The article that follows is an extract from the last chapter of The DevOps 2.2 Toolkit: Self-Sufficient Docker Clusters book. It provides a good summary into the processes and tools we explored in the quest to build a self-sufficient cluster that can (mostly) operate without humans.
We split the tasks that a self-sufficient system should perform into those related to services and those oriented towards infrastructure. Even though some of the tools are used in both groups, the division between the two allowed us to keep a clean separation between infrastructure and services running on top of it. Continue reading →
A self-sufficient system is a system capable of healing and adaptation. Healing means that the cluster will always be in the designed state. As an example, if a replica of a service goes down, the system needs to bring it back up again. Adaptation, on the other hand, is about modifications of the desired state so that the system can deal with changed conditions. A simple example would be increased traffic. When it happens, services need to be scaled up. When healing and adaptation are automated, we get self-healing and self-adaptation. Together, they both a self-sufficient system that can operate without human intervention.
How does a self-sufficient system look? What are its principal parts? Who are the actors? Continue reading →
The third installment in The DevOps Toolkit Series is public! Even though, while I’m writing this post, only 20% of The DevOps 2.2 Toolkit: Self-Healing Clusters is finished, I hope you’ll pick it up and send me your feedback. I need your help in setting the direction of the book. I need you to help me shape it into something great. I need you to help me make this book a community effort.
Jenkins is, by far, the most used CI/CD tool in the market. That comes as no surprise since it’s been around for a while, it has one of the biggest open source communities, it has enterprise version for those who need it, and it is straightforward to extend it to suit (almost) anyone’s needs.
Products that dominate the market for years tend to be stable and very feature rich. Jenkins is no exception. However, with age come some downsides as well. In the case of Jenkins, automation setup is one of the things that has a lot to be desired. If you need Jenkins to serve as an orchestrator of your automation and tasks, you’ll find it to be effortless to use. But, if you need to automate Jenkins itself, you’ll realize that it is not as smooth as you’d expect from modern tools. Never the less, Jenkins setup can be automated, and we’ll go through one possible solution. Continue reading →
Docker 1.13 introduced a set of features that allow us to centrally manage secrets and pass them only to services that need them. They provide a much-needed mechanism to provide information that should be hidden from anyone except designated services.
A secret (at least from Docker’s point of view) is a blog of data. A typical use case would be a certificate, SSH private keys, passwords, and so on. Secrets should stay secret meaning that they should not be stored unencrypted or transmitted over a network. Continue reading →
I am continuously getting questions about blue-green releases inside a Docker Swarm cluster. Viktor, in your The DevOps 2.0 Toolkit book you told us to use blue-green deployment. How do we do it with services running inside a Swarm cluster? My answer is usually something along the following lines. With the old Swarm, blue-green releases were easier than rolling updates (neither were supported out of the box). Now we got rolling updates. Use them! The reaction to that is often that we still want blue-green releases.
This post is my brainstorming on this subject. I did not write it as a result of some deep thinking. There is no great wisdom in it. I just wrote what was passing through my mind while I was trying to answer another one of the emails containing blue-green deployment questions. What follows might not make much sense. Don’t be harsh on me. Continue reading →