Bug 1525833
| Summary: | chrony-3.1-2 does not sync with ntp server | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | woosung225 |
| Component: | chrony | Assignee: | Miroslav Lichvar <mlichvar> |
| Status: | CLOSED NOTABUG | QA Contact: | qe-baseos-daemons |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 7.4 | CC: | hasuzuki |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2018-01-02 10:18:03 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
The server is ignored for synchronization of the clock because it's too inaccurate. In the "chronyc sources" output there is "+/- 4695ms", which is larger than the default maxdistance of 3 seconds. The maxdistance option was added in chrony-2.2, so that's why it worked with chrony-2.1. Older versions only have a hardcoded limit for the root dispersion to be smaller than 16 seconds. The tcpdump output shows that the NTP server has a root dispersion of about 3.6 seconds. Is it a Windows NTP server? You can also check the root dispersion with "chronyc ntpdata". A larger maxdistance needs to be set in chrony.conf to allow chronyd to use the server for synchronization. |
Description of problem: Chrony-3.1-2 version has been installed on RHEL 7.4. chrony-3.1-2 does not sync with ntp server. Version-Release number of selected component (if applicable): Chrony-3.1-2 Chrony-3.2 How reproducible: # chronyc sources 210 Number of sources = 1 MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^? 10.xx.xx.x 3 6 377 16 +28ms[ +28ms] +/- 4695ms # chronyc sources -v 210 Number of sources = 1 .-- Source mode '^' = server, '=' = peer, '#' = local clock. / .- Source state '*' = current synced, '+' = combined , '-' = not combined, | / '?' = unreachable, 'x' = time may be in error, '~' = time too variable. || .- xxxx [ yyyy ] +/- zzzz || Reachability register (octal) -. | xxxx = adjusted offset, || Log2(Polling interval) --. | | yyyy = measured offset, || \ | | zzzz = estimated error. || | | \ MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^? 10.xx.xx.xx 3 7 377 36 +30ms[ +30ms] +/- 4791ms # chronyc tracking Reference ID : 00000000 () Stratum : 0 Ref time (UTC) : Thu Jan 01 00:00:00 1970 System time : 0.000000000 seconds fast of NTP time Last offset : +0.000000000 seconds RMS offset : 0.000000000 seconds Frequency : 6.970 ppm fast Residual freq : +0.000 ppm Skew : 0.000 ppm Root delay : 1.000000000 seconds Root dispersion : 1.000000000 seconds Update interval : 0.0 seconds Leap status : Not synchronised # chronyc activity 200 OK 1 sources online 0 sources offline 0 sources doing burst (return to online) 0 sources doing burst (return to offline) 0 sources with unknown address # tcpdump -n -i any port 123 -vvvvv tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes 18:55:19.270779 IP (tos 0x0, ttl 64, id 22960, offset 0, flags [DF], proto UDP (17), length 76) MyIP.54766 > NTP_IP.ntp: [bad udp cksum 0x807a -> 0xfe34!] NTPv4, length 48 Client, Leap indicator: (0), Stratum 0 (unspecified), poll 6 (64s), precision 32 Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec) Reference Timestamp: 0.000000000 Originator Timestamp: 3721974917.258155530 (2017/12/11 18:55:17) Receive Timestamp: 348594726.968448707 (2047/02/24 07:20:22) Transmit Timestamp: 1684403634.382490515 (2089/06/24 01:22:10) Originator - Receive Timestamp: +921587105.710293177 Originator - Transmit Timestamp: -2037571282.875665014 18:55:19.271436 IP (tos 0xc0, ttl 53, id 0, offset 0, flags [DF], proto UDP (17), length 76) NTP_IP.ntp > MyIP.54766: [udp sum ok] NTPv4, length 48 Server, Leap indicator: (0), Stratum 3 (secondary reference), poll 6 (64s), precision -24 Root Delay: 0.193771, Root dispersion: 3.678436, Reference-ID: 150.19.7.82 Reference Timestamp: 3721741712.029829228 (2017/12/09 02:08:32) Originator Timestamp: 1684403634.382490515 (2089/06/24 01:22:10) Receive Timestamp: 3721974919.269163925 (2017/12/11 18:55:19) Transmit Timestamp: 3721974919.269184636 (2017/12/11 18:55:19) Originator - Receive Timestamp: +2037571284.886673409 Originator - Transmit Timestamp: +2037571284.886694120 18:56:23.661063 IP (tos 0x0, ttl 64, id 39816, offset 0, flags [DF], proto UDP (17), length 76) MyIP.32904 > NTP_IP.ntp: [bad udp cksum 0x807a -> 0x9b7b!] NTPv4, length 48 Client, Leap indicator: (0), Stratum 0 (unspecified), poll 6 (64s), precision 32 Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec) Reference Timestamp: 0.000000000 Originator Timestamp: 3721974919.269184636 (2017/12/11 18:55:19) Receive Timestamp: 1641777836.366650475 (2088/02/16 16:52:12) Transmit Timestamp: 2969412072.534118970 (1994/02/05 13:41:12) Originator - Receive Timestamp: -2080197082.902534160 Originator - Transmit Timestamp: -752562846.735065665 18:56:23.661823 IP (tos 0xc0, ttl 53, id 0, offset 0, flags [DF], proto UDP (17), length 76) NTP_IP.ntp > MyIP.32904: [udp sum ok] NTPv4, length 48 Server, Leap indicator: (0), Stratum 3 (secondary reference), poll 6 (64s), precision -24 Root Delay: 0.193771, Root dispersion: 3.679397, Reference-ID: 150.19.7.82 Reference Timestamp: 3721741712.029829228 (2017/12/09 02:08:32) Originator Timestamp: 2969412072.534118970 (1994/02/05 13:41:12) Receive Timestamp: 3721974983.659481047 (2017/12/11 18:56:23) Transmit Timestamp: 3721974983.659527012 (2017/12/11 18:56:23) Originator - Receive Timestamp: +752562911.125362076 Originator - Transmit Timestamp: +752562911.125408041 Steps to Reproduce: 1. 2. 3. Actual results: Time synchronization does not work Expected results: Time synchronization does not work Additional info: I deleted chrony-3.1-2 and confirmed that it synchronize normally when running chrony-2.1.1-3 version. Installing chrony-3.2 is the same thing. What is the avoidance method? [root@MyHost ~]# rpm -qa | grep chrony chrony-3.1-2.el7.centos.x86_64 [root@MyHost ~]# rpm -e chrony [root@MyHost ~]# rpm -ivh chrony-2.1.1-3.el7.centos.x86_64.rpm Preparing... ################################# [100%] Updating / installing... 1:chrony-2.1.1-3.el7.centos ################################# [100%] [root@MyHost ~]# rpm -qa | grep chrony chrony-2.1.1-3.el7.centos.x86_64 [root@MyHost ~]# systemctl start chronyd [root@MyHost ~]# chronyc sources 210 Number of sources = 1 MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* 10.xx.xx.xx 3 6 7 0 -35us[ -18ms] +/- 643ms [root@MyHost ~]#