Start rabbitmq-server a daemon with a custom RabbitMQ Node name

I just tried a different way to set RabbitMQ node name. RabbitMQ is setting node name properly if  NODENAME is in /etc/rabbitmq/rabbitmq-env.conf.  I am still not sure why RabbitMQ is ignoring RABBITMQ_NODENAME environment variable.

Now, I am struggling with a new issue.

My RabbitMQ Node is running on AWS EC2 RHEL7 and i executed the below commands to configure and run RabbitMQ-server as demon. 

RabbitMQ-Server is failed to start when ec2-instance reboots,  it logged “su: cannot open session: Permission denied” in /var/log/rabbitmq/startup_err.  

However i am able to start service manually after reboot using $ service rabbitmq-server start

$ yum install -y socat
$ rpm -Uvh rabbitmq.rpm –force –nodeps
$ chkconfig rabbitmq-server on
$ service rabbitmq-server start