VM timekeeping: Using the PTP Hardware Clock on KVM

Contents Background Performance improvements - chrony Common prerequisite Chronyd configuration Ntpd configuration Performance improvements - ntpd Next steps Thanks Background In my last post I described the setup I use to provide time...

The Little Network That Could: Time Infrastructure

Contents Background NTP root servers Bare metal VM hosts NTP pool VMs Monitoring Future plans Background In my recent posts I've been focusing on time synchronisation in virtual machines in public clouds. In my upcoming posts I'm going to cover...

AWS microsecond accurate time: a first look

Contents The AWS time sync service Microsecond-accurate time announced How it works Prerequisites Chrony configuration Measurements Conclusion Afterthought (Note: Readers who aren't familiar with time sync in public clouds might want to check out...

An update on NTPmon

Over the past few weeks I've made some changes to my NTP health monitor NTPmon, and I want to explain them more fully and outline the roadmap from here. 2.0.x series It was pointed out to me that it wasn't actually clear how to run NTPmon for...

A Tale of Two /tmp Bugs

Part 1: Even maildirs need their personal space I did a migration of my mail server over the last weekend and I ran into a strange error when I brought things back online. My system was receiving mail fine, but it was being deferred in the...

Network troubleshooting fun

This morning I walked out of the bedroom to make my morning coffee and was greeted with a tech support problem. My wife had been up for a while already, and said something was wrong with the network. Coffee in hand, I opened the laptop and was...

Tech nibble: Linux bridge VLAN filtering

[For more context: see Tech nibble: KVM host networking topologies] Traditional VLAN bridging and its problems Linux bridges have been the traditional means of connecting KVM guests, and VLAN support is usually the means by which they are...