resizes an instance is not functioning

[Nagaraju-Bingi]

Unable to resize instance, so added following to make it work.

  following parameters are set in nova.conf:
· allow_resize_to_same_host=True
· scheduler_default_filters=AllHostsFilter
· resize_confirm_window=5

please add them to nova.conf.erb template approproiately

[Nagaraju-Bingi (nagaraju-bingi)]

allow_resize_to_same_host=True

This flag Allow destination machine to match source for resize. Useful when testing in single-host environments. So, with this we are restricting to same compute for the resize instead of migrate VM to appropriate compute based on avaiability of resources. Is this okay to have flag enabled?
· scheduler_default_filters=AllHostsFilter

· resize_confirm_window=5
[NR] Is this okay to auto confirm for the resize??

[Mark T. Voelker (mvoelker)]

I believe the allow_resize_to_same_host parameter merely *allows* the source and destination machine to be the same, but does not force them to be the same (so setting this to true is probably ok, particularly for AIO or small environments).

Changing the scheduler filter list seems like it shouldn't be really necessary here...or am I missing something? Perhaps we could simply expose this for users to adjust as they wish for their particular use cases, but leave the default.

Automatic confirmation of resize does seem a bit dicey. I'd recommend leaving it set to 0 by default but exposing it for users to adjust themselves in user.common.yaml if they so desire.

Was this all that was necessary to make resize work for you? I'm wondering if you wouldn't also need to deal with SSH keys and/or enabling shell access for the nova user.

For the changes mentioned above, I've posted a branch that you can take for a spin here:

https://review.openstack.org/92301

[Ken Schroeder (kschroed)]

From testing that we have done for Nimbus what I had noticed was in fact that. The allow_resize_to_same_host never actually did resize it on the same host. The other requirement that we had to enable to get this working was to setup an ssh trust for nova user as it seems the resize function needed this. Here is code snippet from script were were using at one point that was enabling resize functions outside of setting allow_resize_to_same_host = true.

usermod -s /bin/bash nova
su - nova
mkdir -p -m 700 .ssh && cd .ssh
ssh-keygen -f id_rsa -b 1024 -P ""
scp /var/lib/nova/.ssh/id_rsa.pub root@otherHost:/var/lib/nova/.ssh/authorized_keys
chown nova:nova /var/lib/nova/.ssh/authorized_keys
cat > /etc/ssh/ssh_config <<EOF
   # SSH Config Update for nova resize.
   StrictHostKeyChecking no
   UserKnownHostsFile=/dev/null
EOF

[Mark T. Voelker (mvoelker)]

A recent StackForge commit allowing for SSH key management might be useful here.

https://github.com/stackforge/puppet-nova/commit/eb4a56ca89809508778ce27998204635a2e7b8a2

[Chris Ricker (chris-ricker)]

marking committed as all the resize bits are in / exposed

key management is really a separate issue but may also impact this. See https://bugs.launchpad.net/openstack-cisco/+bug/1322713 for a bug tracking that need