Hi Tim,

Can you please attach both VR’s cloud.log(present in VR path 
/var/log/cloud.log) as well as management server log of the failure case.
Which will help us finding out the exact cause of the failure.


Thanks,
Nitin
On 13-Sep-2017, at 12:42 AM, Tim Gipson 
<tgip...@ena.com.INVALID<mailto:tgip...@ena.com.invalid>> wrote:

Hey all,

I’ve found what I think could be a possible issue with the redundant VPC router 
pairs in Clousdstack.  The issue was first noticed when routers were failing 
over from master to backup.  When the backup router became master, everything 
continued to work properly and traffic flowed as normal.  However, when it 
failed from the new master back to the original master the virtual router 
stopped allowing traffic through any network interfaces and any failover after 
that resulted in virtual routers that were not passing traffic.

I can reproduce this behavior by doing a manual failover (logging in and 
issuing a reboot command on the router) from master to backup and then back to 
the original master.  From what I can tell, the iptables rules on the router 
are somehow modified during the failover (or a manual reboot) in such a way as 
to make them completely nonfunctional.  I did a side-by-side comparison of the 
iptables rules before and after a failover (or a manual reboot) and there are 
definite differences.  Sometimes rules are changed, sometimes they are 
duplicated, and I’ve even found that some rules are missing completely out of 
iptables.

We are running in a CentOS 7 environment and using KVM as our hypervisor.  Our 
CS version is 4.8 with standard images for the VRs.  As mentioned previously, 
our VRs are in redundant pairs for VPCs.

I’ve attached two iptables outputs, one from a working router and one from a 
broken router after failover.

Any help or direction you could provide to help me further identify why this is 
happening would be appreciated.

Thanks!

Tim Gipson
<https://www.ena.com/>



<iptables_broken.txt><iptables_working.txt>

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