goodservers/docker-doctor repository overview

⁠Docker doctor - health checker container for achieving zero downtime when using one container for app

The docker container checker waits until the new container is fully prepared and then removes the old one. Basically it checks the docker event sent from staring container. If have set HEALTH_CHECKER environment property then waits until their health is ok and afterwards old container is stopped and removed.

⁠Example

You have some application defined in docker (see examples/nodejsapp). When your CI runs the deployment phase it starts the new container and removes old one. But it takes some time to boot up application to healthy state. And if you have only one container it causes downtime. So you can setup the checker which waits until the new container is fully prepared and then removes the old one.

⁠Setup on server

docker-compose up

or see the example of usage with nginx, nginx-proxy, letsencrypt as a server docker-gateway⁠

⁠Setup for example app examples/nodejsapp

docker-compose -f docker-compose.yml --project-name=$(date +%s) up --scale nodejs_app=1 -d

⁠Environment props

⁠Requirements

• Good VPS or dedicated server⁠
• Installed docker and docker-compose
• nginx-proxy⁠ as a gateway for your deployed containers - they are automatically proxied - so your service is balanced between two containers.