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Description of problem:
When the DHCP lease is renewed and there's a change in the NTP server, the
dispatcher scripts are not run and therefore chrony is not updated
to use the new NTP server.
The only workaround is to bring down/up the connection via nmcli. After
the connection is brought back up, chrony shows the updated NTP server.
Version-Release number of selected component (if applicable):
This has been tested on NetworkManager-1.36.0-7.el8_6 and
NetworkManager-1.40.0-5.el8_7, both behave as described above.
When testing the same on NetworkManager-1.32.10-5.el8_5, a "dhcp4-change"
event is triggered when the NTP-server option changes, the dispatcher
scripts are run, and chrony is updated successfuly with the new NTP server.
Looks like a problem introduced in RHEL8.6 after NM was updated from 1.32 to 1.36
How reproducible:
Always
Steps to Reproduce:
* create a pair of veth, add a new ns for the peer, configure an IP on the
peer, and build a DHCP NM connection on the client
$ sudo ip link add dhcpifc type veth peer name dhcpifd
$ sudo ip netns add dhcps
$ sudo ip link set dhcpifd netns dhcps
$ sudo nmcli con add con-name dhcpifc type ethernet \
ifname dhcpifc ipv6.method disabled ipv4.method auto \
ipv4.ignore-auto-routes yes
$ sudo ip netns exec dhcps ip add add 10.9.9.1/24 dev dhcpifd
$ sudo ip netns exec dhcps ip link set dhcpifd up
* Run a simple dnsmasq dhcp server with a short lease time on the peer interface:
$ sudo ip netns exec dhcps dnsmasq -d -C- <<EOF
interface=dhcpifd
port=0
dhcp-range=10.9.9.100,10.9.9.110,255.255.255.0,60s
dhcp-option=option:ntp-server,10.9.9.12
EOF
* Bring the DHCP connection up. Wait until the DHCP settings are configured
$ sudo nmcli con dhcpifc up
* Check the chrony sources. The NTP server provided initially is configured
$ sudo chronyc -n sources | grep 10.9
^? 10.9.9.12 0 7 0 - +0ns[ +0ns] +/- 0ns
* Before the DHCP is renewed, modify the NTP server option and re-run dnsmasq
$ sudo ip netns exec dhcps dnsmasq -d -C- <<EOF
interface=dhcpifd
port=0
dhcp-range=10.9.9.100,10.9.9.110,255.255.255.0,60s
dhcp-option=option:ntp-server,10.9.9.10
EOF
* After the renewal, re-check the chrony sources. The new NTP server has not been configured
$ sudo chronyc -n sources | grep 10.9
^? 10.9.9.12 0 8 0 - +0ns[ +0ns] +/- 0ns
Actual results:
Chrony is not updated to use new NTP server provided
Expected results:
Chrony should be updated to use new NTP server provided
Additional info:
This is easily reproducible on RHEL8.6+ and RHEL9 using the mentioned NetworkManager versions.
If there's log/trace required please let me know and I'll upload it.
This affects me as well by not running scripts in `/etc/NetworkManager/dispatcher.d/` on every `dhcp4-change` event. My use case is removing classless static routes issued by DHCPv4 since NetworkManager doesn't seem to have a setting for retaining the default route but ignoring classless static routes.
I've put the following script in that directory on both RHEL 9 and Fedora 38:
```bash
#!/usr/bin/sh
export LC_ALL=C
interface=$1
action=$2
echo "[ $(date '+%F %T.%N') ] NM-dispatch: ($interface) $action" >> /tmp/nm-dispatch.log
exit 0
```
Every `dhcp4-change` event logged in `journalctl --unit=NetworkManager.service` has a corresponding entry in `/tmp/nm-dispatch.log` on Fedora 38 whereas it only appears on RHEL 9 when interfaces go up and down.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (NetworkManager bug fix and enhancement update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2023:6585
Description of problem: When the DHCP lease is renewed and there's a change in the NTP server, the dispatcher scripts are not run and therefore chrony is not updated to use the new NTP server. The only workaround is to bring down/up the connection via nmcli. After the connection is brought back up, chrony shows the updated NTP server. Version-Release number of selected component (if applicable): This has been tested on NetworkManager-1.36.0-7.el8_6 and NetworkManager-1.40.0-5.el8_7, both behave as described above. When testing the same on NetworkManager-1.32.10-5.el8_5, a "dhcp4-change" event is triggered when the NTP-server option changes, the dispatcher scripts are run, and chrony is updated successfuly with the new NTP server. Looks like a problem introduced in RHEL8.6 after NM was updated from 1.32 to 1.36 How reproducible: Always Steps to Reproduce: * create a pair of veth, add a new ns for the peer, configure an IP on the peer, and build a DHCP NM connection on the client $ sudo ip link add dhcpifc type veth peer name dhcpifd $ sudo ip netns add dhcps $ sudo ip link set dhcpifd netns dhcps $ sudo nmcli con add con-name dhcpifc type ethernet \ ifname dhcpifc ipv6.method disabled ipv4.method auto \ ipv4.ignore-auto-routes yes $ sudo ip netns exec dhcps ip add add 10.9.9.1/24 dev dhcpifd $ sudo ip netns exec dhcps ip link set dhcpifd up * Run a simple dnsmasq dhcp server with a short lease time on the peer interface: $ sudo ip netns exec dhcps dnsmasq -d -C- <<EOF interface=dhcpifd port=0 dhcp-range=10.9.9.100,10.9.9.110,255.255.255.0,60s dhcp-option=option:ntp-server,10.9.9.12 EOF * Bring the DHCP connection up. Wait until the DHCP settings are configured $ sudo nmcli con dhcpifc up * Check the chrony sources. The NTP server provided initially is configured $ sudo chronyc -n sources | grep 10.9 ^? 10.9.9.12 0 7 0 - +0ns[ +0ns] +/- 0ns * Before the DHCP is renewed, modify the NTP server option and re-run dnsmasq $ sudo ip netns exec dhcps dnsmasq -d -C- <<EOF interface=dhcpifd port=0 dhcp-range=10.9.9.100,10.9.9.110,255.255.255.0,60s dhcp-option=option:ntp-server,10.9.9.10 EOF * After the renewal, re-check the chrony sources. The new NTP server has not been configured $ sudo chronyc -n sources | grep 10.9 ^? 10.9.9.12 0 8 0 - +0ns[ +0ns] +/- 0ns Actual results: Chrony is not updated to use new NTP server provided Expected results: Chrony should be updated to use new NTP server provided Additional info: This is easily reproducible on RHEL8.6+ and RHEL9 using the mentioned NetworkManager versions. If there's log/trace required please let me know and I'll upload it.