Scripts agents are an easy way to add to Foglight out of the box monitoring capabilities and can be easily used to send counters from a Docker host to Foglight:
Step 1 - Find the commands that get the data.
The internet is full of examples for using Docker ps and docker images to get a lot of good counters from a Docker server.
docker ps -aq $1 | wc -l # get the number of all containers
docker ps -q $1 | wc -l # get the number of running containers
docker ps -a | grep -v -F 'Exited (0)' | grep -c -F 'Exited (' # get the number of crashed containers
docker images -aq $1 | wc -l # get the number of all images (including intermediate images)
docker images -q $1 | wc -l # get the number of images
docker images --filter "dangling=true" -q --no-trunc $1 | wc -l # get the number of dangling images
Step 2 - Send the result of the commands to standard output in a script agent.
Step 3 - Upload the script to Foglight, deploy the cartridge and create an agent.
The result is docker metrics in Foglight that can be used like any other Foglight metric.