AKA: The Joy of juju run
Package upgrades across an OpenStack cloud do not always happen at the same time. In most cases they may happen within an hour or so across your cloud but for a variety reasons, some upgrades may be applied inconsistently, delayed or blocked on some servers.
As these packages may be rolling out a much needed patch or perhaps carrying a bug, you may wish to know which services are impacted in fairly short order.
If your OpenStack cloud is running Ubuntu and
managed by Juju and MAAS, here's
where juju run can come to the rescue.
For example, perhaps there's an update to the Corosync library libcpg4 and you wish to know which of your HA clusters have what version installed.
From your Juju controller, create a list of servers managed by Juju:
Juju 1.x:
$ juju stat --format tabular > jsft.out
Now you could fashion a query like this, utilising juju run:
$ for i in $(egrep -o '[a-z]+-hacluster/[0-9]+' jsft.out | cut -d/ -f1 | sort -u);
do juju run --timeout 30s --service $i "dpkg-query -W -f='\${Version}' libcpg4" | \
python -c 'import yaml,sys;print("\n".join(["{} == {}".format(y["Stdout"], y["UnitId"]) for y in yaml.safe_load(sys.stdin)]))';
done
The output returned will look something like this:
2.3.3-1ubuntu4 == ceilometer-hacluster/1
2.3.3-1ubuntu4 == ceilometer-hacluster/0
2.3.3-1ubuntu4 == ceilometer-hacluster/2
2.3.3-1ubuntu4 == cinder-hacluster/0
2.3.3-1ubuntu4 == cinder-hacluster/1
2.3.3-1ubuntu4 == cinder-hacluster/2
2.3.3-1ubuntu4 == glance-hacluster/3
2.3.3-1ubuntu4 == glance-hacluster/4
2.3.3-1ubuntu4 == glance-hacluster/5
2.3.3-1ubuntu4 == keystone-hacluster/1
2.3.3-1ubuntu4 == keystone-hacluster/0
2.3.3-1ubuntu4 == keystone-hacluster/2
2.3.3-1ubuntu4 == mysql-hacluster/1
2.3.3-1ubuntu4 == mysql-hacluster/2
2.3.3-1ubuntu4 == mysql-hacluster/0
2.3.3-1ubuntu4 == ncc-hacluster/1
2.3.3-1ubuntu4 == ncc-hacluster/0
2.3.3-1ubuntu4 == ncc-hacluster/2
2.3.3-1ubuntu4 == neutron-hacluster/2
2.3.3-1ubuntu4 == neutron-hacluster/1
2.3.3-1ubuntu4 == neutron-hacluster/0
2.3.3-1ubuntu4 == osd-hacluster/0
2.3.3-1ubuntu4 == osd-hacluster/1
2.3.3-1ubuntu4 == osd-hacluster/2
2.3.3-1ubuntu4 == swift-hacluster/1
2.3.3-1ubuntu4 == swift-hacluster/0
2.3.3-1ubuntu4 == swift-hacluster/2
Juju 2.x:
$ juju status > jsft.out
Now you could fashion a query like this:
$ for i in $(egrep -o 'hacluster-[a-z]+/[0-9]+' jsft.out | cut -d/ -f1 |sort -u);
do juju run --timeout 30s --application $i "dpkg-query -W -f='\${Version}' libcpg4" | \
python -c 'import yaml,sys;print("\n".join(["{} == {}".format(y["Stdout"], y["UnitId"]) for y in yaml.safe_load(sys.stdin)]))';
done
The output returned will look something like this:
2.3.5-3ubuntu2 == hacluster-ceilometer/1
2.3.5-3ubuntu2 == hacluster-ceilometer/0
2.3.5-3ubuntu2 == hacluster-ceilometer/2
2.3.5-3ubuntu2 == hacluster-cinder/1
2.3.5-3ubuntu2 == hacluster-cinder/0
2.3.5-3ubuntu2 == hacluster-cinder/2
2.3.5-3ubuntu2 == hacluster-glance/0
2.3.5-3ubuntu2 == hacluster-glance/1
2.3.5-3ubuntu2 == hacluster-glance/2
2.3.5-3ubuntu2 == hacluster-heat/0
2.3.5-3ubuntu2 == hacluster-heat/1
2.3.5-3ubuntu2 == hacluster-heat/2
2.3.5-3ubuntu2 == hacluster-horizon/0
2.3.5-3ubuntu2 == hacluster-horizon/1
2.3.5-3ubuntu2 == hacluster-horizon/2
2.3.5-3ubuntu2 == hacluster-keystone/0
2.3.5-3ubuntu2 == hacluster-keystone/1
2.3.5-3ubuntu2 == hacluster-keystone/2
2.3.5-3ubuntu2 == hacluster-mysql/0
2.3.5-3ubuntu2 == hacluster-mysql/1
2.3.5-3ubuntu2 == hacluster-mysql/2
2.3.5-3ubuntu2 == hacluster-neutron/0
2.3.5-3ubuntu2 == hacluster-neutron/2
2.3.5-3ubuntu2 == hacluster-neutron/1
2.3.5-3ubuntu2 == hacluster-nova/1
2.3.5-3ubuntu2 == hacluster-nova/2
2.3.5-3ubuntu2 == hacluster-nova/0
You can of course substitute libcpg4 in the above query for any package
that you need to check.
By far and away my most favourite feature of Juju at present, juju run
reminds me of knife ssh, which is unsurprisingly one of my favourite features
of Chef.