URSim Controller on Ubuntu 20.04. No libxmlrpc for i386 available

URCap Development
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I have been trying to get the URSim Controller working with Ubuntu 20.04 and have everything up and running with the exception of the controller. Through the forums it seems to come back to the failed dependy in the install files, which should be updated to:

Dependencies_32: Changelibxmlrpc-c++8 libxmlrpc-core-c3tolibxmlrpc-c++8v5`

This is fine for Ubuntu 18, but when going to Ubuntu 20, this has one specific problem. There is no libxmlrpc-c++8v5 for 32 bit architecture available.

However, according to the Ubuntu website:
[Ubuntu – Package Search Results – libxmlrpc]

  • bionic (18.04LTS) (libs): Lightweight RPC library based on XML and HTTP [C++ runtime libraries] [ universe ]
    1.33.14-8build1: amd64 arm64 armhf i386 ppc64el s390x
  • focal (20.04LTS) (libs): Lightweight RPC library based on XML and HTTP [C++ runtime libraries] [ universe ]
    1.33.14-8build2: amd64 arm64 armhf ppc64el s390x

You can see that going from 18.04 to 20.04 the 32bit architecture is dropped.

I have seen a few youtube videos showing the URSim up and running on Ubuntu 20. Is anyone able to help out on how to get around this problem?

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I too was curious so I did some testing. The short answer is Ubuntu 20.04 and up no longer support multiarch i386 and although you can i386 flavored libraries, some vendors, like the libxmlrpc people have just chosen to drop those builds all together.

You can however take an 18.04 image and do a dist upgrade to 20.04 and even further to 22.04, and maven will still compile a URcap and the simulator will run, but it will have some glitches. Not worth the effort imho. I tried it out using a working 18.04 vmware image.

Until UR releases a 64bit version, anything greater than 18.04 isn’t possible. Luckily 1804 comes in just under the wire for being able to run all the other modern tooling like Eclipse, Netbeans, VSCode, git, etc, so really nothing of value lost from not upgrading.

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A few extra notes here. The UR starter pack has a nice OVA vm but it’s Ubuntu 16.04. There are big difference between Ubuntu 1604 and 1804, namely the switch to systemd from initd.

Luckily, 1804 can support most moden tooling like updated Eclipse+WindowBuilder, VSCode, git, etc so we don’t have to deal with 2004+ and still be able to fully use the sim and dev environment. I have yet to find a software that doesn’t still (barely) support 1804.

So, until UR makes some modifications on their end to allow 2004+ x64 to work, here’s the surprisingly simple way to get the UR Starter Pack updated to 1804 and working.

  • Download the start pack and deploy the OVA to your hypervisor of choice
  • Log into it an open a terminal
  • Run these commands, and these commands ONLY
    #this will take you to 1804, a reboot will happen when its done, select Y for all things
    sudo do-release-upgrade
    #this will make runit work with the new systemd, a requirement for UrSim to function
    sudo apt install runit-systemd
    #this will let URSim be able to know when URCaps are running/stopped/etc
    sudo chown root:ur /usr/bin/sv

And that’s it.
I recommend taking a snapshot of your VM before you run apt upgrade, or install new tools. The runint-systemd is brittle and if damaged, there’s no way to reinstall it. This only works because the release upgrade doesn’t remove a few older needed packages