I needed to edit /etc/hosts on my chromebook, turns out the root filesystem on Chrome OS is read only.
First make sure your machine is set to developer mode and then reboot to apply any pending updates.
Execute the following to remove the root FS verification:
# sudo /usr/share/vboot/bin/make_dev_ssd.sh --remove_rootfs_verification
The command will fail with a warning and tell you to run the same command with –partitions 4 flag at the end where 4 can be any number. Run the command again with the new flag.
Then set the following variable:
# sudo crossystem dev_boot_signed_only=0
Then remount your root FS with:
sudo mount -o remount,rw /