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authorChristian Breunig <christian@breunig.cc>2024-01-21 20:48:33 +0100
committerChristian Breunig <christian@breunig.cc>2024-01-21 20:48:45 +0100
commit5447c0509f5160db72065aaeac078639486aee68 (patch)
tree6ffe276a0533182a6b2f505ff0d78170d6164207 /docs
parentf995bfe32c98fd4faaec0cbec36cd6d1d21b1bf9 (diff)
downloadvyos-documentation-5447c0509f5160db72065aaeac078639486aee68.tar.gz
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ntp: T5692: add support to configure leap second behavior
(cherry picked from commit 2443622964b476bfbcf88b05322fd27b55406fad)
Diffstat (limited to 'docs')
-rw-r--r--docs/configuration/service/ntp.rst31
1 files changed, 30 insertions, 1 deletions
diff --git a/docs/configuration/service/ntp.rst b/docs/configuration/service/ntp.rst
index 08be047c..e7ee392b 100644
--- a/docs/configuration/service/ntp.rst
+++ b/docs/configuration/service/ntp.rst
@@ -81,4 +81,33 @@ Configuration
.. cfgcmd:: set service ntp vrf <name>
- Specify name of the :abbr:`VRF (Virtual Routing and Forwarding)` instance.
+ Specify name of the :abbr:`VRF (Virtual Routing and Forwarding)` instance.
+
+.. cfgcmd:: set service ntp leap-second [ignore|smear|system|timezone]
+
+ Define how to handle leaf-seonds.
+
+ * `ignore`: No correction is applied to the clock for the leap second. The
+ clock will be corrected later in normal operation when new measurements are
+ made and the estimated offset includes the one second error.
+
+ * `smear`: When smearing a leap second, the leap status is suppressed on the
+ server and the served time is corrected slowly by slewing instead of
+ stepping. The clients do not need any special configuration as they do not
+ know there is any leap second and they follow the server time which
+ eventually brings them back to UTC. Care must be taken to ensure they use
+ only NTP servers which smear the leap second in exactly the same way for
+ synchronisation.
+
+ * `system`: When inserting a leap second, the kernel steps the system clock
+ backwards by one second when the clock gets to 00:00:00 UTC. When deleting
+ a leap second, it steps forward by one second when the clock gets to
+ 23:59:59 UTC.
+
+ * `timezone`: This directive specifies a timezone in the system timezone
+ database which chronyd can use to determine when will the next leap second
+ occur and what is the current offset between TAI and UTC. It will
+ periodically check if 23:59:59 and 23:59:60 are valid times in the
+ timezone. This normally works with the right/UTC timezone which is the
+ default
+