juju doesn't use maas' knowledge of system architecture when picking tools

[Jason Hobbs]

When using maas as a provider, juju doesn't use maas' knowledge of the system architecture to pick the correct tools version.

For example, when bootstrapping with a constraint results in an armhf system being picked, amd64 tools are picked:
ubuntu@juju-dev:~$ juju bootstrap -v -v --constraints "tags=calxeda-highbank"
Launching instance
WARNING picked arbitrary tools &{"1.18.0-trusty-amd64" "https://streams.canonical.com/juju/tools/releases/juju-1.18.0-trusty-amd64.tgz" "a48fbeea9bd69ef4510994cff5f260c98c11d36fb48df4c9010e07970d951f71" %!q(int64=7419939)}

If I supply an additional constraint of "arch=armhf", the correct tools version is picked:

ubuntu@juju-dev:~$ juju bootstrap -v -v --constraints "tags=calxeda-highbank arch=armhf"
Launching instance
WARNING picked arbitrary tools &{"1.18.0-trusty-armhf" "https://streams.canonical.com/juju/tools/releases/juju-1.18.0-trusty-armhf.tgz" "ad0cd5731fda4c97c698a17d66d892f8de55c061542d09682c32c192e5a9ccee" %!q(int64=7085643)}

But, maas knows this system is armhf and therefore I shouldn't need to supply that myself as an additional constraint. This will result in non amd64 architectures not working unless special care is taken.

This affects 1.18.0-trusty-amd64.

[Andrew Wilkins (axwalk)]

I'm making some related changes, so will fix this while I'm there.

[Andrew Wilkins (axwalk)]

Fixed by https://github.com/juju/juju/pull/536