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@@ -60,17 +60,18 @@ of Kea.
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The following steps are needed to add new configuration backend (it is assumed
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that the modified component is DHCPv4. Similar approach applies to other
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-components):
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+components: DHCPv6 or D2):
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-# Modify AC_ARG_WITH(kea-config,...) macro in configure.ac
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-# Add your own AM_CONDITIONAL(CONFIG_BACKEND_FOO, ...) macro in configure.ac
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-# Add your own conditional AC_DEFINE(CONFIG_BACKEND_FOO, ...) invocation
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in configure.ac
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--# Modify sanity check in configure.ac to allow your configuration backend name.
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+-# Modify the sanity check in configure.ac to allow your configuration backend name.
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-# Modify src/bin/dhcp4/Makefile.am to include your own backend
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implementation (e.g. foo_controller.cc).
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-# Write your own implementation of isc::dhcp::ControlledDhcpv4Srv::init(),
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- isc::dhcp::ControlledDhcpv4Srv::init() and isc::dhcp::ControlledDhcpv4Srv::cleanup().
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+ isc::dhcp::ControlledDhcpv4Srv::init() and isc::dhcp::ControlledDhcpv4Srv::cleanup()
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+ and put it in foo_controller.cc
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Optionally you can also:
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@@ -83,20 +84,21 @@ Optionally you can also:
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The following are some considerations that shaped the design of the configuration
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backend framework.
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--# A new parameter called --with-kea-config will be implemented in the
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- configure script. It will allow the selection at compilation time of how the
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- servers will be configured. For the next 2-3 months (until around June 2014),
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- there will be two values: JSON (read from file) and BUNDY (use the BUNDY/BIND10 framework).
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- Once the file based configuration is implemented and the Kea team is ready to switch
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- (i.e. enough confidence, Forge tests updated for new configuration
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- mechanism), the Bundy/BIND10 framework will be removed from the Kea repository. Other projects
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- (e.g. Bundy) who want to maintain it, are advised to just revert the single
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- commit that will bring the Bundy framework back to their repositories.
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+-# A new parameter called --with-kea-config was implemented in the
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+ configure script. It allows the selection at compilation time of how the
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+ servers will be configured. Currently (June 2014),
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+ there are two values: JSON (the default, read configuration from a JSON file)
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+ and BUNDY (use the BUNDY/BIND10 framework). The Bundy/BIND10 framework was removed
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+ from the Kea repository. Other projects
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+ (e.g. Bundy) who want to maintain Bundy framework, are advised to maintain
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+ the framework in their repositories, import Kea modules and compile them
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+ with Bundy backend.
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This switchable backend concept is quite simple. There are just different
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- implementations of ControlledXSrv class, so it is a matter of compiling/linking
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+ implementations of ControlledXSrv class, each backend keeping its code
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+ in a separate file. It is a matter of compiling/linking
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one file or another. Hence it is easy to remove the old backend (and for
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- Bundy to keep it if they desire so). It is also easy for other
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- organizations to add and maintain their own backends (e.g. LDAP).
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+ external projects, like Bundy, to keep it if they desire so). It is also easy
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+ for other organizations to add and maintain their own backends (e.g. LDAP).
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-# Each backend must use the common code for configuration and command
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processing callbacks. They all assume that JSON formatted parameters are sent
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@@ -113,13 +115,15 @@ backend framework.
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-# A command handler needs to be added for reading the configuration from a
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file. Its main responsibility is to load the configuration and process
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it. The JSON backend must call that handler when starting up the server.
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+ This is implemented in configure() function in kea_controller.cc files
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+ in src/bin/dhcp4 and src/bin/dhcp6 directories.
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-# Extend the existing JSON parser. The current JSON parser in @ref
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isc::data::Element::fromJSON() needs to be extended to allow optional
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- preprocessing. For now that capability will simply remove whole-line
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+ preprocessing. For now that capability simply removes whole-line
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comments staring with the hash character, but it is expected to grow over
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time (in-line comments and file inclusions are the obvious envisaged
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- additions).
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+ additions). This is implemented in @ref isc::data::Element::fromJSONFile.
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-# Implement a common base class for the Kea4, Kea6, and D2 servers. Some
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operations will be common for all three components: logger initialization,
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@@ -128,16 +132,19 @@ backend framework.
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isc::dhcp::Dhcpv6Srv "Dhcpv6Srv" and the @ref isc::d2::D2Controller
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"D2Controller" classes can use. It is expected that the base class (@ref
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isc::dhcp::Daemon) will be a small one but will grow over time as the code is
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- unified.
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+ unified. This has been implemented in @ref isc::dhcp::Daemon.
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-# A way is needed to initialize stand-alone logging (i.e. each
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Kea component will initialize it on its own).
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--# The current format of the BIND10 configuration file, b10-config.db will be
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- retained as the configuration file format. This is slight change
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- from the BIND10 days, as then a subset of the configuration was received by
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- the daemon processes. To take a specific example, the following is how
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- b10-config.db looks today:
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+-# The current format of the BIND10 configuration file (BIND 10 stored its
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+ configuration in (installation directory)/var/bind10/b10-config.db) will be
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+ retained as the configuration file format. Its actual naming is now arbitrary
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+ and left up to the user (it is passed as a parameter to the -c command line
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+ option). From the implementation perspective, this is slight change
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+ from the BIND10 days, as back then a subset of the configuration was received by
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+ the daemon processes. Nowadays the whole configuration is pased. To take a
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+ specific example, the following is how b10-config.db looks today:
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@code
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{
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"Init": { ... }
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@@ -186,4 +193,7 @@ backend framework.
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- this could also decide if D2 should still be running or not, and react accordingly (post 0.9)
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-# Stop the processes in an orderly fashion
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-# Perhaps return status of each process
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+
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+This script has been implemented in src/bin/keactl/keactl.
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+
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*/
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