Discovery Service

The discovery.etcd.io package is only usable during the initial bootstrap of the etcd cluster. We extended this package to support for dynamic maintenance of cluster membership while keeping it backward-compatible with the original package.

APIs

• GET /new?size=N : returns a clsuter ID for bootstrapping a cluster of size N
• GET /members/CLUSTER_TOKEN : returns a comma-separated list of latest members of the cluster.
• POST /renew: this API is called by a cluster manager periodically to update the etcd cluster's latest quorum members.
• GET /health : returns the health of the discovdery service. the output is OK or an error message.
• GET /CLUSTER_TOKEN/{machine} : this is used by etcd instances to form a quorum during the bootstrap process.

Configuration

The service has three configuration options, and can be configured with runtime arguments.

• --etcd-urls / DISC_ETCD_URLS: comma separated list of backend etcd cluster members. Default value is set to "http://127.0.0.1:2379"
• --addr / DISC_ADDR: address:port of the discovery service.

Docker Container

You may run the service in a docker container:

docker pull quantum/discovery
docker run -d -p 80:8087 -e DISC_ADDR=... -e DISC_ETCD_URLS=... quantum/discovery

Development

The discovery service uses gin for easy development. It is simple to get started:

install: go get github.com/codegangsta/gin

cd cmd
gin -appPort 8087
curl --verbose -X PUT localhost:3000/new

Discussion

• This implementation provides security by obscurity.