On RHEL server 7.8, with a root file system mounted as read-only using the process documented here: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/sect-using_the_mount_command-mounting
Enter the following commands:
1) mount -o remount,rw /
2) nmcli connection add type ethernet ifname $DEVICE con-name $CONNECTION_NAME
The second command fails. The documentation implies that the root file system is mounted with write permissions, but nmcli is not able to make changes to the system. But after performing the following:
1) Change /etc/default/grub, /etc/sysconfig/readonly-root, /etc/fstab to allow enable write permissions to root file system
3) nmcli connection add type ethernet ifname $DEVICE con-name $CONNECTION_NAME
nmcli command succeeds.
Is there a way to up the static ip on a read-only file system without rebooting?