$ juju bootstrap costack costack -v --to vm0 --debug
2016-06-22 19:52:44 INFO juju.cmd supercommand.go:60 running juju [2.0-beta9.4037 gc go1.6.1]
2016-06-22 19:52:44 DEBUG juju.cmd.juju.commands bootstrap.go:387 preparing controller with config: map[controller-uuid:8353157e-8d7a-4a7b-817f-b879ef5a5799 bootstrap-timeout:1800 type:maas name:controller uuid:8353157e-8d7a-4a7b-817f-b879ef5a5799]
2016-06-22 19:52:45 DEBUG juju.provider.maas environprovider.go:31 opening model "controller".
2016-06-22 19:52:45 DEBUG maas controller.go:80 read version failed: &errors.Err{message:"", cause:(*json.SyntaxError)(0xc82040a1a0), previous:(*errors.Err)(0xc8202b6c30), file:"github.com/juju/gomaasapi/controller.go", line:780}
2016-06-22 19:52:45 INFO cmd cmd.go:129 Creating Juju controller "costack" on costack
2016-06-22 19:52:45 INFO juju.cmd.juju.commands bootstrap.go:512 combined bootstrap constraints:
2016-06-22 19:52:45 INFO cmd cmd.go:129 Bootstrapping model "controller"
2016-06-22 19:52:45 DEBUG juju.environs.bootstrap bootstrap.go:157 model "controller" supports service/machine networks: true
2016-06-22 19:52:45 DEBUG juju.environs.bootstrap bootstrap.go:159 network management by juju enabled: true
2016-06-22 19:52:45 INFO juju.environs.bootstrap tools.go:98 looking for bootstrap tools: version=2.0-beta9.4037
2016-06-22 19:52:45 INFO juju.environs.tools tools.go:106 finding tools in stream "devel"
2016-06-22 19:52:45 INFO juju.environs.tools tools.go:108 reading tools with major.minor version 2.0
2016-06-22 19:52:45 INFO juju.environs.tools tools.go:116 filtering tools by version: 2.0-beta9.4037
2016-06-22 19:52:45 DEBUG juju.environs.tools urls.go:109 trying datasource "keystone catalog"
2016-06-22 19:52:46 DEBUG juju.environs.simplestreams simplestreams.go:680 using default candidate for content id "com.ubuntu.juju:devel:tools" are {20160220 mirrors:1.0 content-download streams/v1/cpc-mirrors.sjson []}
2016-06-22 19:52:50 DEBUG juju.environs.simplestreams simplestreams.go:458 index has no matching records
2016-06-22 19:52:50 INFO juju.provider.common destroy.go:22 destroying model "controller"
2016-06-22 19:52:50 INFO juju.provider.common destroy.go:33 destroying instances
2016-06-22 19:52:50 INFO juju.provider.common destroy.go:53 destroying storage
2016-06-22 19:52:50 ERROR cmd supercommand.go:448 failed to bootstrap model: Juju cannot bootstrap because no tools are available for your model.
You may want to use the 'agent-metadata-url' configuration setting to specify the tools location.
Download as text
So the real cause of the failed bootstrap was that the daily ppa was used without passing --upload-tools to bootstrap.
The message about not being able to read the version is what is output when checking if the MAAS is 1.9 or 2.0. It is harmless, but could be made into a nicer message.