+Build collectd-6
+^^^^^^^^^^^^^^^^
+
+The barometer-collectd-experimental Dockerfile can be used to build
+collectd-6.0, which is currently under development. In order to do this, the
+``COLLECTD_FLAVOR`` build arg can be passed to the docker build command.
+The optional ``COLLECTD_PULL_REQUESTS`` arg can be passed as well, to test
+proposed patches to collectd.
+
+.. code:: bash
+
+ $ cd <BAROMETER_REPO_DIR>
+ $ sudo docker build -t anuket/barometer-collectd-6 \
+ --build-arg COLLECTD_FLAVOR=collectd-6 \
+ --build-arg COLLECTD_PULL_REQUESTS=1234,5678 \
+ --network=host -f docker/barometer-collectd-experimental/Dockerfile .
+
+The instructions for running the collectd-6 container are the same as for the
+collectd-experimental container.
+
+There are a few useful build args that can be used to further customise the
+collectd-6 build:
+
+* **COLLECTD_CONFIG_CMD_ARGS**
+ For testing with new plugins for collectd-6, as un-ported plugins are
+ disabled by default.
+ This new option lets the ./configure command be run with extra args,
+ e.g. --enable-cpu --enable-<my-newly-ported-plugin>, which means that
+ plugin can be enabled for the PR that is being tested.
+
+* **COLLECTD_TAG**
+ This overrides the default tag selected by the flavors, and allows checking
+ out out an arbitrary branch (e.g. PR branch instead of using the
+ ``COLLECTD_PULL_REQUESTS`` arg, which rebases each PR on top of the
+ nominal branch.
+ To check out a PR, use the following args with the docker build command:
+ ``--build-arg COLLECTD_TAG=pull/<PR_ID>/head``
+