# Kea 1.7.8, May 27th 2020, Release Notes Welcome to Kea 1.7.8, a monthly development release of Kea. As with any other development release, use this with caution. Development releases are not recommended for production use. The most significant changes introduced in this version are: 1. **High Availability multithreading**. The HA hook now has experimental mulit-threading support. 2. **HA backup non blocking**. Active servers no longer wait for lease update acknowledgments from backup servers. 3. **HA passive backup mode** The new passive-backup mode allows for running a single active server with a number of backup servers. 4. **Multithreading support improved**. We will be releasing Kea 1.8.0 when the multithreading is complete and stable. This release takes another step towards that goal. 5. **Congestion-control disabled for multithreading**. Multi-threading and congestion handling are incompatible. When both are enabled by a configuration the dhcp-queue-control is silently disabled, when packet-queue-size is not 0 and the multi-threading packet queue is full the oldest packet is dropped to make room for a new received one. ## Release Model The Kea project has a significant production deployment base with users who are looking for stability, rather than a constant stream of new "bleeding-edge" features. At the same time, we want to continue developing the software and add some new powerful, but difficult-to-implement, features. To meet both of these requirements we have both Stable and Development branches. Stable releases are what you would expect: stable, released infrequently, without new features or significant changes, very well-tested. These can be identified by an even-numbered major version number. The current stable release is 1.6.2, with a major version of 1.6, and minor version 2. If we discover important bugs that require fixing, we may release 1.6.3, but that will be determined on a case-by-case basis. The next major stable version will be 1.8.0, followed by 2.0.0 in the future. Development releases can be easily identified by an odd major version number: for example, 1.7.7 is a development release. In June 2020 we expect to release 1.7.8, the next development version. Once 1.8.0 is out, we will continue our development work with 1.9.0, then 1.9.1, and so on. Our goal is to make the development release available on the last Wednesday of each month. There may be exceptions (such as during holidays), but that's the general plan. We encourage users to test the development releases and report back their findings. For more details on the plan, see ISC's Software Support Policy at https://kb.isc.org/docs/aa-00896. ## Kea overview 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 text references issue numbers. For more details, visit the Kea GitLab page at https://gitlab.isc.org/isc-projects/kea/issues. ## License This version of Kea is released under the Mozilla Public License, version 2.0. https://www.mozilla.org/en-US/MPL/2.0 The premium and subscriber-only hook libraries are provided in source code form, under the terms of an End User License Agreement (you will get the source code that you can modify freely, but you are not permitted to redistribute it). ## Download Pre-built ISC packages for current versions of the most popular Linux operating systems are available at: https://cloudsmith.io/~isc/repos/ The Kea source and PGP signature for this release may be downloaded from: https://www.isc.org/download The signature was generated with the ISC code signing key which is available at: https://www.isc.org/pgpkey ISC provides detailed documentation, including installation instructions and usage tutorials, in the Kea Administrator Reference Manual. Documentation is included with the installation, at https://kea.readthedocs.io/en/latest/, 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, a wiki, an issue tracking system, milestone planning, and a roadmap at https://gitlab.isc.org/isc-projects/kea. Limitations and known issues with this release can be found at https://gitlab.isc.org/isc-projects/kea/wikis/known-issues-list. 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). Also we would 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 development and maintenance are 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 https://gitlab.isc.org/isc-projects/kea/issues. ## Changes The following summarizes changes and important upgrade notes since the previous release (1.7.7). ``` 1750. [func] razvan Refactored HooksManager so that no lazy initialization is possible from dhcp processing functions. The function getHooksManager is now private. (Gitlab #1227) 1749. [func] fdupont When the version is a development (vs. stable) one (second number is odd, e.g. in 1.7.x) a server or agent logs a warning to dissuade use in production. (Gitlab #1184) 1748. [func] marcin Added two extensions to the HA hooks library. Firstly, the active servers no longer wait for the lease update acknowledgments from the backup servers. Secondly, the new passive-backup mode allows for running a single active server with a number of backup servers. (Gitlab #999) 1747. [bug] fdupont Multi-threading and congestion handling were made incompatible: when both are enabled by a configuration the dhcp-queue-control is silently disabled, when packet-queue-size is not 0 and the multi-threading packet queue is full the oldest packet is dropped to make room for a new received one. (Gitlab #1173) 1746. [bug] fdupont lease4-add and lease6-add commands now return an error when the lease already exists. (Gitlab #1170) 1745. [bug] fdupont Made state model and external sockets thread safe. (Gitlab #1095) 1744. [func] razvan Stopping packet processing when changing or reloading configuration. (Gitlab #1188) ``` Thank you again to everyone who assisted us in making this release possible. We look forward to receiving your feedback.