When Docker first came out it was a real mind bender of an experience for me. I simply couldn’t wrap my head around what a Docker image was, how it was different from a virtual machine and so on. “Why not just install the software from rpm?” I said.

I also struggled with how the app in the container was running inside of something and didn’t have access to anything. At the time I saw this just as a silly hurdle that made it more difficult than it should be to get something running rather than a core benefit of using containers.

Over time I got to know Docker and containers better. I gained an understanding of now images are created, how they could be given restricted resources, easily shared and so on. I started creating my own containers to further understand the process, got to know multi stage builds and so in.

Although I had gained a better understanding of the container itself I still couldn’t find a good use case for containers in my line of work. I was too used to creating VMs that ran a static set of services that rarely changed. Docker containers still seemed like another packaging format that has few additional advantages. It wasn’t until I started playing with container orchestration that things really started to click.

With container orchestration, and in particular Kubernetes, the power and convenience of containers becomes much harder to ignore. Orchestration was definitely the missing piece of the puzzle for me that sealed the deal. This is because orchestration solves a number common issues with running larger software infrastructure. One of the biggest issues that Kubernetes solves is how to swap out the running application with little fuss. By simply declaring that a running workload should update the Docker image in use Kubernetes will go through the process of starting the new container, waiting for it to be ready, adding it to the load balancer and then draining connections from the old container. While it’s true you can achieve all of that with a traditional setup it requires a lot more effort. This feature alone is what sold me on using Kubernetes at all and from there my current state of container acceptance.

With Kubernetes revealing the huge potential of containers I’ve since come back to exploring them for other uses outside of orchestration. Now, core features of containers that once bothered me are seen as advantages. I still see containers as a packaging format but one that works equally well on macOS and Windows as well as it does on Linux or in Kubernetes. As an “expert” I can provide a container to a user that has everything installed for some to tool. Previously this may have required me to write extensive documentation detailing the requirements, installation process and finally the configuration of whatever software it took to meet the user’s needs. A process that may end up failing or not work at all because the end user is using a different operating system or because of some other environment specific reason. With containers, if it works for me there is a much greater chance it will work for someone else as well.

Today I find myself building more and more containers for use in CI/CD pipelines. I see them as little utilities that I can chain together to create a larger solution. Similar to the Unix philosophy, I am creating containers that do one thing and do it well. These small containers are easy to maintain, easy to document and easy to use. And this, I believe, is one of the core strengths of containers. They encapsulate a solution into something that is easier to understand. Even though a container is technically more bloated because it contains not only the application itself but also all of its requirements, the end result is something that is ultimately easier to understand. Like writing code, you can write the most incredible for loop ever devised but if the next person can’t understand it is it still a good solution?

Throughout my career I’ve always enjoyed trying out new things to see how I can apply them to everyday problems or how they can be used to create great new opportunities. Docker was one the first things that I really struggled to understand and initially I thought “this is it, this is the tech my kids will understand that I won’t.” Today, however, I can see what a game changer containers are. When properly constructed containers are easier to understand, easier to share with others and easier to document. These are powerful reasons too use containers. There are new hurdles to overcome, like how to maintain them for security, but all things have tradeoffs and it’s up to us to decide which ones are worth it.

For some time I’ve been meaning to publicly release the custom component I’ve been using to show which if my Xbox friends are online and what they are playing. There was one issue I had with my component that kept me from releasing it however, it requires access to an API endpoint I would prefer to not offer to an unknown number of people and I’m not interested in scaling it up to sell.

What I decided to do instead is allow the service to be self hosted in the form of some add-ons for hass.io that the custom component can then talk to. The service is broken out into three parts. A part to manage an auth token, a part to basically proxy Xbox Live API requests and a part that glues to two together so the auth token can be shared. The original design was meant to scale well and easily and this is basically just a 1:1 port of the setup. 

