[rabbitmq-discuss] Cannot start cluster?

Sat Jan 15 11:41:47 GMT 2011

On 14/01/2011 7:38PM, Brian Parkinson wrote:
> Hello - starting to play with clustering - I am using Rabbit 2.2.0 on
> Mac.
>
> Running one server (either by 'rabbit-server' or 'rabbit-multi
> start_all 1') works fine. Trying to start a cluster with 2 nodes
> fails - see output below.
>
> 1. Any ideas?

Hi Brian. If I had to guess I would say this is because you've got the 
management plugin installed. rabbitmq-multi assigns sequential AMQP 
listening ports for the nodes it starts, but it doesn't know anything 
about the port opened by rabbitmq_mochiweb (or any other ports the nodes 
might be configured to open - SSL, STOMP etc).

I think you'll want to start the nodes without using rabbitmq-multi, 
just with multiple invocations of rabbitmq-server, using environment 
variables to configure each node differently. I use a script like:

start-node.sh:
~~~~
#!/bin/sh
RABBITMQ_NODE_PORT=$1 RABBITMQ_NODENAME=$2 \
RABBITMQ_MNESIA_DIR=/tmp/rabbitmq-$2-mnesia \
RABBITMQ_PLUGINS_EXPAND_DIR=/tmp/rabbitmq-$2-plugins-scratch \
RABBITMQ_LOG_BASE=/tmp \
RABBITMQ_SERVER_START_ARGS="-rabbit_mochiweb port 5$1" \
/path/to/rabbitmq-server
~~~~

and then invoke it as

start-node.sh 5672 rabbit
start-node.sh 5673 hare

etc. Note that this will start RabbitMQ in the foreground.

Note that neither rabbitmq-multi nor this approach will actually cluster 
the nodes; you'll need something like:

rabbitmqctl stop_app
rabbitmqctl reset
rabbitmqctl cluster rabbit at hostname hare at hostname
rabbitmqctl start_app

to form a cluster.

> 2. A quick question/confirmation about a cluster. Assume I have a
2-node cluster running, and my client app connects via a
ConnectionFactory pointing at host/port of node1. If node1 then goes
down, will my client app continue to talk to node2?

No, I'm afraid you need to handle reconnection yourself.

Cheers, Simon