Chrony not synchronised to NTP in TKGm cluster

Products

• VMware Tanzu Kubernetes Grid Management

Issue/Introduction

TKGm cluster nodes configured to retrieve NTP servers from DHCP option 42. However chrony is not provisioned with NTP Server IPs.

Environment

TKGm cluster with Photon 3

Cause

The VM has both timesyncd and chronyd services configured and it should select chronyd based on the number assigned to the corresponding .list file in /lib/systemd/ntp-units.d/

10-timesyncd.list

50-chronyd.list

But Photon 3 does no honour this and there is a conflict between the 2 services and sometimes it incorrectly selects timesyncd.

Resolution

Upgrade cluster nodes to use Photon 5.

If Photon 3 is required, disable timesyncd service

systemctl disable --now systemd-timesyncd
systemctl restart chronyd

Additional Information

This can be made persistent by creating a custom clusterclass or by applying an overlay to legacy cluster