Let’s say you have a couple of Docker containers that run your favorite applications. You’d like to deploy these to some random server on the interwebs, so you lock down your Ubuntu server using the default UFW firewall, launch your containers and start using your applications.

You run ufw status to make sure that everything’s locked down the way it should be. Good to go! Or?

Not necessarily. You may be exposing your Docker applications to the whole world without even knowing it. There’s a long-running issue on Github explaining why. Here’s the short version: Docker is manipulating the iptables rules behind the scenes, while UFW tells you everything’s fine. Luckily, the solution is simple. Add this snippet to the file /etc/docker/daemon.json and restart Docker:

For a Docker or DevOps expert, this is probably common knowledge. For many developers and hobby server maintainers, it’s probably not. Have this in mind when deploying Docker applications to a server that is accessible to the world.

Don’t expose your Docker ports

This is something I don’t do that often, and I always forget the correct syntax. Thus this post.

Let’s say you have a table images and a table users. Now you want to delete all rows in table images that are associated with rows in the table users that are marked as deleted.

First, I usually do a visual inspection of the rows that will be deleted:

SELECT i.* FROM images i LEFT JOIN users u ON i.user_id = u.id WHERE u.deleted = 1;

The rows returned by this query are the rows that will be deleted when you run the following query:

DELETE i FROM images i LEFT JOIN users u ON i.user_id = u.id WHERE u.deleted = 1;

They key part here is to specify which table you want to delete from. In this case it’s the table i, which is the images table.

Deleting rows with a LEFT JOIN in MySQL

Disabling the password needed for sudo for a specific user is very easy in Ubuntu. This method applies to Ubuntu 16.04, but probably also other versions of Ubuntu and maybe even other distros.

Note: If this is the first time you’re running this command, you’ll most likely be presented with a list of editors to choose from. Choose the one you’re most comfortable with.

Then enter the following line at the end of the file:

Make sure to replace user with the username of the user you want to allow using sudo without entering a password.

Disabling password for sudo in Ubuntu

The Royal Norwegian Air Force practices formation flying every year in December. This year, they were schedule to fly over Bodø at 11:22 on December 8th. I managed to capture them with my zoom lens just a couple minutes after their scheduled arrival.

It wasn't the greatest light for photographing moving aircrafts, but I managed to get a couple of photos that turned out somewhat okay.

RNoAF Christmas Star 2022

I relatively recently posted about moving my website to WordPress. This actually still holds true, but I’ve given the website a new look and made some changes to the deployment routines.

Now I have a solid development focused foundation based on Trellis.

My website is my playground. This is where I can freely play with any new technologies that I come across and just have some fun. It’s important to me that some of the things I do on the computer is just for fun, and not only work related – there’s quite a lot of that.

My previous WordPress setup was just a Digital Ocean droplet created using their One-Click WordPress installation. This works fine if you just want a website up and running where you can add a theme and your favorite plugins and start typing. But it gets a bit trickier when you want to have a local development version of the site on your computer and a production version, and even maybe a staging version, running live on the internet.

This is where Trellis comes into play. It’s a ready-to-use setup based on Bedrock and Ansible and lots of other good stuff that makes it really simple to get up and running with three different environments:

The workflow for setting up a new site once you have Trellis installed is something along the lines of:

Do some small adjustments to a couple of configuration files for the hosts (servers) and the various environments

Create a git repository of your project and push it to ie. Github

And voilà! Your site is now deployed to the staging server. Of course, you must have set up a server somewhere to use as a staging server. The same goes for the production environment.

In addition to this, I use the WP DB Migrate Pro plugin(s) so that I can easily migrate my database and media files from one environment to another.

Website changes – again

I'm Kim, a full-stack web developer and entrepreneur based in Bodø, Norway. Currently occupied with running my own company, being a father and raising a little standard poodle.

Full-stack web developer, business owner and tech geek.