Comment 3 for bug 1255242

You mention that "1.16.3 deploys wordpress and mysql and verifies that they are up".
However, looking at the log I see:
369:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju.worker.upgrader upgrader.go:134 desired tool version: 1.17.0
370:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju.worker.machiner machiner.go:52 "machine-1" started
371:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju runner.go:262 worker: start "lxc-watcher"
372:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju runner.go:262 worker: start "deployer"
373:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju.worker.deployer deployer.go:106 checking unit "wordpress/0"
374:juju-test-release-hp-machine-1:2013-11-26 15:09:23 INFO juju.worker.deployer deployer.go:146 deploying unit "wordpress/0"

That would indicate that the agent already thinks it wants to run Juju 1.17.0 *before* it has gotten to the point of deploying anything. I don't actually see any steps where the tool is clearly 1.16.3 (we should add a log message on startup of what version the agent is running, though we do have that in the RPC log on machine-0):

388:juju-test-release-hp-machine-0:2013-11-26 15:09:23 DEBUG juju.state.apiserver apiserver.go:102 <- [4] machine-1 {"RequestId":7,"Type":"Upgrader","Request":"SetTools","Params":{"AgentTools":[{"Tag":"machine-1","Tools":{"Version":"1.17.0-precise-amd64"}}]}}

Where machine-1 is reporting to the API server that it is running 1.17.0.
And I'll note that it isn't until:

1107:juju-test-release-hp-machine-2:2013-11-26 15:09:38 INFO juju charm.go:61 worker/uniter/charm: downloading cs:precise/mysql-29 from https://region-a.geo-1.objects.hpcloudsvc.com/v1/17031369947864/juju-pavlova-snags--chiko-roll-meat-pie-pasty-sauce-2013-10-10/cs_3a_precise_2f_mysql-29

a full 800 messages and 16 seconds later that machine-2 actually starts downloading the Mysql charm.

so this doesn't seem to be "upgrading mysql fails" but "installing mysql using 1.17.0" fails.

Can you confirm?