I needed to run a quick test on a virgin Linux system.

Rather than spinning up a virtual machine, I just ran a single Docker command, and was up and running.

docker run -it --entrypoint "/bin/bash" ubuntu:latest

That's it. Really, it's that simple.

From the Docker docs:

An ENTRYPOINT allows you to configure a …

I was on my mobile, looking up a few recipes, I was amazed at the number of intrusive ads I was getting, which made reading the web pages almost impossible.

Decided it was time to investigate Pi-hole, as I'd heard good things about it.

The Pi-hole is a DNS sinkhole that protects your devices from unwanted content, …

The purpose was to have a Linux box act as a simple router.

Devices:

• Device1, configured with a 10.10.10.10 IP.
• Device2, which will be our router, configured with 2 interfaces: 10.10.10.1 and 192.168.1.245.
• Device3, which is my Internet-facing router, with an internal IP of 192.168.1.1

The router is going to be …

Horrible idea in a production box, but great idea for a single user lab system.

To accomplish this, we'll use the visudo command, which edits the /etc/sudoers file in a safe manner, aka, protect you from seriously messing up your system.

sudo visudo

At the bottom of that file, add (assuming your username is tom, …

By default Docker needs to be run as the root user.

Not practical or advisable in a production, or shared system to be consistently logged in as root (think running with scissors).

Out of the box, attempting to run Docker as a non-root user gets this error:

whoami
tom

docker run hello-world
docker: Got permission …

Doing some lab testing, and needed to add another interface on an Ubuntu server virtual machine.

Quickly added it via the host (TrueNAS), but it came unconfigured and uninitialized.

The interface is in a down state, so it doesn't show up in ifconfig without using a switch:

ifconfig
enp0s4: flags=4163< …