Cleaning up what is installed by Juju when bootstrapping or launching a container has been requested for by some users of Juju over time. With the changes to the bootstrap series supported by Juju in the up and coming release (2.7), it should be possible to audit what’s installed.
One that’s been pinpointed for removal is cloud-utils, originally used for caching images internally and to help support Precise as a series, it’s been superseded by the caching support of LXD client.
So going forth client-utils has been removed from bootstrapping in 2.7.
In terms of performance, I use an apt-cache to improve the speed of bootstrapping, but even with this change I saw a dramatic improvement of bootstrapping from 4m43s average to 3m2s average over 10 bootstraps locally on LXD.