Batch settings are not configurable

[Rodrigo Barbieri]

Ceilometer allows batch settings to be configured for the notification agent [0] and poller [1], thus having messages containing an optimal amount of messages.

[1] prevents [2] as of Rocky, but also creates problem [3] where number measures aggregated can be too low at the same time and could be increased to reduce the flood of API calls to gnocchi.

This option should be configurable to optimize the amount of load for the cloud.

[0] https://github.com/openstack/ceilometer/blob/f8992d40a135188a9d89c86f78868d340f3a1b96/ceilometer/notification.py#L46
[1] https://github.com/openstack/ceilometer/blob/93baa22645d5ba64fa8b1d44cc97525437312256/ceilometer/polling/manager.py#L69
[2] https://bugs.launchpad.net/ceilometer/+bug/1770310
[3] https://storyboard.openstack.org/#!/story/2007864

[Rodrigo Barbieri (rodrigo-barbieri2010)]

patches:
https://review.opendev.org/738222
https://review.opendev.org/738225

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/738222
Committed: https://git.openstack.org/cgit/openstack/charm-ceilometer/commit/?id=740cac6571a1a27f0c84fc8567e2a36e09d9aefe
Submitter: Zuul
Branch: master

commit 740cac6571a1a27f0c84fc8567e2a36e09d9aefe
Author: Rodrigo Barbieri <email address hidden>
Date: Fri Jun 26 12:05:19 2020 -0300

    Add polling-batch-size config option

    Samples collected can be batched together,
    consequently increasing or reducing the
    amount of API calls and body data
    sent to the configured publisher.

    This config is available since Rocky,
    adding the config option to allow its
    tuning.

    Change-Id: I0e3f756aa0305d3a96e21c7498d6a56208c51007
    Closes-bug: #1885190

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/738225
Committed: https://git.openstack.org/cgit/openstack/charm-ceilometer-agent/commit/?id=2aace2fb697b17129d63bcf88dc8eae180e235af
Submitter: Zuul
Branch: master

commit 2aace2fb697b17129d63bcf88dc8eae180e235af
Author: Rodrigo Barbieri <email address hidden>
Date: Fri Jun 26 12:08:52 2020 -0300

    Receive polling-batch-size config

    Samples collected can be batched together,
    consequently increasing or reducing the
    amount of API calls and body data
    sent to the configured publisher.

    This config is available since Rocky,
    receiving the value from ceilometer-charm
    to allow its tuning.

    Change-Id: I986073fdacd750cf96d662abf1d58844479c25ba
    Closes-bug: #1885190