========= Verwalter

:Status: Proof of Concept :Documentation: http://verwalter.readthedocs.org

Verwalter manages local configuration data and signals processes for reload. It's similar in spirit to confd_ or consul-template_ but has very different feature set.

Verwalter also has optional resource management facility and may provide service discovery too.

Features:

• Decentralized distribution of configuration
• Includes scriptable automated resource management (scripting via lua)
• Allows resource management even in minority partitions
• May provide discovery of only same-partition services in case of partitioning
• Liquid templates for configuration files
• Web interface to view current configuration state

Assumptions:

• Partitions happen
• Need some resource management in minority partition (even if it's essentially a "shutdown this service in minority partition", which can't be done if configuration is stored in zookeeper/consul/etcd)
• Need service discovery in minority partition, better if we could provide "only thease instances are available in current partition"

How it works:

• Collects metrics via cantal_
• Makes decisions in 10 second rounds
• Takes into account from 0.5 to 60 minutes of historical metrics
• Checks reachable nodes at each round
• Uses raft-like algorithm with weaker consistency guarantees

.. _cantal: http://cantal.readthedocs.org .. _confd: https://github.com/kelseyhightower/confd .. _consul-template: https://github.com/hashicorp/consul-template