Shell script to prepare a fresh machine for management with Ansible

ansible-bootstrap

#!/bin/bash

# usage: boostrap mybox.example.com path/to/id_rsa.pub

# preconditions: fresh install of Debian with ssh installed/running
# effects:
#  - hostname is set
#  - `ansible` user created with disabled password and added to sudo/ssh groups
#  - specified public key added to user's authorized_keys
#  - sudoers updated to allow no password operations

HOSTNAME="$(echo "$1" | cut -d '.' -f 1)"
KEY=$(cat $2)

ssh root@$1 <<BOOTSTRAP

#
# Hostname

hostname "${HOSTNAME}"
echo "127.0.1.1 ${HOSTNAME} $1" >> /etc/hosts

#
# Ansible user

adduser --disabled-password --gecos "" ansible
usermod -a -G sudo ansible
usermod -a -G ssh ansible

#
# SSH key for ansible user

mkdir ~ansible/.ssh
echo "$KEY" > ~ansible/.ssh/authorized_keys
chown -R ansible:ansible ~ansible/.ssh
chmod 700 ~ansible/.ssh
chmod 600 ~ansible/.ssh/authorized_keys

#
# Update sudoers

cp /etc/sudoers sudoers.tmp
sed -i '/%sudo/c\%sudo ALL=(ALL:ALL) NOPASSWD: ALL' sudoers.tmp
visudo -c -f sudoers.tmp && mv sudoers.tmp /etc/sudoers

BOOTSTRAP