The add-ons can be installed by adding this custom add-on URL to your add-on store on your hass.io instance – https://github.com/hassio-xbox/add-ons. Add the URL, refresh and then install the services in the following order

  • Redis Server
  • Xbox Live Credentials Manager (and then configure your username/password)
  • Xbox Live API Service

Once all services are up and running you can configure the component which is installed automatically. The component needs to be given the IP address of your hass.io instance as well as a list of gamertags to keep track of. The format looks like this:

sensor:
- platform: xru
ip: <hass.io instance ip>
gamertags:
- RealAngryMonkey
- Qwik

Once configured restart Home Assistant and you’ll see the status of your friends in the form of individual sensors for each. You can then group them to create a nice panel in your groups.yml file:

xbl_friends:
name: Xbox Live Friends
view: no
entities:
- sensor.realangrymonkey
- sensor.qwik

The end result looks like this:

MariaDB log output showing encryption is working

Utilizing encryption at rest to protect the database data living on your hard drive is a smart choice, especially when dealing with sensitive customer data. Encryption at rest protects the data files by encrypting the actual files the MySQL/MariaDB server reads and writes to on the file system. Although they are binary files they can still be read relatively easily using standard tools as well as being “imported” into a different MySQL/MariaDB server. Encryption at rest is just one part of a total solution and this post is going to cover what it takes to get it running using the AWS Key Management System for key control on macOS using Homebrew.

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There are times when it is necessary or desirable to access servers through a single host, called a bastion. This is the first host you'd access prior to using ssh to access some other host. Limiting access to the other hosts would either be controlled by firewall rules or simply because they don't have public IPs. Whatever your reason, a bastion host is a great way to increase security by decreasing the number of exposed hosts on the internet.

For the best security, all hosts should be configured to allow only key based authentication. This immediately negates any brute force based attempts to access your server. While convenient, it isn't necessary for you to use the same keys on all servers you access. Search the web for the best way to achieve key only authentication on your distribution of choice.

Configuring access to any server using a bastion host starts by first defining how you will connect to the bastion host itself. To get started, simply add an entry into your .ssh/config file that describes how to access the bastion host itself. As an example, lets say you have a bastion host at IP 192.168.0.1 and you've installed your public key to user called 'bastionuser'. Your entry would look like this:

HostName bastionhost
User bastionuser
Host 192.168.0.1

This entry does two things. It gives you a very easy way to ssh to your bastion host and it gives you a target you can use as a proxy to access other hosts. To use the entry you can simply issue 'ssh bastionhost' and you'll access your bastion host as user bastionuser using your default private key.

With access to the bastion host itself out of the way, you're now ready to create .ssh/config entries to access other servers that are only accessible through the bastion host. For this example, lets say a server with IP 192.168.1.2 is available from the bastion host. You'd create an entry that looks like this:

HostName targetserver
User targetuser
Host 192.168.1.2
ProxyCommand ssh bastionhost -W %h:%p

That's it! When you want to ssh to the target server, simply issue ssh targetserver and your connection will first hit the bastion host to be used as a proxy. Note that, at all times, your local private key will be used to make the connection unless you explicitly tell ssh to use something else using IdentityFile <path to file>. Even if you use different keys, those keys must always exist on your local system, keys on remote systems will never be used. It's up to you to find a way to distribute your keys to all other target servers.

In addition to using a bastion host for to access a single server or a set of them, you can also chain multiple bastion hosts together simply by configuring more entries with ProxyCommand. For example, lets say a server at 192.168.2.2 is only accessible from targetserver. You'd create an entry like this:

HostName finaldestination
User finaluser
Host 192.168.2.2
ProxyCommand ssh targetserver -W %h:%p

With this entry in place it is now possible to access your final destination by issuing ssh finaldestination. This configuration will instruct ssh to attempt to access finaldestination using target server, but in order to access targetserver to first go through the bastion host. There is technically no limit to the number of hosts you can proxy through but you'll eventually hit the limits of latency.

