Tuesday, February 21, 2012

selenium under jenkins after a firefox update

A client ran into a problem recently. After an upgrade of firefox, they suddenly had many selenium test failures. I was confused and couldn't figure it out for a *long* time.

When we'd connect to the running test (vnc), there were two tabs in the controlling firefox window. It turns out that the second tab was a "Thank you for upgrading firefox". That would have been innocuous if it just sat there in the background. Unfortunately, selenium took it over and then started to run the test in *both* tabs.

Since some tests changed session state (e.g., login, do some logged in work, logout) tests would fail when one tab would log the user in and the other tab would log the user out while the first tab wasn't finished yet.

Running firefox manually while forcing it to use the base profile used by selenium fixed the issue. We could also just have edited prefs.js and modified the lastAppVersion entry, but the first fix is easier (it does the lastAppVersion modification) and anyway I only learned about modifying lastAppVersion directly after I'd already done the first fix :-).

Thursday, February 02, 2012

Binding host directories to container directories in lxc with lxc.mount.entry

I'm very happy about lxc.mount.entry in lxc containers (working in Ubuntu 11.10 Oneiric host, not tested on older hosts since I don't have any around).


lxc.mount.entry=/home/[user]/[some_directory] /var/lib/lxc/[container_name]/rootfs/home/[user]/[some_directory] none defaults,bind 0 0

That lets me mount a directory on the host (/var/lib/lxc/**/[some_directory]) inside the container somewhere (in this example,

I'd tried something like that with samba but had instability problems so gave up. Most of the time it would work fine, but sometimes (I never had the time or inclination to figure out why) something in samba would get out of sync and I'd not be able to write new files from the LXC container, delete files, etc.

Samba does have an advantage in that the UIDs don't have to be the same since you specify which user the files will be mounted by locally. But it's easy enough to synchronize UIDs between host and container.