[Kea-announce] Kea 1.8.1, a new stable production release of Kea, is now available

Michael McNally mcnally at isc.org
Thu Nov 12 21:44:58 UTC 2020

Internet Systems Consortium is pleased to announce the release of Kea 1.8.1.

Kea releases are divided into two branch sequences:

1)  A current stable branch (currently 1.8.x) which receives only important
     bug fixes and is otherwise feature-stable, and

2)  An experimental development branch (currently 1.9.x) where new features
     are added and made available for testing during development, before eventually
     being included in the next stable release branch.

Kea 1.8.1 is the latest release in the current stable branch.

The most important inclusion in this release is a fix for a race condition
that could interfere with HA.  This fix, which was already included in the
development branch, has been backported to the stable branch and is recommended
for operators who are using High Availability in their production Kea installation.

Michael McNally
ISC Support


# Kea 1.8.1, Nov 12th 2020, Release Notes

Welcome to Kea 1.8.1, the first maintenance release of the 1.8 series.
Kea is a DHCP implementation developed by Internet Systems Consortium,
Inc. that features fully functional DHCPv4 and DHCPv6 servers, a dynamic
DNS update daemon, a Control Agent (CA) that provides a REST API to
control the DHCP and DNS update servers, an example shell client to
connect to the CA, a daemon that is able to retrieve YANG configuration
and updates from Sysrepo, and a DHCP performance-measurement tool. Both
DHCP servers support server discovery, address assignment, renewal,
rebinding, release, decline, information request, DNS updates, client
classification, and host reservations. The DHCPv6 server also supports
prefix delegation. Lease information is stored in a CSV file by default;
it can optionally be stored in a MySQL, PostgreSQL, or Cassandra
database instead. Host reservations can be stored in a configuration
file, or in a MySQL, PostgreSQL, or Cassandra database. They can also be
retrieved from a RADIUS server, although this functionality is somewhat
limited. Kea DHCPv4 and DHCPv6 daemons provide support for YANG models,
which are stored in a Sysrepo datastore and can be configured via the
NETCONF protocol.

This is a maintenance release. If you are interested in the latest
development releases with new features, please look at the development
1.9.x series.

The text below references issue numbers. For more details, visit the Kea
GitLab page at https://gitlab.isc.org/isc-projects/kea/issues.

The following bug fixes were implemented since version 1.8.0:

1. **Fix the lease commands DB backend**. Kea 1.8 introduced
multi-threading which, by its parallel nature, introduces races where
two or more threads attempt to use the same lease. Kea introduced a
mechanism to detect those races, by checking the value of the old lease
expiration time that is currently stored in the database. This mechanism
works well for threads running on the same machine; however, under
certain conditions it could fail if the lease update was triggered
externally using lease commands. Unfortunately, one of the primary use
cases of the lease updates commands is the High Availability (HA)
feature. This fix was originally released in Kea 1.9.1 and was
backported to 1.8.1. #1488, #1434

2. **DHCP-DDNS fails to create an A record**. kea-dhcp4 now correctly
updates DNS when a client returns for a lease after the lease has
expired. Before this fix, the server removed the entries when the lease
expired but then failed to add them when the client reacquired the lease
unless the hostname (or FQDN) changed. This change also eliminates
redundant DNS removals when expired leases are reclaimed and given to
different clients. #1409, #1419

3. **Remove multi-threading warning**. This is a purely cosmetic change.
During the development of the multi-threading capability in Kea, a
warning log message was added to caution against the experimental nature
of MT. With the release of stable 1.8.0, the MT is no longer considered
experimental and the now-obsolete log message has been removed. This fix
addresses this small problem. #1431, #1435

## License
This version of Kea is released under the Mozilla Public License,
version 2.0.


The premium and subscriber-only hooks libraries are provided under the
terms of an End User License Agreement.

## Download

Pre-built ISC packages for current versions of the most popular Linux
operating systems are available at:


The Kea source and PGP signature for this release may be downloaded from:


The signature was generated with the ISC code signing key, which is
available at:


ISC provides detailed documentation, including installation instructions
and usage tutorials, in the Kea Administrator Reference Manual.
Documentation is included with the installation or via
https://kb.isc.org/docs/kea-administrator-reference-manual in HTML,
plain text, or PDF formats. ISC maintains a public open source code
tree, wiki, issue tracking system, milestone planner, and roadmap at

Limitations and known issues with this release can be found at

We ask users of this software to please let us know how it worked for
you and what operating system you tested on. Feel free to share your
feedback on the Kea Users mailing list
(https://lists.isc.org/mailman/listinfo/kea-users).  We would also like
to hear whether the documentation is adequate and accurate. Please open
tickets in the Kea GitLab project for bugs, documentation omissions and
errors, and enhancement requests. We want to hear from you even if
everything worked.

## Support

Professional support for Kea is available from ISC. We encourage all
professional users to consider this option; Kea maintenance is funded
with support subscriptions. For more information on ISC's Kea and DHCP
software support see https://www.isc.org/support/.

Free best-effort support is provided by our user community via a mailing
list. Information on all public email lists is available at
https://www.isc.org/community/mailing-list. If you have any comments or
questions about working with Kea, please share them to the Kea Users
list (https://lists.isc.org/mailman/listinfo/kea-users). Bugs and
feature requests may be submitted via GitLab at

## Changes

The following summarizes changes and important upgrade notes since the

1801.   [build]         razvan
	Library version numbers bumped for Kea 1.8.1 stable release
	(Gitlab #1530)

1800.	[bug]		razvan
	Fixed lease update when using HA and lease_cmds hooks with
	database backend. Previously, HA updates were rejected because
	the database backend rejects operations on the lease if the old
	expiration time is different than what it is already stored, to
	act as a protection mechanism for parallel updates from several
	threads or processes.
	(Gitlab #1434,#1488)

1799.	[bug]		tmark
	kea-dhcp4 now correctly updates DNS when a client
	returns for a lease after the lease has expired. Prior
	to this, the server would remove the entries but then
	fail to add them unless the hostname (or FQDN) changed.
	This change also eliminates redundant DNS removals when
	expired leases are reclaimed and given to different clients.
	(Gitlab #1419,#1409)

1798.	[func]	razvan,tmark
	Removed "Multithreading is experimental" warning log message
	from kea-dhcp4 and kea-dhcp6 servers.
	(Gitlab #1435,#1431)

Thank you again to everyone who assisted us in making this release

We look forward to receiving your feedback.

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