Running Kea without BIND10/Bundy framework

[Tomek Mrugalski]

Folks,

Ticket #3400 has been merged to master, so that means that Kea6 is now
able to run without python framework. This brings in a couple of
significant changes. There are tickets planned for proper documentation
update, but until those are done, you can use this mail as a sort of
cheat-sheet. Similar changes for Kea4 are in progress. D2 will follow soon.

1. To compile Kea in stand-alone mode:

./configure --with-kea-config=JSON

The new parameter specifies how Kea obtains its configuration. Two
values are available: Bundy (former BIND10 - Kea tries to connect to
Bundy framework using control session, msgq and all that stuff) or JSON
(Kea is reading its configuration from a JSON file). For the time being,
the default is Bundy, but it will swich to JSON in the next couple weeks
(definitely well before 0.9 is released).

2. After the code has been built, run Kea6:

./b10-dhcp6 -c your-config-file.json

There is one example in doc/examples/kea6/several-subnets.json

3. You can use -v option to switch Kea into verbose mode and it will
print debug messages.

4. The JSON file is how Kea (or BIND10) stored its configuration
internally. The easiest way to migrate from Kea 0.8 or earlier is to
copy your configuration that is stored in
(installdir)/var/bind10/b10-config.db. For now, Kea6 interprets only
"Dhcp6" sub-tree in it. Kea will soon also interpret "Logging" sub-tree,
but for the time being everything is printed on stdout. This will be
done in #3427.

If you really want to write your own JSON files now, you can look at
src/bin/dhcp6/dhcp6.spec file that defines the syntax.

5. There is currently no way to shutdown gracefully or reread
configuration. That will be done in ticket #3406.

6. Proper documentation update where this is all described will be done
in #3418.

Tomek