The first goal is to create a set of Docker containers properly packaged to run all processes related to the application.
If the application is already packaged as a Docker container by the original developers and is already available on Docker Hub, you can use that directly and skip this step.
While there are various different ways to create a container in Docker, within SLATE we recommended using a
Dockerfile. This allows a third party, such as the SLATE app curators, to easily follow and understand the contents of a Docker container. You can look at the container repositories on SLATE GitHub for examples and guidance.
Each SLATE application should reside in a separate git repository in the GitHub slateci group. The name of the repository should be containter-appname. The directory structure should look like
root: Contains Dockerfile (if the app is a single container), README, LICENSE. | --- app: Contains all the sources for the application. The main script should | be called entrypoint.sh where appropriate --- local-test: Contains the deployment for a local minikube | --- build: Contains build.sh to build the images and run.sh to start the app in minikube
As a base image, we recommend CentOS or Ubuntu.
Each application should include a README that documents how to use the container. In particular, it should include a table with all the ways in which the container can be configured in the following format:
|MY_PARAM||Conf param (ENV)||A parameter passed through an environment variable.||-e MY_PARAM=value|
|/etc/myapp/myapp.conf||Conf file (VOLUME)||A configuration file passed through volumes.||-v ~/myapp.conf:/etc/myapp/myapp.conf|
|/var/data/myapp||Data dir (VOLUME)||Persistent storage that must survive redeployment.||-v /storage/data/myapp:/var/data/myapp|
|/var/cache/myapp||Cache dir (VOLUME)||Storage space that is preferable to survive between redeployment but can be deleted.||-v /tmp/cache/myapp:/var/cache/squid|
|/var/scratch||Temp dir (VOLUME)||Temporary storage space that can be deleted when done.||-v /tmp/scratch:/var/scratch|
Each image should be published through Docker HUB. Make sure you have an account on DockerHub and you are a member of the slateci organization on DockerHub. On DockerHub, logged in as the organization, create a repository linked to the github repository. The name of the repository on DockerHub should match “slateci/appname” where appname matches the github repository “container-appname”. In case the github repository has more than one image, the DockerHub repository should match “slateci/appname-componentname”.