This article should be considered deprecated since it speaks about the old (standalone) Swarm. To get more up-to-date information about the new Swarm mode, please read the Docker Swarm Introduction (Tour Around Docker 1.12 Series) article or consider getting the The DevOps 2.1 Toolkit: Docker Swarm book.
This series is split into following articles.
- A Taste of What Is To Come
- Manually Deploying Services
- Blue-Green Deployment, Automation and Self-Healing Procedure
- Scaling Individual Services
Previous articles put a lot a focus on Continuous Delivery and Containers with Docker. In Continuous Integration, Delivery or Deployment with Jenkins, Docker and Ansible I explained how to continuously build, test and deploy micro services packaged into containers and do that across multiple servers, without downtime and with the ability to rollback. We used Ansible, Docker, Jenkins and few other tools to accomplish that goal.
Now it's time to extend what we did in previous articles and scale services across any number of servers. We'll treat all servers as one server farm and deploy containers not to predefined locations but to those that have the least number of containers running. Instead of thinking about each server as an individual place where we deploy, we'll treat all of them as one unit.