New units of a designate-bind cluster cannot resolve old records

[Liam Young]

If a unit is added to a designate-bind application running focal then the new unit will not be able to resolve existing records. This appears to be due to nzd files being omitted when the new /var/cache/bind dir is seeded from an existing unit.

[Liam Young (gnuoy)]

It looks like the focal version of named is compiled with lmdb support where as the bionic version is not. Hence the change in behaviour:

# lsb_release -c; named -V | grep -ohE 'with-lmdb|without-lmdb'
Codename: bionic
without-lmdb
# lsb_release -c; named -V | grep -ohE 'with-lmdb|without-lmdb'
Codename: focal
with-lmdb

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/733055

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/733055
Committed: https://git.openstack.org/cgit/openstack/charm-designate-bind/commit/?id=02f667ac166dc8d6e1eeb8b0d130b6259abc01d2
Submitter: Zuul
Branch: master

commit 02f667ac166dc8d6e1eeb8b0d130b6259abc01d2
Author: Liam Young <email address hidden>
Date: Wed Jun 3 07:20:25 2020 +0000

    Update files used to seed new bind units

    It looks like the focal version of named is compiled with lmdb
    support where as the bionic version is not. This means that on
    Focal+ zone information is stored in a nzd file rather than
    nzf. This change ensure that nzd files are also used to seed new
    units.

    Change-Id: Ib1954ec01d78518da064b0912b91643c153d543e
    Closes-Bug: #1881532

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/20.05
Review: https://review.opendev.org/733600