How do I assign a static hostname to an Amazon EC2 instance running RHEL 7 or CentOS 7?
"I changed the hostname of my Amazon Elastic Compute Cloud (Amazon EC2) instance. However, when I reboot or stop and then start the instance, the hostname changes back."
"I changed the hostname of my Amazon Elastic Compute Cloud (Amazon EC2) instance. However, when I reboot or stop and then start the instance, the hostname changes back.Short descriptionTo make a hostname persist when you reboot or stop and start your EC2 instance, add the hostname to the appropriate configuration files on the instance.Note: The following steps apply to RHEL 7 or CentOS 7. For instructions that apply to other distributions, see one of the following:Change the system hostnameHow do I assign a static hostname to an Amazon EC2 instance running RHEL 5 or 6, CentOS 5 or 6, or Amazon Linux?How do I assign a static hostname to an Amazon EC2 instance running SLES?How do I assign a static hostname to an Amazon EC2 instance running Ubuntu Linux?Resolution1.    Run the hostnamectl command  from the shell to update the hostname of your RHEL 7 or CentOS 7 Linux instance. Replace persistent-hostname with the name you want the instance to use:sudo hostnamectl set-hostname --static persistent-hostnameNote: Changing the hostname by using the hostnamectl command doesn't update the /etc/hosts file. However, if necessary, you can manually edit this file to add the new hostname.2.    Use the vi text editor to update the /etc/cloud/cloud.cfg file on your RHEL 7 or CentOS 7 Linux instance. For general information about using the vi editor, run the command info vi from the command shell:Note: For instances running RHEL 7.4 and above, skip this step.sudo vi /etc/cloud/cloud.cfg3.    Add the following string to the bottom of the /etc/cloud/cloud.cfg file to be sure that the new hostname is preserved between restarts and reboots:preserve_hostname: trueSave and exit the vi editor.4.    Run the reboot command to reboot the EC2 instance and associate the new hostname with the instance:sudo reboot5.    Run the Linux hostname command without any parameters to verify that the hostname change persisted:hostnameThe command returns the new hostname that you specified in step 1.Note: If you install any system updates that affect the /etc/hosts file, the hostname file, or the hostname utility, then you must run these steps again.Follow"