- Asynchronously, about 60 seconds after boot, a systemd timer fires which runs "/etc/update-motd.d/50-motd-news --force"
- It sources 3 admin-editable config variables in /etc/default/motd-news. The defaults are: ENABLED=1, URLS="https://motd.ubuntu.com", WAIT="5"
- The admin can disable it entirely (ENABLED=0), change or add other MOTD news sources (your corporate IT team could run its own), and change the wait time in seconds
- If it's enabled, that systemd timer job will loop over each of the URLS (note, that it's important that these should be https with valid SSL certificates), trim them to 80 characters per line, and a maximum of 10 lines, and concatenate them to a cache file in /var/cache/motd-news
- Every ~12 hours thereafter (with a little bit of random timer fuzzing), this systemd timer job will re-run and update the /var/cache/motd-news
- Upon login, the contents of /var/cache/motd-news is just printed to screen. There was a bug (fixed now, working its way through the Ubuntu update process), in that an empty cache file was not getting, if the fetch failed, so the fetch was retried every time (and failed every time, with the $WAIT delay of 5 seconds). Obviously, it was a simple fix.
As I am generally responsible for this feature in Ubuntu (as the Ubuntu Product Manager for the design, and the Ubuntu Core Developer for the implementation) I'll also respond to the discussion about this feature being included in Ubuntu at all...
- Back in 2009, Ubuntu was the first distribution to add the concept of a "dynamic MOTD", by introducing the /etc/update-motd.d/* structure of scripts. I originally implemented it for Landscape (a commercial package management system by Canonical), but it has since also been adopted by Debian, Amazon Linux, and others.
- It's a flexible framework that enables distro packages or administrators to add executable scripts in /etc/update-motd.d/* to generate informative, interesting messages displayed at login.
- This was quite interesting, in that for almost 40 years of Linux/UNIX, the "Message of the Day" was anything but that... It was a message that was created at one point in time, when the distro released, and that's about it. And we managed to change that.
- If you look in your Ubuntu's /etc/update-motd.d/, you'll see a set of scripts. One prints the generic "welcome" banner. The next one prints 3 links, as to where to find help. You'll also find one that counts and displays the number of package updates available for the local system. Another tells you if a reboot is required.
- All of these are locally generated, based on local information available on the system.
- In Ubuntu 17.04, we added /etc/update-motd.d/50-motd-news. This is the script who's design is described above. The motivation is threefold:
* Sometimes, there's critical information that either we, the distro, or perhaps even the local IT administrator of a fleet of systems needs to communicate to users at login. Think, "ShellShock", "Heartbleed", "StackClash". This seems to happen every few months, in the current state of the world.
* Other times, we need to communicate something about the distribution. EoL messages, new feature availability, etc.
* And sometimes, it's just a matter of presenting a fun fact. News from the world of Ubuntu. Or even your own IT department. Such was the case with the Silicon Valley / HBO message. It was just an interesting tidbit of potpourri from the world of Ubuntu. Last week's message actually announced an Ubuntu conference in Latin America. The week before, we linked to an article asking for feedback on Kubuntu. Before that, we announced the availability of Extended Security Maintenance updates for 12.04. And so on.
- There is a team of engineering managers at Canonical (the ~ubuntu-motd team in Launchpad), all of who have shared write access to the source code repository (lp:ubuntu-motd in Launchpad). Going forward, we're going to review one another's proposed message merges. In fact, that's an open source repository. You're welcome to propose your own messages for merging, if you have a well formatted, informative message for Ubuntu users. We'll be happy to review and include them in the future.
As always, I'm impressed with the critical analysis of the HackerNews community. We, the Ubuntu ecosystem, are held by the HN community to a very high standard, and we're quite humbled by that. Thank you for the continued feedback and response.
- Why did you copy/paste this on the bug tracker (https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/17...) and find/replace 'Ubuntu Community' with 'HackerNews community'? Doesn't that seem a little bit patronising to both parties
- Why didn't you actually address the issue? You said a lot of words but at no point did you say whether or not you would be removing this "feature" OR keeping it.