Overview

This interface layer handles the communication with Etcd via the etcd-proxy interface.

Usage

Requires

This interface layer will set the following states, as appropriate:

• {relation_name}.connected The relation is established, but Etcd may not yet have provided any connection or service information.

• {relation_name}.available Etcd has provided its cluster string information, and is ready to handle incoming connections. The provided information can be accessed via the following methods:

  • cluster_string()

For example, a common application for this is configuring an applications backend kv storage, like Docker.

@when('proxy.available')
def prepare_etcd_proxy(proxy):
    con_string = proxy.cluster_string()
    opts = {}
    opts['cluster_string'] = con_string
    render('proxy_systemd_template', '/etc/systemd/system/etcd-proxy.service', opts)

Provides

A charm providing this interface is providing the Etcd cluster management connection string. This is similar to what ETCD requires when peering, declared as:

etcd0=https://192.168.1.2:2380,etcd1=https://192.168.2.22:2380

This interface layer will set the following states, as appropriate:

• {relation_name}.connected One or more clients of any type have been related. The charm should call the following methods to provide the appropriate information to the clients:

  • {relation_name}.provide_cluster_string()

Example (with the assumption you have layer-etcd included):

@when('proxy.connected')
def send_cluster_details(proxy):
    etcd = EtcdHelper()
    proxy.provide_cluster_string(etcd.cluster_string())

Contact Information

Maintainer

• Charles Butler charles.butler@canonical.com

Etcd

• Etcd home page
• Etcd bug trackers
• Etcd Juju Charm