Nowadays it’s really simple to install Transmission on CentOS 7 or EL distro. First you need to install EPEL packages:

$ yum install epel-release
$ yum -y update

…or use the following command if you’re running Red Hat Enterprise Linux:

$ yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm -E '%{rhel}').noarch.rpm

Install Transmission:

$ yum install transmission-cli transmission-common transmission-daemon

Create storage directory:

$ mkdir /ebs-data/transmission/
$ chown -R transmission.transmission /ebs-data/transmission/

Start and stop the Transmission to auto generate configs:

$ systemctl start transmission-daemon.service
$ systemctl stop transmission-daemon.service

To edit the config, you MUST first stop the daemon, otherwise the config will be overwritten after you restart the daemon:

$ systemctl stop transmission-daemon.service
$ var /var/lib/transmission/.config/transmission-daemon/settings.json

Edit config:

"download-dir": "/ebs-data/transmission",
"incomplete-dir": "/ebs-data/transmission",
"rpc-authentication-required": true,
"rpc-enabled": true,
"rpc-password": "my_password",
"rpc-username": "my_user",
"rpc-whitelist": "0.0.0.0",
"rpc-whitelist-enabled": false,

Save and start daemon:

$ systemctl start transmission-daemon.service

Access via your browser:

$ open http://localhost:9091/transmission/web/