Is there a way to dynamically enable debugging for nova-compute?

asked 2015-02-13 12:21:37 -0600

dale-aavang gravatar image

I have an icehouse installation running on red hat 6.5 and is using qpidd for messaging. I am debugging a problem where it appears the nova-compute process on a couple of our blades has stopped processing requests to create new VM instances.

When I launch a VM and specify to place it on this specific compute host, the VM gets stuck in the "building" state.

I have seen this a few times in the past, and am pretty confident that if I restart the nova-compute service on this compute blade, the problem will be resolved.

For this reason, I am trying to find out the state of the nova-compute process, without killing it. Unfortunately, I currently do not have debug enabled via the nova.conf file, so am looking to see if the debug setting can be enabled without restarting the process?

for completeness, the "nova service-list" command shows the nova-compute service on this compute blade to be in-service...

Looking at qpid-stat -q, I see that a new message was sent and received by the compute blade (no unread messages in the queue)...but the VM is never created on the compute, there are no newly created messages in /var/log/nova/compute.log and no new entries in /var/log/libvirt/* when I attempt to create a new VM.

I have tried restarting libvirtd on the compute and that didn't help. I have also restarted the qpidd service and while that did trigger the nova-compute process to log some message regarding the loss (and reconnection) of the connection to the AMPQ server, it still didn't have an impact on being able to get nova-compute to start a new VM.

Any suggestions on how to figure out what the state of nova-compute is internally? Anyone else encounter this recently on icehouse? I have seen this problem described in tickets from 2012...but haven't seen much from more recent times.

The installed nova-compute RPM versions are: [root@compute-0-0 nova]# rpm -qa | grep nova-co openstack-nova-common-2014.1.1-3.el6ost.noarch openstack-nova-compute-2014.1.1-3.el6ost.noarch

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answered 2018-04-18 02:59:00 -0600

ghanshyammann gravatar image

Now you can do that. This means you change debug config option value and reload them (usually via SIGHUP) at runtime, without a service restart.

Nova has done that support since newton i think. You can get more info here -

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Asked: 2015-02-13 12:21:37 -0600

Seen: 804 times

Last updated: Apr 18 '18