CONSUL

Consul operation guide. Consul is used for service discovery. Leela discover the machines by reading that information from consul.

UPGRADE

First upgrade the servers, one by one. After that you may upgrade the clients, again, one at a time.

CLUSTER INFO

  • consul members # returns the cluster members and its status
  • curl http://localhost:8500/v1/status/peers # current raft peers [usually three];
  • curl http://localhost:8500/v1/status/leader # must return exactly one;

ADDING INSTANCES

  1. make sure the directory /etc/consul/conf.d and the file /etc/consul/config are properly configure. That file should come from CFengine.
  2. /etc/init.d/consul start

REMOVING INSTANCE

Since the consul monitors a machine and all its services, if you ever remove an instance you must also remove all of its services. Follow the procedure to stop and remove every service individually and then simply stops consul:

  1. /etc/init.d/consul stop

CONFIG FILES

  • /etc/consul/config

SERVICE FILES

If you ever change any of these files, issue consul reload to apply the changes.

  • /etc/consul/conf.d/*.service

BOOTSTRAPING A NEW CLUSTER

All machines have died, somehow! Then you need to put the cluster back on:

  1. env CONSUL_EXTRA_OPTS="-bootstrap" /etc/init.d/consul start

Wait this instance to get back online. It should be the sole instance thus the leader. Now you can put the rest online normally [the dns should be working too].

  1. /etc/init.d/consul start