Getting something similar to this bug while trying to install openstack-base bundle on clean MAAS environment. 

JUJU version 1.24.6-trusty-amd64

status on this units report hook failed

    units:
      nova-cloud-controller/0:
        workload-status:
          current: error
          message: 'hook failed: "cloud-compute-relation-changed" for nova-compute:cloud-compute'
          since: 22 Oct 2015 15:54:39-06:00
        agent-status:
          current: idle
          since: 22 Oct 2015 15:54:39-06:00
          version: 1.24.7
        agent-state: error
        agent-state-info: 'hook failed: "cloud-compute-relation-changed" for nova-compute:cloud-compute'
        agent-version: 1.24.7
        machine: 3/lxc/1
        open-ports:
        - 3333/tcp
        - 8773/tcp
        - 8774/tcp
        - 9696/tcp
        public-address: 172.16.1.144

and logs full of this: 

2015-10-22 21:37:34 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:38 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:41 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:45 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:48 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:51 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:56 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:37:59 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:03 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:06 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:09 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:12 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:15 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:18 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:21 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:24 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")
2015-10-22 21:38:27 ERROR juju.worker runner.go:223 exited "rsyslog": x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "juju-generated CA for environment \"rsyslog\"")