SLE 11 Network Time Protocol (NTP) upgrade from 4.2.4 to 4.2.8 requires that existing NTP configuration options be updated and verified

This document (7018076) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 1 (SLES 11 SP1)
SUSE Linux Enterprise Server 11 Service Pack 2 (SLES 11 SP2)
SUSE Linux Enterprise Server 11 Service Pack 3 (SLES 11 SP3)
SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)

Situation

The upgrade from Network Time Protocol (NTP) version 4.2.4 to 4.2.8 results in Application Binary Interface (ABI) changes within components of the NTP package that may affect existing direct usage e.g. familiarity with manual entered commandlines and/or custom authored scripts using NTP components. Due to the ABI changes there is a risk that these may fail after the NTP upgrade from 4.2.4 to 4.2.8.

Resolution

Performing the upgrade from the NTP 4.2.4 package to the NTP 4.2.8 package requires that all existing usage, configuration, custom scripts and command options be verified and if needed updated to be compliant with the NTP 4.2.8 ABI.

For example the sntp version 4.2.8 option "-ddd" is similar to the "-W" option from version 4.2.4. Since the "-V" option from version 4.2.4 is less detailed than the "-W" option then the "-dd" option for version 4.2.8 is the closest option compared to the description provided for the "-V" option from version 4.2.4. Therefore, the "-d" option from version 4.2.8 is the closest option if compared to the description of the "-v" option from version 4.2.4. From the sntp man page comparisons, -v|-V|-W in 4.2.4 is similar in purpose to -d|-dd|-ddd respectively in version 4.2.8.

For any given tool from the NTP package a comparison of that tool between the NTP 4.2.4 and NTP 4.2.8 packages is necessary. This can be done using the installed man pages, program help or other published documentation (e.g. at http://doc.ntp.org/ where there is a version by version document archive).

Cause

Since NTP version 4.2.4 is no longer maintained upstream and due to significant ongoing security maintenance on only NTP version 4.2.8 the NTP package version was upgraded from NTP 4.2.4 to NTP 4.2.8. Due to the scope of the changes between the two versions, incorporating the security fixes and changes in the 4.2.4 version would have been complex and risked reliability, stability and security. Updating the version to 4.2.8 also permits on-going security updates to be obtained from a single source.

Additional Information

An effective approach for all other NTP commands is to use methods similar to those shown for sntp above. While it may be found that a given NTP version 4.2.4 commandline, configuration or other option has an equivalent or identical option in NTP version 4.2.8 some care should be taken where there is output or behaviour generated as a result of the use of the option(s). Some options may now result in different behaviour such as producing different output (even as simple as spelling correction) which can result in the failure of any custom script(s) or other material based on parsing output or behaviour of NTP package components.

It should be verified that any custom configuration and / or scripts and commands still react as desired in all cases that can be expected to be experienced, i.e. custom scripts and similar items can be upgraded to support the NTP 4.2.8 ABI without removing their support for the NTP 4.2.4 ABI leaving them deployable on hosts using either NTP package version.

Disclaimer

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