cinder fails because of trying to downgrade librados2 librbd1

[panic!]

When installing rocky on ubuntu 18.04 with ceph backend cinder fails because it wants to downgrade librados2 librbd1.

TASK [ceph_client : Update Apt cache] *****************************************************************************************************************
changed: [host1]

TASK [ceph_client : include_tasks] ********************************************************************************************************************
included: /etc/ansible/roles/ceph_client/tasks/ceph_install.yml for host1

TASK [ceph_client : Install ceph packages] ************************************************************************************************************
FAILED - RETRYING: Install ceph packages (5 retries left).
FAILED - RETRYING: Install ceph packages (4 retries left).
FAILED - RETRYING: Install ceph packages (3 retries left).
FAILED - RETRYING: Install ceph packages (2 retries left).
FAILED - RETRYING: Install ceph packages (1 retries left).
fatal: [host1]: FAILED! => {"attempts": 5, "cache_update_time": 1549929780, "cache_updated": false, "changed": false, "msg": "'/usr/bin/apt-get -y -o \"Dpkg::Options::=--force-confdef\" -$
 \"Dpkg::Options::=--force-confold\" install 'ceph-common' 'python-ceph'' failed: E: Packages were downgraded and -y was used without --allow-downgrades.\n", "rc": 100, "stderr": "E: Pa$
kages were downgraded and -y was used without --allow-downgrades.\n", "stderr_lines": ["E: Packages were downgraded and -y was used without --allow-downgrades."], "stdout": "Reading package
lists...\nBuilding dependency tree...\nReading state information...\nThe following package was automatically installed and is no longer required:\n grub-pc-bin\nUse 'apt autoremove' to rem$
ve it.\nThe following additional packages will be installed:\n libbabeltrace1 libcephfs2 libdw1 libgoogle-perftools4 liblttng-ust-ctl4\n liblttng-ust0 liboath0 librados2 libradosstriper1 $
ibrbd1 librgw2\n libtcmalloc-minimal4 liburcu6 python-asn1crypto python-cephfs python-certifi\n python-cffi-backend python-chardet python-cryptography python-enum34\n python-idna python-$
paddress python-openssl python-prettytable python-rados\n python-rbd python-requests python-rgw python-six python-urllib3\nSuggested packages:\n ceph-base ceph-mds python-cryptography-doc
python-cryptography-vectors\n python-enum34-doc python-openssl-doc python-openssl-dbg python-socks\n python-ntlm\nThe following NEW packages will be installed:\n ceph-common libbabeltrac$
1 libcephfs2 libdw1 libgoogle-perftools4\n liblttng-ust-ctl4 liblttng-ust0 liboath0 libradosstriper1 librgw2\n libtcmalloc-minimal4 liburcu6 python-asn1crypto python-ceph python-cephfs\n
python-certifi python-cffi-backend python-chardet python-cryptography\n python-enum34 python-idna python-ipaddress python-openssl python-prettytable\n python-rados python-rbd python-reque$
ts python-rgw python-six python-urllib3\nThe following packages will be DOWNGRADED:\n librados2 librbd1\n0 upgraded, 30 newly installed, 2 downgraded, 0 to remove and 2 not upgraded.\n", "$
tdout_lines": ["Reading package lists...", "Building dependency tree...", "Reading state information...", "The following package was automatically installed and is no longer required:", " $
rub-pc-bin", "Use 'apt autoremove' to remove it.", "The following additional packages will be installed:", " libbabeltrace1 libcephfs2 libdw1 libgoogle-perftools4 liblttng-ust-ctl4", " li$
lttng-ust0 liboath0 librados2 libradosstriper1 librbd1 librgw2", " libtcmalloc-minimal4 liburcu6 python-asn1crypto python-cephfs python-certifi", " python-cffi-backend python-chardet pyth$
n-cryptography python-enum34", " python-idna python-ipaddress python-openssl python-prettytable python-rados", " python-rbd python-requests python-rgw python-six python-urllib3", "Suggest$
d packages:", " ceph-base ceph-mds python-cryptography-doc python-cryptography-vectors", " python-enum34-doc python-openssl-doc python-openssl-dbg python-socks", " python-ntlm", "The foll
owing NEW packages will be installed:", " ceph-common libbabeltrace1 libcephfs2 libdw1 libgoogle-perftools4", " liblttng-ust-ctl4 liblttng-ust0 liboath0 libradosstriper1 librgw2", " libtc
malloc-minimal4 liburcu6 python-asn1crypto python-ceph python-cephfs", " python-certifi python-cffi-backend python-chardet python-cryptography", " python-enum34 python-idna python-ipaddres
s python-openssl python-prettytable", " python-rados python-rbd python-requests python-rgw python-six python-urllib3", "The following packages will be DOWNGRADED:", " librados2 librbd1", "
0 upgraded, 30 newly installed, 2 downgraded, 0 to remove and 2 not upgraded."]}

RUNNING HANDLER [os_cinder : Stop services] ***********************************************************************************************************
changed: [host1] => (item={u'start_order': 2, u'group': u'cinder_volume', u'execreloads': u'/bin/kill -HUP $MAINPID', u'service_name': u'cinder-volume', u'execstarts': u'/openstack/venvs/c
inder-18.1.3/bin/cinder-volume', u'init_config_overrides': {}, 'service_key': u'cinder-volume'})

This is fixed in this patch:

https://review.openstack.org/#/c/636115/

cherrypicking this fix solves the problem also for rocky.

[Jonathan Rosser (jrosser)]

Rocky branch currently holds the download.ceph.com packages back to luminous release during tests so there is no conflict with the UCA packages.

Restoring this patch https://review.openstack.org/#/c/613780/ as a way of verifying the behaviour.

[panic! (thomas-schend)]

Just to note:

This error occured with mimic. not verified if it also happens with luminous.

[Jonathan Rosser (jrosser)]

There is now much more explicit ceph version pinning in openstack-ansible so this issue should be fixed.