Linux Networking for Ganeti Clusters, explained

Here is a presentation I made at work regarding how we employ Linux powers to establish the networking base for the Ganeti clusters powering ViMa and ~okeanos cloud installations at GRNET. I plan on writing a detailed blogpost about how IP-less routed networks work and allow us to provide public IPv4 and IPv6 addresses to virtual machines without the burden of sharing the broadcast domain.

Why kernel is dropping frames?

Kernel is dropping packets At work, when we did setup prometheus alerting we started getting nofitications like this: description = ok10-01.okeanos.grnet.gr:9100 is dropping frames at a rate of 0.10340541666666667 frames per sec To output this alert, prometheus-node-exporter reads /proc/net/softnet_stat filepath, which contains a line for every CPU. The 2nd column of each line counts dropped frames in hexadecimal. A nicer output can be provided if we query prometheus directly from within the host:
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Revive this blog, fall 2017

Revive this blog

LEAP GSOC progress report, no5

Progress report, take five