Bug 1272376

Summary:	Duplicate nova hypervisors after rebooting compute nodes
Product:	[Community] RDO	Reporter:	Marius Cornea <mcornea>
Component:	rdo-manager	Assignee:	Hugh Brock <hbrock>
Status:	CLOSED EOL	QA Contact:	Shai Revivo <srevivo>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	Liberty	CC:	chris.brown, jtrowbri, mburns, mfuruta
Target Milestone:	---
Target Release:	Liberty
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:		Doc Type:	Bug Fix
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Clone Of:		Environment:
Last Closed:	2017-07-04 15:03:51 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Marius Cornea 2015-10-16 09:51:29 UTC

Description of problem:
After rebooting a compute node it will come up with the same hypervisor_hostname but a different service_host. During the deployment the compute node will register using the shortname(e.g overcloud-novacompute-0) as service_host and after reboot it will show up with the long name(e.g overcloud-novacompute-0.localdomain) as service_host. 

Version-Release number of selected component (if applicable):
openstack-tripleo-heat-templates-0.8.7-dev284.el7.centos.noarch

How reproducible:
100%

Steps to Reproduce:
1. Deploy overcloud with one controller and one compute
2. Reboot the compute node 
3. Check the overcloud nova hypervisor-list

Actual results:
+----+-------------------------------------+-------+----------+
| ID | Hypervisor hostname                 | State | Status   |
+----+-------------------------------------+-------+----------+
| 1  | overcloud-novacompute-0.localdomain | down  | disabled |
| 2  | overcloud-novacompute-0.localdomain | up    | enabled  |
+----+-------------------------------------+-------+----------+


Expected results:
Only one hypervisor would show up.

Additional info:
stack@instack:~>>> nova hypervisor-show 1 | grep host
| host_ip                   | 192.0.2.19                               |
| hypervisor_hostname       | overcloud-novacompute-0.localdomain      |
| service_host              | overcloud-novacompute-0                  |
stack@instack:~>>> nova hypervisor-show 2 | grep host
| host_ip                   | 192.0.2.19                               |
| hypervisor_hostname       | overcloud-novacompute-0.localdomain      |
| service_host              | overcloud-novacompute-0.localdomain      |

Comment 1 Marius Cornea 2015-10-16 12:10:38 UTC

I believe during provisioning cloud init will set a transient hostname (the short one) and after reboot the static hostname in /etc/hostname will be used:

[heat-admin@overcloud-novacompute-0 ~]$ curl http://169.254.169.254/2007-01-19/meta-data/public-hostname;echo
overcloud-novacompute-0

[heat-admin@overcloud-novacompute-0 ~]$ cat /etc/hostname 
overcloud-novacompute-0.localdomain

Not sure if this realtes to our setup but this behavior was described in this bug:
https://bugs.launchpad.net/cloud-init/+bug/1246485

Comment 4 Christopher Brown 2017-06-17 19:00:51 UTC

Ugh, yeah, this has been going on forever.
The current fix is:

http://blog.nemebean.com/content/prevent-cloud-init-changing-your-hostname-reboot

which is namely:

echo "preserve_hostname: true" > /etc/cloud/cloud.cfg.d/99_hostname.cfg

on firstboot

but I think this can be closed unless we want to make the above fix permanent?