How do I assign a static hostname to an Amazon EC2 instance running RHEL 7 or CentOS 7?

Short description

To 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 hostname

How 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?

Resolution

1.    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-hostname

Note: 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.cfg

3.    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: true

Save and exit the vi editor.

4.    Run the reboot command to reboot the EC2 instance and associate the new hostname with the instance:

sudo reboot

5.    Run the Linux hostname command without any parameters to verify that the hostname change persisted:

hostname

The 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.

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