Services Flashcards
What is a service?
In a distributed application, different pieces of the app are called “services.” For example, if you imagine a video sharing site, there will probably be a service for storing application data in a database, a service for video transcoding in the background after a user uploads something, a service for the front-end, and so on. A service really just means, “containers in production.” A service only runs one image, but it codifies the way that image runs – what ports it should use, how many replicas of the container should run so the service has the capacity it needs, and so on. Scaling a service changes the number of container instances running that piece of software, assigning more computing resources to the service in the process.
What is a docker-compose.yml file?
A docker-compose.yml file is a YAML file that defines how Docker containers should behave in production.
What are compose files used for?
This file can be used to scale, limit, and redeploy our app. Changes to the service can be applied in place, as it runs, using the same command that launched the service: docker stack deploy.
