11 minutes mode in RHEL 8 and RHEL 9
Issue
- In RHEL8/9,
timedatectl
can not be used to check 11 minutes mode is on and working or not. - Command
timedatectl
reports "System clock synchronized: yes" even if "rtcsync" is commented in /etc/chrony.conf.
[root@vm80 etc]# grep rtc /etc/chrony.conf
#rtcsync
[root@vm80 etc]# timedatectl
Local time: Tue 2020-01-21 15:45:55 JST
Universal time: Tue 2020-01-21 06:45:55 UTC
RTC time: Tue 2020-01-21 06:45:54
Time zone: Asia/Tokyo (JST, +0900)
System clock synchronized: yes <===
NTP service: active
RTC in local TZ: no
- Unreliable RTC synchronization (11-minute mode) in RHEL 8 (prior to kernel-4.18.0-348.el8), it may take a very long time to actually set the RTC. RHEL 9 doesn't have this issue.
- RTC synchronization (11-minute mode) doesn't work on KVM
Environment
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
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