Ubuntu 16.10 and Zeroconf

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I don’t do enough system admin to enjoy it when I do. (Does anyone?)

When you upgrade Ubuntu, you lose a lot of the software you’d installed. There’s a list of system admin tips that I try to remember here. (Which reminds me, I should find a better home for it for when Twitter dies.)

I couldn’t resolve names of Macs in my local network. I should point out what a shame it is that Mac addresses aren’t the same thing as MAC addresses, since Google as my primary system admin resource.

That’s the work of avahi-daemon and friends (a/k/a Zeroconf and Bonjour). For awhile I thought that something had broken there. But eventually, I figured out that was working, i.e., the problem lay elsewhere.

I wondered if they’d added a firewall to 16.10. They did (or, for all I know, they’ve always had one) called ufw (more here), but it’s (still) not enabled by default. If that ever changes, I can learn what to do about it here.

After about an hour, I found out there is something called nss-resolve. Which is actually a pretty clever idea. Except it wasn’t working. Its configuration file is well documented here. Good luck figuring that out.

Finally, I just compared my 16.10 /etc/nss-switch.conf file with the one from a working installation of 16.04.1. HAH!

Not only was there a difference, it gave me a string I could Google. That brought me to this: http://askubuntu.com/questions/837982/how-to-configure-local-dns-lookup-in-ubuntu-16-10

It also brought me to this: https://github.com/systemd/systemd/issues/4157, which (if I read it correctly) says that I should go ahead and use the string from 16.04.1 that works instead of the one from 16.10 that doesn’t.

Odds ‘n’ Ends

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MIT Tech Review: Your brain limits you to just five BFF’s. Dunbar’s number isn’t just one number.

There’s a Zinc flash at the moment of conception.

Phys.org: New State of Water Molecule Discovered. Quantum tunneling!!!

NPR: 40 Years On, the Genius of 2112.

ExJon: Shun the Crowd, Embrace the Remnant

Acton: Bruce Wayne, Capitalist Superhero:

What we have in Bruce Wayne, CEO, then, is an embodiment of noblesse oblige, the idea that nobility (an elevated position in society) comes with certain responsibilities. The concept has been tainted in the minds of some by its association with hereditary aristocracy and paternalism, but the essential idea is praiseworthy.

Just Odds (no Ends today)

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Luna thought that Ron might suffer from a variety of this problem.

Awe-inspiring: a type II-P supernova caught in mid-burst. The explosion takes months, then hours, then no time at all. (Kind of like Hemingway’s character’s bankruptcy.)

An MIT course in how to make your own videos to publish on YouTube. (Ignore the headline.)

Finally, a beautiful video of undisturbed places. Trust me.

Arctic Climate Change and Extinction

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I can barely understand the abstract:

The Arctic Ocean is undergoing rapid climatic changes including higher ocean temperatures, reduced sea ice, glacier and Greenland Ice Sheet melting, greater marine productivity, and altered carbon cycling. Until recently, the relationship between climate and Arctic biological systems was poorly known, but this has changed substantially as advances in paleoclimatology, micropaleontology, vertebrate paleontology, and molecular genetics show that Arctic ecosystem history reflects global and regional climatic changes over all timescales and climate states…. Climate-driven biological impacts included large changes in species diversity, primary productivity, species’ geographic range shifts into and out of the Arctic, community restructuring, and possible hybridization, but evidence is not sufficient to determine whether or when major episodes of extinction occurred.