Joe Black | me@joeblack.nyc | github
This project was created in order to override calls to gethostname(2) and sethostname(2) in libc. This is mainly useful inside docker containers for situations where you cannot control the conditions in which the container was originally started in a similarly useful way, such as under Kubernetes.
Some applications, especially erlang applications, impose requirements related to the erlang distribution protocol that make running them under containers, especially Kubernetes, a painful experience. This is the usecase overridehostname was designed for. Although this can also be achieved by running the container with the SYS_ADMIN capability, I felt that is a rather unacceptable compromise just to change a container hostname.
- Place liboverridehostname.so.1 somewhere easy to remember. I use
/usr/local/lib/personally. - Add the entire path to the library to LD_PRELOAD and export. Example:
export LD_PRELOAD=/usr/local/lib/liboverridehostname.so.1this alone does not activate the library.
- Export
OVERRIDE_HOSTNAME=trueto your environment. Example:export OVERRIDE_HOSTNAME=true.
hostname <new-hostname>- To add the hostname and FQDN to /etc/hosts
echo "<ip.add.re.ss> <new-hostname-fqdn> <new-hostname>" >> /etc/hosts- To remove the old hostname if you aren't using it anymore
sed -i "/$OLD_HOSTNAME/d" /etc/hostsUnder docker this is harder, but the following hack will work
echo "$(sed "/$OLD_HOSTNAME/d" /etc/hosts)" > /etc/hosts