Transient Connection Issue

[Tomcsanyi, Domonkos]

Hi Ashish,

With the amount of information given it is very hard to comment anything meaningful.
Have you gone through standard network connectivity issue investigation steps?
E.g.: does ping work? Do you have correct routes setup? What does wg show tell during downtime? What does tcpdump shows on the wire?

Cheers,
Domi


> 10.11.2020 dátummal, 0:21 időpontban Ashish Madeti <ashish at provakil.com> írta:
> 
> Hi All
> 
> Background: I am using Wireguard VPN to secure intra-server
> communications among my 5-6 ubuntu servers sitting in different data
> centers.
> 
> Today, we had a downtime of around 15 minutes because the server
> running nginx was not able to connect to the web-application server
> using the wireguard interface [0]. I ascertained that it was not a
> connection issue between nginx server and web-application server by
> trying to connect to web-application server via its public IP, which
> worked [1]. I even tried restarting wireguard service [2] on both
> nginx and web-application server but to no avail.
> So, before investigating further, I decided to first route all the
> traffic to a failover server (which was also a part of the VPN). It
> took me around 5-10 minutes to pull the latest configuration and
> application changes onto the failover server and then route all
> traffic to it. Once our site was up, I again tried connecting to the
> original web-application server from nginx server, using curl, but
> this time it worked fine.
> 
> Can anybody help me understand the problem or anything I should try if
> it happens again?
> 
> Please let me know if you need any more information.
> 
> [0] Tried via curl. curl 10.0.0.10:8080. Received the error
> 'Connection timed out'
> [1] curl w.x.y.z:8080 returned the html content as expected.
> [2] sudo service wg-quick at wg0 restart
> 
> Regards
> -- 
> Ashish Madeti