package maas-rack-controller 2.1.3+bzr5573-0ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[rumseed]

:)

ProblemType: Package
DistroRelease: Ubuntu 17.04
Package: maas-rack-controller 2.1.3+bzr5573-0ubuntu1
ProcVersionSignature: Ubuntu 4.9.0-11.12-generic 4.9.0
Uname: Linux 4.9.0-11-generic x86_64
ApportVersion: 2.20.4-0ubuntu1
Architecture: amd64
Date: Thu Dec 22 18:47:31 2016
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2016-02-11 (315 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
PackageArchitecture: all
RelatedPackageVersions:
 dpkg 1.18.10ubuntu1
 apt 1.4~beta2
SourcePackage: maas
Title: package maas-rack-controller 2.1.3+bzr5573-0ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Christian Ehrhardt  (paelzer)]

Hi,
and thank you for your report.
The version is from zesty, I just installed the same package and it triggered as is.

From your log:
Setting up maas-rack-controller (2.1.3+bzr5573-0ubuntu1) ...
Traceback (most recent call last):
  File "/usr/sbin/maas-rack", line 85, in <module>
    main()
  File "/usr/sbin/maas-rack", line 81, in main
    run()
  File "/usr/sbin/maas-rack", line 52, in run
    from provisioningserver.__main__ import main
  File "/usr/lib/python3/dist-packages/provisioningserver/__main__.py", line 8, in <module>
    import provisioningserver.boot.install_grub
  File "/usr/lib/python3/dist-packages/provisioningserver/boot/__init__.py", line 387, in <module>
    PXEBootMethod(),
  File "/usr/lib/python3/dist-packages/provisioningserver/boot/__init__.py", line 275, in __init__
    assert issubclass(type(self.template_subdir), Optional[str])
  File "/usr/lib/python3.5/typing.py", line 770, in __subclasscheck__
    raise TypeError("Unions cannot be used with issubclass().")
TypeError: Unions cannot be used with issubclass().

@Maas Team - please take a look this actually should never have passed installability tests, but then it could have been some sort of side effect by another update.
To trigger you can just init a new lxd container and run "apt-get install maas-rack-controller"

[Brian Morton (rokclimb15)]

Ref https://bugs.launchpad.net/ubuntu/+source/python3.5/+bug/1650202 and https://github.com/python/typing/commit/7baf6fe2a6d96ab09c807aac174650baa35d15dd

Optional returns a Union, which can't be subclassed.