centos 에서 /etc/hosts 자동 업데이트

CentOS 를 설치하면 /etc/hosts 에는 localhost 만 등록되어 있다.

DHCP로 IP를 받고 hostname 을 받은 경우, 자동으로 hosts 파일을 업데이트 할 수 있다.

#!/bin/sh

# for Ubuntu

# /etc/dhcp/dhclient-exit-hooks.d/sethostname

# for CentOS

# /etc/dhcp/dhclient.d/sethostname

# for debugging:

echo "sethostname BEGIN"

export

set -x

echo new_ip_address=$new_ip_address

echo new_host_name=$new_host_name

echo new_domain_name=$new_domain_name

oldhostname=$(hostname -s)

if [ $oldhostname != $new_host_name ]; then

    # Rename Host

    echo $new_host_name > /etc/hostname

    hostname -F /etc/hostname

fi

# Update /etc/hosts if needed

TMPHOSTS=/etc/hosts.dhcp.new

if ! grep "$new_ip_address $new_host_name.$new_domain_name $new_host_name" /etc/hosts; then

    # Remove the 127.0.1.1 put there by the debian installer

    grep -v '127\.0\.1\.1 ' < /etc/hosts > $TMPHOSTS

    # Add the our new ip address and name

    echo "$new_ip_address $new_host_name.$new_domain_name $new_host_name" >> $TMPHOSTS

    mv $TMPHOSTS /etc/hosts

fi

echo "sethostname END"