contour: HTTPProxy multiple timeouts (daily)

What steps did you take and what happened: I have an environment with multiple httpproxy resources defined; they are all running fine, except 2 or 3 times a day where all applications delivered via those are not available anymore (timeout). It usually last for approx. 10 min and then everything comes back to normal.

I checked if I could find any corresponding events, but nothing relevant so far. I’m looking for ideas where to look. I can submit any logs asked if required.

Anything else you would like to add:

• During one of those event, I was able to confirm that the IP used by Envoy is available and answering to the ping. However, a telnet <ip> 80 timed out as well.
• Not a ‘scientific’ method but we observed that this behavior becoming worse over time (it was initially one timeout period in a week and it increased until multiple times a day).

Environment:

• Contour version: 1.4.0
• Kubernetes version: (use kubectl version): 1.16.0
• Kubernetes installer & version: kubespray
• Cloud provider or hardware configuration: vSphere VMs
• OS (e.g. from /etc/os-release): Ubuntu 18.04.3 LTS