Normally this happens because the vesta path is not part of your servers exported PATH.
Try this:
export PATH=$PATH:/usr/local/vesta/bin/
If you want that this left after reboot, then run this:
echo 'PATH=$PATH:/usr/local/vesta/bin' >> /root/.bash_profileI was using “sudo su” command to log in as root. But it should be “sudo su -“, so load the shell.