docker-discover-tasks

Distributed discovery of docker service tasks

Design

• Exposes the GET <hostname>:<port>/register API to allow a host to register their hostname and IP address in /etc/hosts. register also returns the hostname of the host running the API
• On start up, queries <service-name>.<task-id> to retrieve a list of all the IP addresses of the tasks. Uses the register API to register the local hostname and local IP address with the remote host. The returned remote hostname is registered in the local /etc/hosts file.
• The result is that all tasks (hosts) have an eventually consistent /etc/hosts file that points to all other tasks. Moreover, if a task dies and is restarted, the restarted task will eventually update all the other tasks with the latest IP address.
• All API requests are fault-tolerant and will retry if the service is not yet available
• All writes and reads to /etc/hosts are synchronized