The most strikingly different characteristic of Docker, when compared to other deployment platforms, is the single responsibility per container Design (although some see it differently). One reason this looks so different is that many application developers view the complete software stack on which they deploy as a collection of components on a single logical server. For developers of larger applications, who already have experience deploying distributed stacks, the security and configuration complexity of Docker may feel more familiar. Docker brings a fresh approach to distributed stacks; one that may seem overly complex for developers of smaller applications to enjoy the convenience of Deploying their full stack to a single logical server. Link to create applications Docker does mitigate some of the complexity of a distributed stack by way of Linking. Linking is a way to connect multiple containers so that they have access to each other’s resources. Communication between linked containers happens over a private network between the two containers. Each container has a unique IP address on the private network. We’ll see later on that share volumes are a special case in Linking containers. Statelessness and Persistence One core concept behind Docker containers is that they are transient. They are fast and easy to start, stop and destroy. Once stopped, any resources associated with the running container are immediately returned to the system. This stateless approach can be a good fit for modern web applications, where statelessness simplifies scaling and concurrency. However, the question remains about what to do with truly persistent data, like records in a database. Docker answers this question of persistence with Volumes. At first glance this appears to only provide persistence between running containers, but it can be configured to share data between host and container that will survive after the container exits. It’s important … Continue reading A Review of Docker