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Commit | Line | Data |
---|---|---|
1 | Time Synchronization | |
2 | -------------------- | |
3 | ifdef::wiki[] | |
4 | :pve-toplevel: | |
5 | endif::wiki[] | |
6 | ||
7 | The {pve} cluster stack itself relies heavily on the fact that all | |
8 | the nodes have precisely synchronized time. Some other components, | |
9 | like Ceph, also won't work properly if the local time on all nodes is | |
10 | not in sync. | |
11 | ||
12 | Time synchronization between nodes can be achieved using the ``Network | |
13 | Time Protocol'' (`NTP`). As of {pve} 7, `chrony` is used as the default | |
14 | NTP daemon, while {pve} 6 uses `systemd-timesyncd`. Both come preconfigured to | |
15 | use a set of public servers. | |
16 | ||
17 | IMPORTANT: If you upgrade your system to {pve} 7, it is recommended that you | |
18 | manually install either `chrony`, `ntp` or `openntpd`. | |
19 | ||
20 | Using Custom NTP Servers | |
21 | ~~~~~~~~~~~~~~~~~~~~~~~~ | |
22 | ||
23 | In some cases, it might be desired to use non-default NTP | |
24 | servers. For example, if your {pve} nodes do not have access to the | |
25 | public internet due to restrictive firewall rules, you | |
26 | need to set up local NTP servers and tell the NTP daemon to use | |
27 | them. | |
28 | ||
29 | For systems using chrony: | |
30 | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
31 | ||
32 | Specify which servers `chrony` should use in `/etc/chrony/chrony.conf`: | |
33 | ||
34 | ---- | |
35 | server ntp1.example.com iburst | |
36 | server ntp2.example.com iburst | |
37 | server ntp3.example.com iburst | |
38 | ---- | |
39 | ||
40 | Restart `chrony`: | |
41 | ||
42 | # systemctl restart chronyd | |
43 | ||
44 | Check the journal to confirm that the newly configured NTP servers are being | |
45 | used: | |
46 | ||
47 | # journalctl --since -1h -u chrony | |
48 | ||
49 | ---- | |
50 | ... | |
51 | Aug 26 13:00:09 node1 systemd[1]: Started chrony, an NTP client/server. | |
52 | Aug 26 13:00:15 node1 chronyd[4873]: Selected source 10.0.0.1 (ntp1.example.com) | |
53 | Aug 26 13:00:15 node1 chronyd[4873]: System clock TAI offset set to 37 seconds | |
54 | ... | |
55 | ---- | |
56 | ||
57 | For systems using systemd-timesyncd: | |
58 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
59 | ||
60 | Specify which servers `systemd-timesyncd` should use in | |
61 | `/etc/systemd/timesyncd.conf`: | |
62 | ||
63 | ---- | |
64 | [Time] | |
65 | NTP=ntp1.example.com ntp2.example.com ntp3.example.com ntp4.example.com | |
66 | ---- | |
67 | ||
68 | Then, restart the synchronization service (`systemctl restart | |
69 | systemd-timesyncd`), and verify that your newly configured NTP servers are in | |
70 | use by checking the journal (`journalctl --since -1h -u systemd-timesyncd`): | |
71 | ||
72 | ---- | |
73 | ... | |
74 | Oct 07 14:58:36 node1 systemd[1]: Stopping Network Time Synchronization... | |
75 | Oct 07 14:58:36 node1 systemd[1]: Starting Network Time Synchronization... | |
76 | Oct 07 14:58:36 node1 systemd[1]: Started Network Time Synchronization. | |
77 | Oct 07 14:58:36 node1 systemd-timesyncd[13514]: Using NTP server 10.0.0.1:123 (ntp1.example.com). | |
78 | Oct 07 14:58:36 node1 systemd-timesyncd[13514]: interval/delta/delay/jitter/drift 64s/-0.002s/0.020s/0.000s/-31ppm | |
79 | ... | |
80 | ---- |