You have more control of what series you would like to deploy (controller only):
$ juju bootstrap --help | grep series
--bootstrap-series (= "")
Specify the series of the bootstrap machine
$ juju bootstrap --bootstrap-series=xenial
Select a cloud [localhost]: hit enter here for localhost as default choice
Enter a name for the Controller [localhost-localhost]: test1
Creating Juju controller "test1" on localhost/localhost
Looking for packaged Juju agent version 2.4.6 for amd64
To configure your system to better support LXD containers, please see: https://github.com/lxc/lxd/blob/master/doc/production-setup.md
Launching controller instance(s) on localhost/localhost...
- juju-324cd0-0 (arch=amd64)
Installing Juju agent on bootstrap instance
Fetching Juju GUI 2.14.0
Waiting for address
Attempting to connect to 10.102.181.77:22
Connected to 10.102.181.77
Running machine configuration script...
Bootstrap agent now started
Contacting Juju controller at 10.102.181.77 to verify accessibility...
Bootstrap complete, "test1" controller now available
Controller machines are in the "controller" model
Initial model "default" added
$ juju machines -m controller
Machine State DNS Inst id Series AZ Message
0 started 10.102.181.77 juju-324cd0-0 xenial Running
Above creates a controller with xenial. To create one with bionic run:
$ juju bootstrap --bootstrap-series=bionic
2) start conjure-up, select software to deploy and then you will be asked if you want to create new controller or use existing one. Select the controller created in step 1 and continue.
You could also bootstrap controller manually to lxd
and when it launches by default as you mentioned it would be bionic. Quick and easy.
Hope it will help.