[ANN] juju-core 1.9.1 has been released

[David Cheney]

juju-core 1.9.1
===============

A new experimental release of Juju, juju-core 1.9.1 is now available for 
testing. This is first release of the Go port of Juju and should be 
considered _experimental_.

Getting Juju
------------

juju-core 1.9.1 is available from the Gophers PPA

https://code.launchpad.net/~gophers/+archive/go

New and Notable
---------------

In addition to the port from Python to Go, this release includes several 
important improvements

* The Juju state is now implemented in MongoDB. This replaces ZooKeeper 
and provides the underlying foundation for making the state highly 
available.
* Experimental support for upgrading a Juju environment. This will allow 
Juju itself to be upgraded inside a running environment. See the juju 
upgrade-juju command.
* Internally all Juju agents incorporate the concept of a lifecycle. The 
lifecycle is a reliable way to manage the death and removal of resources 
in a predictable manner. For instance, the stop hook now works as expected.

Known bugs and limitations
--------------------------

As this is the first release of Juju in Go there are a large number of 
features which are still to be implemented. A non exhaustive list of 
known issues is as follows.

* juju-core 1.9.1 only supports EC2 as a provider. You may need to 
remove custom configuration items from your environments.yaml to produce 
a configuration file that juju-core 1.9.1 accepts.
* us-east-1 is the most reliable region to deploy into. Due to subtle 
differences in the EC2 regions, juju bootstrap may fail when creating 
the control bucket. This is issue #1042107, the current workaround is to 
use us-east-1.
* The juju-core package currently cannot be installed in parallel with 
juju 0.5/0.6 due to conflicting ownership of /usr/bin/juju (and others). 
This may be mitigated in the future with alternatives.
* destroy-service is not yet implemented. As a workaround you can remove 
all the units assigned to a service. This is issue #1027878.
* remove-unit currently does not cause the underlying instance to shut 
down. This somewhat reduces the usefulness of the previous workaround. 
#1067127
* Constraints are not yet implemented. #1027873
* Subordinate charms are not yet implemented.

We encourage everyone to subscribe the mailing list at 
juju-dev at lists.canonical.com, or join us on #juju-dev on freenode.

Dave Cheney
On behalf of the Juju team
https://launchpad.net/juju-core