How to install MJ12node (the Majestic-12 distributed crawler) on Ubuntu 17.10 / 18.04

A long time ago, I posted a guide to install MJ12node on Debian 7.

Since then, the process became a lot simpler because Linux got better, Mono got better and Majestic got better too. But still, I always have minor difficulties when trying to set up a new node, and apparently I’ve always forgotten to take notes and save them here… so far. Because it’s pretty trivial, I’ll just list the commands with very minimalist comments. They may need some adjustments for versions, but should remain quite stable, at least for a while:

Dependencies:

sudo apt-get install mono-runtime libmono-corlib4.5-cil libmono-sqlite4.0-cil

(that may seem small, but it will actually install a bunch of packages, for a total of about 40 MiB)

Get the latest node, unpack it and make it executable (for some reason, out-of-the-box it isn’t):

wget https://www.majestic12.co.uk/files/mj12node/mono/mj12node_linux_v1716_net45.tgz
tar xf mj12node_linux_v1716_net45.tgz
cd MJ12node
sudo chmod run.py 744

That’s it, you’re ready to start your node, use this command if you don’t want the web interface to be launched (it has no password and is on by default, hurray for security…)

./run.py -t

Note that in the console, you can at any time start and stop the web interface by pressing S for Start and T for sTop (but the point of running with -t is that it will remain off when the node auto-restarts, which is a setting I use and I recommend you to use, to avoid crashes)

Credits to myself lol, I actually found a forum post I made earlier while redacting this post, although I assume from the look of it that it was a summary of helping tips provided by other forum users 😉

On a side note, I also found another thread with instructions to run a more up-to-date Mono version. I guess you could do it if you really want to use cutting-edge Mono, but unlike a few years ago, the Mono version provided in recent Ubuntu distributions is stable enough. With MJ12node 1.7.16 and whatever Mono is the default in Ubuntu 17.10, and my node configured to restart every 12h, I’ve never had any crash that would cause my node to stop crawling forever, like I used to have before.