kentaro/serf-hosts の Shell Script 版。本家はこっちです → https://github.com/kentaro/serf-hosts

event_handler.sh

#!/bin/sh

hosts='/etc/hosts'
event=${SERF_EVENT}

read member
name=`echo ${member} | cut -d ' ' -f 1`
addr=`echo ${member} | cut -d ' ' -f 2`
role=`echo ${member} | cut -d ' ' -f 3`

if [ ! -w ${hosts} ]; then
    echo "Cannot write file: ${hosts}" 1>&2
    exit 1
fi

if [ ${event} = 'member-join' ]; then
    if ! grep ${name} ${hosts} > /dev/null; then
        echo -e "${addr}\t${name}" >> ${hosts}
    fi
elif [ ${event} = 'member-leave' ] || [ ${event} = 'member-failed' ]; then
    sed -i "/${name}/d" ${hosts}
fi