Category: Sysadmin

System administration is a special are of IT. It also has a special place in my heart. It is an interesting mixture of all the other disciplines, both common across the whole industry, and at the same time unique for each person, company, and geographical location. When I have something to say or share about system administration, I use this category.

Using the NetworkManager’s DNSMasq plugin

Fedora Magazine runs a handy article for anyone using work/corporate VPNs from a home computer – “Using the NetworkManager’s DNSMasq plugin“. This is also not the only use for the DNSMasq plugin. It comes in useful when you work local cluster setups for development or testing. Furthermore, pretty much any setup where you need to route DNS queries to different servers, this can either be used out of the box, or provide good ideas as to how to solve the problem.

Learn Enough Docker to be Useful

“Learn Enough Docker to be Useful” is a series of articles (so far 6) that explains different parts of Docker in a very simple and straightforward way. Here are the parts so far:

7 Awesome CloudFormation Hacks

Amazon CloudFormation templates are a bit tricky to write, regardless of whether you are working on your first one or you have been doing it for years. Sure, there are plenty of examples online, tools that make it easier (thanks Ansible!), and copy-pasting sections from your own library. But any tips on how to make the life easier are always welcome.

Hence, here’s a very handy collection of “7 Awesome CloudFormation Hacks“. These include:

  1. Combine two sequent intrinsic functions
  2. Use exported values from other stacks in !Sub
  3. Changes in cfn-init don’t trigger redeployment in AutoScaling Group
  4. Get Stack name of sibling stack in nested stacks
  5. AccountIds with leading zero
  6. Use Dictionaries as Stack Parameter
  7. DependsOn with condition

How To Build a Serverless CI/CD Pipeline On AWS

“How To Build a Serverless CI/CD Pipeline On AWS” is a nice guide to some of the newer Amazon AWS services, targeted at developers and DevOps. It shows how to tie together the following:

  • Amazon EC2 (server instances)
  • Docker (containers)
  • Amazon ECR (Elastic Container Registry)
  • Amazon S3 (storage)
  • Amazon IAM (Identity and Access Management)
  • Amazon CodeBuild (Continuous Integration)
  • Amazon CodePipeline (Continuous Delivery)
  • Amazon CloudWatch (monitoring)
  • Amazon CloudTail (logs)

The examples in the article are for setting up the CI/CD pipeline for .NET, but they are easily adoptable for other development stacks.

Introduction to Microservices, Docker, and Kubernetes

There is plenty of documentation, tutorials, and guides online, explaining Docker containers, Kubernetes container orchestration, and microservices. Here are a few that I found useful for the quick and simple introduction into these technologies and how to tie them together.

Firstly, some basic 101s:

Secondly, “Introduction to Microservices, Docker, and Kubernetes” YouTube video nicely puts all the things together, with complete code and configuration examples, some glue, and extra tips.

And finally, a few bits that you might need to solve on the way, which are not necessarily related, but can throw you off:

  • Some of the virtualization bits (such as VirtualBox) might fail to run properly if you have Secure Boot enabled. To solve this problem, reboot the machine, go to the BIOS, and disable Secure Boot (enable Legacy Mode).
  • Additionally, while you are there, check for the Virtualization Technology settings. Enable Virtualization Technology in the BIOS to further smooth out VirtualBox and friends.
  • While working on your first minikube cluster (sorting out VirtualBox and such), it helps to completely remove and start again, after sorting out any issues that prevent Kubernetes to start (proxy timeouts, etc). A quick “minikube delete && minikube start” will save you some time on troubleshooting weird issues, than just “minikube start” after a failure.

Have fun!