Hello!
I managed to migrate my Xen virtual machines live from one node to another. Soe
of the VMs have several GB of RAM with databases, so live migration takes a
while. However the typical user does not notice that the node migrated (network
connections stay alive). Unfortunately NTP seems to notice the time migration
took (77s in this case):
ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
*127.127.1.0 .LOCL. 10 l 3 64 377 0.000 0.000 0.001
132.199.176.18 192.53.103.108 2 u 180 512 377 0.239 -77753. 41560.8
132.199.176.153 192.53.103.104 2 u 185 512 377 0.275 -77751. 41560.1
172.20.16.1 132.199.176.153 3 u 191 512 377 0.378 -77753. 41560.5
172.20.16.5 132.199.176.18 3 u 251 512 377 0.107 -77754. 41560.2
So it thinks the other nodes are off by 77.7 seconds and sync to ist own clock.
Other VMs show simular results:
# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
*127.127.1.0 .LOCL. 10 l 6 64 377 0.000 0.000 0.001
132.199.176.18 192.53.103.108 2 u 582 1024 377 0.242 -78361. 78359.9
132.199.176.153 192.53.103.104 2 u 546 1024 377 0.521 -78360. 78360.1
# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
*127.127.1.0 .LOCL. 10 l 64 64 377 0.000 0.000 0.001
132.199.176.18 192.53.103.108 2 u 653 1024 377 0.326 -77837. 77836.7
132.199.176.153 192.53.103.104 2 u 969 1024 377 0.453 -77835. 77835.8
172.20.16.1 132.199.176.153 3 u 971 1024 377 4.937 -77837. 77834.5
172.20.16.5 132.199.176.153 3 u 966 1024 377 6.283 -3.295 77836.9
As it turn out, the time in the VMs is actually wrong after migration:
# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
127.127.1.0 .LOCL. 10 l 51 64 377 0.000 0.000 0.001
+132.199.176.18 192.53.103.108 2 u 71 1024 377 0.362 -77840. 2.573
+132.199.176.153 192.53.103.104 2 u 386 1024 377 0.506 -77838. 2.834
*172.20.16.1 132.199.176.153 3 u 391 1024 377 4.140 -77840. 2.744
+172.20.16.5 132.199.176.18 3 u 386 1024 377 3.767 -77841. 1.409
If I want to continue to use NTP, what are the recommendations?
Regards,
Ulrich
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