/etc/init.d/ntp prefers DHCP over configured /etc/ntp.conf

Bug #1823098 reported by Haw Loeung on 2019-04-04
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
cloud-images
Undecided
Unassigned
ntp (Ubuntu)
Undecided
Unassigned
Xenial
Undecided
Unassigned

Bug Description

Hi,

On a few instances in a public cloud, mostly seen in GCE, ntp seems incorrectly set up with:

| ubuntu@juju-453c71-0:~$ ntpq -pn
| remote refid st t when poll reach delay offset jitter
| ==============================================================================
| *169.254.169.254 71.79.79.71 2 u 737 1024 377 0.657 0.136 0.147

We have /etc/ntp.conf configured to use ntp.ubuntu.com as a 'pool' host. Turns out, it seems the /etc/init.d/ntp prefers the DHCP version over our configured ntp.conf:

| if [ /var/lib/ntp/ntp.conf.dhcp -nt /etc/ntp.conf ]; then
| NTPD_OPTS="$NTPD_OPTS -c /var/lib/ntp/ntp.conf.dhcp"
| fi

| ubuntu@juju-453c71-0:/etc$ ls -la /var/lib/ntp/ntp.conf.dhcp /etc/ntp.conf
| -rw-r--r-- 1 root root 626 Feb 25 08:54 /etc/ntp.conf
| -rw-r--r-- 1 root root 897 Mar 29 21:00 /var/lib/ntp/ntp.conf.dhcp

I think this is wrong, if /etc/ntp.conf is configured, it should use that over what DHCP/dhclient provides.

| ubuntu@juju-453c71-0:~$ cat /etc/*release
| DISTRIB_RELEASE=16.04
| DISTRIB_DESCRIPTION="Ubuntu 16.04.6 LTS"
| VERSION_ID="16.04"

| ubuntu@juju-453c71-0:~$ dpkg-query -S /etc/init.d/ntp
| ntp: /etc/init.d/ntp

| ubuntu@juju-453c71-0:~$ apt-cache policy ntp
| ntp:
| Installed: 1:4.2.8p4+dfsg-3ubuntu5.9
| Candidate: 1:4.2.8p4+dfsg-3ubuntu5.9
| Version table:
| *** 1:4.2.8p4+dfsg-3ubuntu5.9 500
| 500 http://us-central1.gce.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
| 500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages

Thanks,

Haw

Haw Loeung (hloeung) wrote :

A hacky workaround is the constantly touch/update the timestamp of /etc/ntp.conf.

description: updated
tags: added: xenial
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