rabbitmq-server fails to start after hostname has changed for first time

Question

Remove the old installation of RabbitMQ to fix this problem. Here are steps to reinstall RabbitMQ. These commands are run as the root user:

1. Stop RabbitMQ: rabbitmqctl stop

2. Change /etc/hosts

3. Change /etc/hostname

4. Uninstall old RabbitMQ: dpkg -P rabbitmq-server

5. Remove RabbitMQ’s database: rm -rf /var/lib/rabbitmq

6. Find erlang’s process that is running rabbit: ps ax | grep rabbit

7. Kill the listed process

8. Reinstall RabbitMQ: apt-get install rabbitmq-server

I wrote about these steps on my blog.

REVISION

I moved my blog to a new website.

Thanks to Richard H Fung.

His steps helped me to solve this issue.

But I did not have to re-install the rabbitmq.

When I opened my /etc/hosts file I found that IP assigned to my hostname is different than the actual ip(192.168.1.200 [static]).

#/etc/hosts  
127.0.0.1       localhost  
192.168.1.115   HOSTNAME

so I just changed IP address to 192.168.1.200 in my /etc/hosts file and it worked fine.

Richard's answer is good, but you might lose some information in the rabbitmq queues. The following is a possible way to preserve the previous setup of rabbitmq with the new host name.

A Short Answer:

If you want to keep the new host name change, then you can create a rabbitmq-env.conf files in /etc/rabbitmq that references the old host name and all should be good. The following is what should be in the rabbitmq-env.conf file:

NODENAME=rabbit@OLDHOSTNAME

After adding the config file, restart the rabbitmq server then you should be good. (e.g. service rabbitmq-server restart (might need a sudo with ubuntu))

For more details you can read from the rabbitmq website: https://www.rabbitmq.com/man/rabbitmq-env.conf.5.man.html

More Details About the Answer:

I had a similar hostname issues using CentOS... The root issue was when rabbit installs, it references the current host name at the time of install. Since this is a rabbitmq thing, the solution should work for other linux flavors. If you want to see the full answer, you can see it at: rabbtimqadmin - Could not connect: [Errno -2] Name or service not known

You could solve this problem by either deleting the erlang mnesia database associated with rabbitmq or reinstalling rabbitmq.

I got hint for first solution from rabbitmq mailing list. Excerpt from answer, The Erlang Mnesia database is host specific (because it is a distributed DB). The simplest way to get you fixed is to clear out the database dir.

The second method is the easiest way (not recommend though). To uninstall do

dpkg -P rabbitmq-server

You can refer this link if you would like to know more about installing/removing debian packages.

On Windows, the issue I was facing was due to the McAfee firewall. The exact error was:

epmd error for host "<HOSTNAME>": address (cannot connect to host/port)

It started working as soon as I disabled the firewall