab.eng.pnq.redhat.com is unavailable at this time.
Traceback (most recent call last):

  File "/usr/lib/python2.6/site-packages/nova/openstack/common/rpc/amqp.py", line 276, in _process_data
    rval = self.proxy.dispatch(ctxt, version, method, **args)

  File "/usr/lib/python2.6/site-packages/nova/openstack/common/rpc/dispatcher.py", line 145, in dispatch
    return getattr(proxyobj, method)(ctxt, **kwargs)

  File "/usr/lib/python2.6/site-packages/nova/scheduler/manager.py", line 101, in live_migration
    context, ex, request_spec)

  File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
    self.gen.next()

  File "/usr/lib/python2.6/site-packages/nova/scheduler/manager.py", line 91, in live_migration
    block_migration, disk_over_commit)

  File "/usr/lib/python2.6/site-packages/nova/scheduler/driver.py", line 232, in schedule_live_migration
    self._live_migration_dest_check(context, instance, dest)

  File "/usr/lib/python2.6/site-packages/nova/scheduler/driver.py", line 281, in _live_migration_dest_check
    raise exception.ComputeServiceUnavailable(host=dest)

ComputeServiceUnavailable: Compute service of maelstrom.lab.eng.pnq.redhat.com is unavailable at this time.
 (HTTP 400) (Request-ID: req-248afb33-a9ed-4c68-822a-7dac6bc76cb3)
#============================#

Expected results:
--------------
If the destination host is invalid, live-migration should exist gracefully

[Chuck Short (zulcss)]

I was able to reproduce this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/25347

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/25388

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/25388
Committed: http://github.com/openstack/nova/commit/86031940b313532606449c400bca64707be1797a
Submitter: Jenkins
Branch: master

commit 86031940b313532606449c400bca64707be1797a
Author: Nikola Dipanov <email address hidden>
Date: Tue Mar 26 14:38:09 2013 +0100

    Use format_message on exceptions instead of str()

    This patch changes all usages of unicode() and str() in the API layer
    (and most other reasonable places) into a new format_message method.
    This is done in order to avoid leaking the stack trace back to the
    user through the Remote excepitons.

    This patch deliberately avoids the EC2 api as the way how the EC2 API
    handles responses is being worked on as part of another blueprint.

    Fixes bug 1159755

    Change-Id: I04a74682c4fac9a66ba25b52fd5c7af5e10e81e8

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: milestone-proposed
Review: https://review.openstack.org/25575

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/25575
Committed: http://github.com/openstack/nova/commit/ff4e9a2c325fbe622b40219587d7ac3cc39b51df
Submitter: Jenkins
Branch: milestone-proposed

commit ff4e9a2c325fbe622b40219587d7ac3cc39b51df
Author: Nikola Dipanov <email address hidden>
Date: Tue Mar 26 14:38:09 2013 +0100

    Use format_message on exceptions instead of str()

    This patch changes all usages of unicode() and str() in the API layer
    (and most other reasonable places) into a new format_message method.
    This is done in order to avoid leaking the stack trace back to the
    user through the Remote excepitons.

    This patch deliberately avoids the EC2 api as the way how the EC2 API
    handles responses is being worked on as part of another blueprint.

    Fixes bug 1159755

    Change-Id: I04a74682c4fac9a66ba25b52fd5c7af5e10e81e8

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/folsom
Review: https://review.openstack.org/25641

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/25641
Committed: http://github.com/openstack/nova/commit/056a7df5bfe35f0661565e777019851791f8d2f1
Submitter: Jenkins
Branch: stable/folsom

commit 056a7df5bfe35f0661565e777019851791f8d2f1
Author: Nikola Dipanov <email address hidden>
Date: Tue Mar 26 14:38:09 2013 +0100

    Use format_message on exceptions instead of str()

    This patch changes all usages of unicode() and str() in the API layer
    (and most other reasonable places) into a new format_message method.
    This is done in order to avoid leaking the stack trace back to the
    user through the Remote excepitons.

    This patch deliberately avoids the EC2 api as the way how the EC2 API
    handles responses is being worked on as part of another blueprint.

    Fixes bug 1159755

    (cherry picked from commit 86031940b313532606449c400bca64707be1797a)

    Conflicts:

     nova/api/openstack/compute/contrib/admin_actions.py
     nova/api/openstack/compute/contrib/agents.py
     nova/api/openstack/compute/contrib/console_output.py
     nova/api/openstack/compute/contrib/consoles.py
     nova/api/openstack/compute/contrib/deferred_delete.py
     nova/api/openstack/compute/contrib/fixed_ips.py
     nova/api/openstack/compute/contrib/flavorextraspecs.py
     nova/api/openstack/compute/contrib/flavormanage.py
     nova/api/openstack/compute/contrib/floating_ips_bulk.py
     nova/api/openstack/compute/contrib/hosts.py
     nova/api/openstack/compute/contrib/rescue.py
     nova/api/openstack/compute/contrib/server_password.py
     nova/api/openstack/compute/contrib/server_start_stop.py
     nova/api/openstack/compute/servers.py

    Change-Id: I04a74682c4fac9a66ba25b52fd5c7af5e10e81e8