Ubuntu's settings won't open after setting CPU to 'performance'

Recently I was doing some benchmarking on my Ubuntu 22.04 PC, and as part of that benchmarking, I tried setting the CPU performance profile to performance. In the old days, this was not an issue, but it seems that modern Ubuntu only 'knows' about balanced and power-saver. Apparently performance is forbidden these days!

$ powerprofilesctl list
* balanced:
    Driver:     placeholder

    Driver:     placeholder

The problem was, I had set the profile to performance:

$ powerprofilesctl set performance

But suddenly the 'Settings' GUI app would no longer open (at least not after I had opened it and clicked into the 'power' section). A reboot didn't work, and even reinstalling control center (sudo apt-get install --reinstall gnome-control-center) didn't help!

When I tried opening the settings GUI from the command line, I got the following critical error:

apt_key deprecated in Debian/Ubuntu - how to fix in Ansible

For many packages, like Elasticsearch, Docker, or Jenkins, you need to install a trusted GPG key on your system before you can install from the official package repository.

Traditionally, you'd run a command like:

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -

But if you do that in modern versions of Debian or Ubuntu, you get the following warning:

Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).

This way of adding apt keys still works for now (in mid-2022), but will stop working in the next major releases of Ubuntu and Debian (and derivatives). So it's better to stop the usage now. In Ansible, you would typically use the ansible.builtin.apt_key module, but even that module has the following deprecation warning:

Ansible playbook to upgrade Ubuntu/Debian servers and reboot if needed

I realized I've never posted this playbook to my blog... I needed to grab it for a project I'm working on, so I figured I'd post it here for future reference.

Basically, I need a playbook I can run whenever, that will ensure all packages are upgraded, then checks if a reboot is required, and if so, reboots the server. Afterwards, it removes any dependencies no longer required.

- hosts: all
  gather_facts: yes
  become: yes

    - name: Perform a dist-upgrade.
        upgrade: dist
        update_cache: yes

    - name: Check if a reboot is required.
        path: /var/run/reboot-required
        get_md5: no
      register: reboot_required_file

    - name: Reboot the server (if required).
      when: reboot_required_file.stat.exists == true

    - name: Remove dependencies that are no longer required.
        autoremove: yes

Setting up a Raspberry Pi with 2 Network Interfaces as a very simple router

I needed a very basic 'Internet sharing' router setup with one of my Raspberry Pis, and I thought I'd document the setup process here in case I need to do it again.

I should note that for more complex use cases, or where you really need to worry about security and performance, you should use something like OpenWRT, pfSense, or VyOS—or just buy a decent out-of-the-box router!

Seeed Studios Raspberry Pi Compute Module 4 Router Board

But I needed a super-simple router setup for some testing (seriously... look at the picture—the thing's about to fall off my desk!), and I had two network interfaces on a Raspberry Pi running the 64-bit build of Raspberry Pi OS. These instructions work on that OS, as well as Debian, Ubuntu, and derivative distros.

Debugging networking issues with multi-node Kubernetes on VirtualBox

Since this is the third time I've burned more than a few hours on this particular problem, I thought I'd finally write up a blog post. Hopefully I find this post in the future, the fourth time I run into the problem.

What problem is that? Well, when I build a new Kubernetes cluster with multiple nodes in VirtualBox (usually orchestrated with Vagrant and Ansible, using my geerlingguy.kubernetes role), I get everything running. kubectl works fine, all pods (including CoreDNS, Flannel or Calico, kube-apiserver, the scheduler) report Running, and everything in the cluster seems right. But there are lots of strange networking issues.

Sometimes internal DNS queries work. Most of the time not. I can't ping other pods by their IP address. Some of the debugging I do includes:

Fixing 'UNREACHABLE' SSH error when running Ansible playbooks against Ubuntu 18.04 or 16.04

Ubuntu 16.04 and 18.04 (and likely future versions) often don't have Python 2 installed by default. Sometimes Python 3 is installed, available at /usr/bin/python3, but for many minimal images I've used, there's no preinstalled Python at all.

Therefore, when you run Ansible playbooks against new VMs running Ubuntu, you might be greeted with the following error:

Installing PHP 7 and Composer on Windows 10, Using Ubuntu in WSL

Note: If you want to install and use PHP 7 and Composer within Windows 10 natively, I wrote a guide for that, too!

.embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Since Windows 10 introduced the Windows Subsystem for Linux (WSL), it has become far easier to work on Linux-centric software, like most PHP projects, within Windows.

To get the WSL, and in our case, Ubuntu, running in Windows 10, follow the directions in Microsoft's documentation: Install the Windows Subsystem for Linux on Windows 10, and download and launch the Ubuntu installer from the Windows Store.

Updating all your servers with Ansible

From time to time, there's a security patch or other update that's critical to apply ASAP to all your servers. If you use Ansible to automate infrastructure work, then updates are painless—even across dozens, hundreds, or thousands of instances! I've written about this a little bit in the past, in relation to protecting against the shellshock vulnerability, but that was specific to one package.

I have an inventory script that pulls together all the servers I manage for personal projects (including the server running this website), and organizes them by OS, so I can run commands like ansible [os] command. Then that enables me to run commands like:

Ansible playbook to upgrade all Ubuntu 12.04 LTS hosts to 14.04 (or 16.04, 18.04, 20.04, etc.)

Generally speaking, I'm against performing major OS upgrades on my Linux servers; there are often little things that get broken, or configurations gone awry, when you attempt an upgrade... and part of the point of automation (or striving towards a 12-factor app) is that you don't 'upgrade'—you destroy and rebuild with a newer version.

But, there are still cases where you have legacy servers running one little task that you haven't yet automated entirely, or that have data on them that is not yet stored in a way where you can tear down the server and build a new replacement. In these cases, assuming you've already done a canary upgrade on a similar but disposable server (to make sure there are no major gotchas), it may be the lesser of two evils to use something like Ubuntu's do-release-upgrade.