[rabbitmq-discuss] Unnecessarily complex packaging (Fedora)

Fri Sep 28 13:54:17 BST 2012

On 28/09/12 13:30, Lionel Cons wrote:
> I've looked at the init script as part of rabbitmq-server-2.8.7-1.noarch.rpm
> and I find it unnecessarily complex.

It *is* complex. I *think* all the complexity is necessary.

<snip description of how it all works>

> Hence my questions:
>   - why using sometimes runuser and sometimes su to change user?

We originally always used su. However, su is considered to start a login 
session, which means that under some common PAM configurations the 
"rabbitmq" user was considered always logged in. This prevented users 
from shutting down desktops / laptops on which rabbitmq-server was 
installed.

So why not use runuser all the time? Well, we want to try to keep the 
distro-specific parts of the server package as minimal as possible - the 
init script is distro specific but the wrapper scripts are not.

So on Debian / Ubuntu we start the server with start-stop-daemon rather 
than runuser. In fact it's not obvious that runuser is right for RPMs 
either, see thread here: 
http://lists.rabbitmq.com/pipermail/rabbitmq-discuss/2012-September/022706.html. 
Maybe we should be using "daemon" instead, at least on RHEL/Fedora RPMs.

But if we use start-stop-daemon / daemon to start the server, we 
certainly shouldn't use the same thing to invoke rabbitmqctl. 
rabbitmqctl is not a daemon. And we use rabbitmqctl to stop the server.

>   - why changing user in two different places (init script and wrapper)?

We need to change user in the init script in order to do the 
distro-specific magic that marks the process as a daemon. We need to 
change user in the wrapper so that rabbitmqctl can work. We also (to 
some extent) want to support running the server by invoking 
/usr/sbin/rabbitmq-server, in case you only want to start it for 
development.

So it's certainly possible that this could be arranged differently. We 
could have a separate wrapper for rabbitmq-server and make that wrapper 
vary by distro. I don't think that would count as any simpler though.

Cheers, Simon

-- 
Simon MacMullen
RabbitMQ, VMware