Example: add systemd-nspawn machine, install packages, add user

systemd-nspawn-add-machine.sh

#!/bin/bash
# Add systemd-nspawn machine, install base packages, create builder user

set -eu

if [ $# -ne 1 ]; then
  echo "usage: $0 MACHINE"
  exit 1
fi

MACHINE=$1

if [ -d "/var/lib/machines/$MACHINE" ]; then
  echo "machine '$MACHINE' already exists"
  exit 2
fi

BUILDER_GID=1000
BUILDER_UID=1000

echo "--> install packages"
yum -y --releasever=7 --installroot=/var/lib/machines/$MACHINE install \
  systemd systemd-networkd passwd yum vim-enhanced bash bash-completion \
  less psmisc iputils iproute net-tools mc vim sudo wget curl redhat-lsb-core \
  epel-release rpmdevtools make yum-utils '@Development Tools'

echo "--> configure container"
systemd-nspawn --machine=$MACHINE -- /bin/bash << EOF
rm -f /etc/securetty
echo export TERM=screen > /etc/profile.d/profile.sh
echo export LANG=en_US.utf-8 >> /etc/profile.d/profile.sh
EOF

echo "--> configure users"
systemd-nspawn --machine=$MACHINE -- /bin/bash << EOF
echo "root:root" | chpasswd
groupadd -g $BUILDER_GID builder
useradd -u $BUILDER_UID -g builder -G wheel builder
echo "builder:builder" | chpasswd
sudo -u builder mkdir -p /home/builder/{bin,tmp}
sudo -u builder rpmdev-setuptree
EOF

echo "--> add systemd-nspawn@$MACHINE.service.d/override.conf file"
mkdir -p /etc/systemd/system/systemd-nspawn@$MACHINE.service.d
cat << EOF > /etc/systemd/system/systemd-nspawn@$MACHINE.service.d/override.conf
[Service]
ExecStart=
ExecStart=/usr/bin/systemd-nspawn --keep-unit --boot --link-journal=try-guest --machine=%I \\
  --bind=/storage/%I/rpmbuild:/home/builder/rpmbuild \\
  --bind=/storage/%I/bin:/home/builder/bin
EOF
systemctl daemon-reload

echo "--> create shared directories"
install -d -g $BUILDER_GID -m 0775 /storage/$MACHINE
install -d -g $BUILDER_GID -m 0775 /storage/$MACHINE/{rpmbuild,bin}

echo "--> start 'systemd-nspawn@$MACHINE' container"
systemctl start systemd-nspawn@$MACHINE