Whatever your reason for placing an NGINX proxy in front of your Gitlab installation, you need to ensure you’re using the right configuration to support all of Gitlab’s features. I recently discovered that although my installation was mostly working I couldn’t get pipeline/build logs properly. I discovered that my proxy configuration was to blame. After some searching around I finally found that my config wasn’t quite right. To get the most out of Gitlab and ensure a smooth experience use configuration shown below as a template for your own. In my setup I use LetsEncrypt for SSL so if you’re not you can remove any of the SSL specific parts. The important configuration information is contained the the location block.

 

upstream gitlab {
  server <ip of your gitlab server>:<port>;
}

server {
    listen          443;
    server_name     <your gitlab server hostname;

    ssl on;
    ssl_certificate <path to cert>;
    ssl_certificate_key <path to key>;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_prefer_server_ciphers on;
    server_tokens off;


    gzip on;
    gzip_vary on;
    gzip_disable "msie6";
    gzip_types application/json;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;

    location / {
       client_max_body_size   0;
       proxy_set_header    Host                $http_host;
       proxy_set_header    X-Real-IP           $remote_addr;
       proxy_set_header    X-Forwarded-Ssl     on;
       proxy_set_header    X-Forwarded-For     $proxy_add_x_forwarded_for;
       proxy_set_header    X-Forwarded-Proto   $scheme;

      proxy_pass https://gitlab;
    }
}

This configuration will properly pass all requests through to your Gitlab server as well as allow CI/CD pipeline logs to pass through properly.

Recently I found myself needing to perform a downgrade of Home Assistant in Hassio which wasn’t immediately obvious. If you need to downgrade your Hassio install enable the ssh add-on (or the web based one) and enter the following command on the console:

curl -d '{"version": "0.57.1"}' http://hassio/homeassistant/update

The command will hang for bit while Hassio downloads the different versions and prepares to install it.

I was recently introduced to a superb piece of software called Proxmox. Proxmox is a virtualization environment not unlike VMware ESXi. Capable of running full KVM based virtual machines or lightweight LXC based guests, Proxmox has proven to be the perfect solution for a home lab setup. Installing Proxmox is no different than installing any other Linux distribution and with minimal effort can be clustered together to form a system capable of migrating a guest from one host to another. With the right hardware you can even perform live migrations. Although Proxmox supports and is capable a lot more than I need it satisfies my desire to have a more “enterprise” like way to virtualize hardware in my home.

Proxmox is free with support plans available. If I were to use it anywhere other than at home I’d definitely play for the support subscription as it allows you to get access to the proper update repositories as well as, obviously, support. Without the support subscription your Proxmox is basically part of a testing repo meaning you get faster access to updates but also updates that are less tested.

In the coming weeks I’ll detail a bit more how I’m using Proxmox, how to setup KVM or LXC based hosts and provision them using Ansible.

Sometimes when using Ansible there is the need to reboot a server and wait for it to return. This simple recipe will allow you to achieve that while also getting some nice feedback so you know what is going on. You can place these tasks into a role or just in your playbook:

- name: Store target host and user
  set_fact:
  target_host: "{{ ansible_host }}"
  target_user: "{{ ansible_user }}"
 
- name: Reboot the server
  shell: sleep 2 && shutdown -r now "Ansible package updates triggered"
  async: 1
  poll: 0
  ignore_errors: true
 
- name: Wait for server to shutdown
  local_action: shell ssh -o BatchMode=yes -o ConnectTimeout=2 -o StrictHostKeyChecking=no "{{ target_user }}@{{ target_host }}" true
  register: result
  until: result.rc != 0
  failed_when: result.rc == -1
  retries: 200
  delay: 1
 
- name: Wait for server to be ready
  local_action: shell ssh -o BatchMode=yes -o ConnectTimeout=2 -o StrictHostKeyChecking=no "{{ target_user }}@{{ target_host }}" true
  register: result
  until: result.rc == 0
  retries: 200
  delay: 3