Some users may accidentally install one or the other, or even both LXD and LXC.
Here is how to figure out which is which.
In this here, I am running LXD, and I have installed LXD from the snap package (of LXD). It’s a popular choice, and here you can see on how many Linux distros you can get the the snap package of LXD. Quite versatile and is supported all over the place. You have the option of either the latest version (currently 3.10), the latest stable version (currently 3.0.3, the Chromebooks will get it soonish), the previous stable version (currently 2.0.11).
$ which lxc
/snap/bin/lxc
The LTS versions of Ubuntu currently come with a DEB package of LXD. Ubuntu 16.04 has LXD 2.0.11, Ubuntu 18.04 has LXD 3.0.3. The above command would say here /usr/bin/lxc.
What about LXC? Not the LXC Linux Containers kernel functionality but rather the implementation also named LXC, which is the precursor of LXD and also supported from this website?
Here we run the command to locate lxc-create, the equivalent to lxc launch. It’s not installed on my computer and it comes from a different package.
$ which lxc-create
$ lxc-create
Command 'lxc-create' not found, but can be installed with:
sudo apt install lxc-utils
The following page, https://linuxcontainers.org/lxc/introduction/ is for LXC (the older implementation of Linux Containers), and commands like lxc-create.
The one on the Chromebook is LXD, found at https://linuxcontainers.org/lxd/introduction/
If you have a Linux distribution, you can install LXD and get more familiar with it. The latest version of LXD is 3.10, which has more features than the version the Chromebooks. With snap packages, you can switch channel and install the exact same version from your Chromebook.
If, instead, you do not have Linux, then you can use virtualization to install a Linux distribution (I suggest Ubuntu 18.04) and then setup LXD in there.
I have written a few tutorials on LXD.
I don’t have a Chromebook, so I do not have a section on this. But there is a related post from when Crostini was first introduced.