# Kea 1.7.1, October 30th 2019, Release Notes Welcome to Kea 1.7.1, the second monthly development release of Kea. This release is the next step towards having fully multi-threaded DHCP servers, which will eventually become available as 1.8.0. This is a development release. Use with caution! Development releases are not recommended for production use. Changes introduced in this version: 1. **Fine grained DNS Updates**. Prior to 1.7.1, Kea allowed you to configure DNS Update parameters globally. Starting with this release, it is possible to specify many DNS behavioral parameters at the global, shared network and subnet levels. In particular, it is possible to specify whether to send the updates or not (ddns-send-updates), control whether to sanity check the client update (ddns-replace-client-name, hostname-char-set, hostname-char-replacement), replace (ddns-generated-prefix) or expand it (ddns-qualifying-suffix) on a per shared network or subnet basis. This should give users much better flexibility over what updates are done and when (#35). 2. **Flexible options**. Prior to 1.7.1, Kea allowed to you to specify option values in a fixed way. It was possible to specify option values on per shared network, subnet, class or host, but the values were always constant. Sometimes it is useful to generate the option values based on certain criteria, such as incoming option values, the client's MAC address or some other condition. This is now possible with a new open source hook called Flexible option. For details, see a new section "Flexible Option for Option value settings" in the Kea Administrator Reference Manual (#219). 3. **New API command: reservation-get-by-hostname**. Our premium hook *host_cmds* has been extended with a new API command reservation-get-by-hostname. It allows you to search existing hosts reservations for those reserved with a specific hostname. This is useful if you want to check if a certain hostname is reserved for anyone or not. Also, it lets you to find a reservation if the only information available is the hostname, but the typical MAC addresses or reserved IPv4/IPv6 address is unknown. (#392) 4. **New API commands to search for host reservations**. Our premium hook *host_cmds* has been extended with the ability to search for host reservations using MAC address, client-id, hostname or DUID. New commands (lease4-get-by-client-id, lease4-get-by-hostname, lease4-get-by-hw-address, lease6-get-by-duid, lease6-get-by-hostname) are now available. One particularly useful feature of those new commands is that they don't require specifying the subnet-id and they search through all existing reservations (#393). 5. **New API to trigger Config Backend update**. Kea 1.6.0 introduced the config backend mechanism that allows storing configuration in a database that is periodically polled to retrieve configuration changes. This allows for completely autonomous deployment of new configuration changes, but has the downside of needless DB load when there are no changes. A new command config-backend-pull has been introduced to the subscriber only *cb_cmds* hook that lets you trigger the configuration retrieval on demand. It can be used with the regular periodic updates (i.e. when you don't want to wait and the configuration should be retrieved immediately) or you can disable the periodic checks altogether and trigger the retrieval only when needed (#904). 6. **Compilation options**. This is a small, but useful feature. Kea now remembers the compilation options it was compiled with. Please use -W command line switch to retrieve parameters passed to configure script (#869). 7. **Experimental packages for Alpine and CentOS 8**. ISC has prepared packages for Alpine Linux and recently published CentOS8. Since we did not have enough resources to test them yet, they're not publicly available yet. However, if you are interested, please get in touch and we'll be happy to provide them for early adopters. The packages are expected to be publicly available with the next development release (#934, #772). 8. **Multi-threading improvements**. While there are no clearly user-visible changes yet, our team continues its work towards making Kea fully multi-threaded one day. This month we did many code cleanups (#497, #907, #918, #919, #930) and preparatory work (#962). ## Changes to Release Model The Kea project has been in development for several years now, and it 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, including some new powerful, but difficult to implement, features. As a result, we decided to change the release cycle. Starting from 1.6.0, there are two series of releases: stable and development. Stable releases are what you would expect: stable, released infrequently, without new features or significant changes, very well-tested. Those can be identified by the middle version number being even. The current stable release is 1.6.0. If we discover important bugs that require fixing, we may release 1.6.1, 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. Our team continues development of new features. In particular, we're tackling the difficult problem of being able to use all available CPU cores simultaneously. The multi-threading implementation is a complex task and it is unknown how long it will take before the solution is stable and ready for production environment. At the same time, we continue to receive a stream of requests for small features and bug fixes. We don't want to force users to wait half a year or more for the fixes and features that are already done. Therefore, we have decided to start issuing development releases on a monthly basis. Those are slightly less well-tested and may have features that are not complete; a good example may be multi-threading. It is possible that one of the next releases will provide a configuration knob to specify the number of threads, but the actual code won't be extended yet to spawn those threads. The development releases can be easily identified by the middle version number being odd; for example, 1.7.1 is a development release. In November 2019 we will release 1.7.2, the next development version. Once 1.8.0 is out, we will continue our development work on 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/v1/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 fully 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/downloads The signature was generated with the ISC code signing key which is available at: https://www.isc.org/pgpkeys 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 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 (1.7.1). 1681. [func] fdupont Added new command config-backend-pull which forces the server to immediately poll the configuration updates from the configuration backend (Gitlab #904) 1680. [bug,build] Kristoffer Larsen A bug in Makefile has been fixed. The changes made to src/lib/dhcpsrv/alloc_engine_messages.mes are now picked up properly. (Gitlab #752) 1679. [func] fdupont Added new commands to the lease_cmds hooks library to search for leases by hardware address, client-id, DUID and hostname. Now hostnames are stored in lower case within the lease database. (Gitlab #393) 1678. [build] fdupont The arguments passed to configure are now stored and are available using -W command line option. (Gitlab #869) 1677. [doc] wlodek Sample configs now all use the same paths for control sockets. (Gitlab #795) 1676. [func] fdupont A new hook - flex-option - has been developed. It allows setting up DHCPv4 and DHCPv6 option values dynamically, using expression. This capability is very useful when you want to generate option value procedurally. For details, see new section "Flexible Option for Option value settings" in the Kea Administrator Reference Manual. (Gitlab #219,!523, git 2bf854c029b9b07ee6161bc1fcb4dfdc9846ee42) 1675. [func] fdupont Both DHCPv4 and DHCPv6 can now listen on and send responses to a custom UDP port, as specified with the -p command line option. This capability is mostly useful for testing. (Gitlab #677,!548, git 47e709fb7b89464d4473e8c7cb138f539042d68b) 1674. [perf] fdupont Added a Multi Threading Manager singleton class in the util library. (Gitlab #962,!566, git 66b090e54b45bdeefda266ddd62e42b46ed48d1d) 1673. [bug] tmark Fixed a bug introduced in Kea 1.6.0 (see #539) that caused kea-dhcp4 and kea-dhcp6 to discard inbound packets containing string options that consist solely of nulls. The servers will now quietly omit empty or all-null string options from inbound packets. (Gitlab #900,!561, git c75a7c10bde74f59d481a7717b4e03b9cb2268a6) 1672. [build] fdupont Deprecated bind1st and bind2nd templates were replaced with lambda expressions or plain bind templates. (Gitlab #919,!521, git b12fa3374454c9c0d749557d5532aab55dbc58d9) 1671. [bug] tmark Corrected an issue in kea-dhcp6 where the server would fail to extend the expiry of a existing dynamic lease assigned to client with host reservation. (Gitlab #754,!558, git c223380012b82c93292528b593002c2b80b5361b) 1670. [func] fdupont Added searches for host reservations by hostname and by hostname and subnet. (Gitlan #392,!529, git 50068ada6b277c9251de9062501d8c478a8f5529) 1669. [func] tmark Rather than within the 'dhcp-ddns' section, DDNS behavioral parameters may now be specified at global, shared-network, and subnet scopes. Implemented for both kea-dhcp4 and kea-dhcp6. Not yet supported by Config Backend or Netconf. (Gitlab #35,!517, git 49ce6286f5d00f99c1c890f12cbc0fd633c9dbf6) 1668. [build] fdupont The Kea util thread library was removed. (Gitlab #907,!519, git 1b27dc52aae23753643461086f0950b125bf9c93) 1667. [build] fdupont The availability of C++11 thread, mutex, condition variable and atomic libraries is now checked by ./configure. (Gitlab #918,!520, git baf4097520c1cd38366ee4f33a95dde040906e9e) 1666. [doc] tmark Added note in ARM about manually admining cb data being possible but not supported. (Gitlab #917,!518, git f242e5c2e0e14331172671477dce3a6597691b55) Thank you again to everyone who assisted us in making this release possible. We look forward to receiving your feedback.