devstack源码分析

# root Access
# -----------

# OpenStack is designed to be run as a non-root user; Horizon will fail to run
# as **root** since Apache will not serve content from **root** user).  If
# ``stack.sh`` is run as **root**, it automatically creates a **stack** user with
# sudo privileges and runs as that user.

if [[ $EUID -eq 0 ]]; then
ROOTSLEEP=${ROOTSLEEP:-10}
echo "You are running this script as root."
echo "In $ROOTSLEEP seconds, we will create a user '$STACK_USER' and run as that user"
sleep $ROOTSLEEP

# Give the non-root user the ability to run as **root** via ``sudo``
is_package_installed sudo || install_package sudo
if ! getent group $STACK_USER >/dev/null; then
echo "Creating a group called $STACK_USER"
groupadd $STACK_USER
fi
if ! getent passwd $STACK_USER >/dev/null; then
echo "Creating a user called $STACK_USER"
useradd -g $STACK_USER -s /bin/bash -d $DEST -m $STACK_USER
fi

echo "Giving stack user passwordless sudo privileges"
# UEC images ``/etc/sudoers`` does not have a ``#includedir``, add one
grep -q "^#includedir.*/etc/sudoers.d" /etc/sudoers ||
echo "#includedir /etc/sudoers.d" >> /etc/sudoers
( umask 226 && echo "$STACK_USER ALL=(ALL) NOPASSWD:ALL" \
> /etc/sudoers.d/50_stack_sh )

echo "Copying files to $STACK_USER user"
STACK_DIR="$DEST/${TOP_DIR##*/}"
cp -r -f -T "$TOP_DIR" "$STACK_DIR"
chown -R $STACK_USER "$STACK_DIR"
cd "$STACK_DIR"
if [[ "$SHELL_AFTER_RUN" != "no" ]]; then
exec sudo -u $STACK_USER  bash -l -c "set -e; bash stack.sh; bash"
else
exec sudo -u $STACK_USER bash -l -c "set -e; source stack.sh"
fi
exit 1
else
# We're not **root**, make sure ``sudo`` is available
is_package_installed sudo || die "Sudo is required.  Re-run stack.sh as root ONE TIME ONLY to set up sudo."

# UEC images ``/etc/sudoers`` does not have a ``#includedir``, add one
sudo grep -q "^#includedir.*/etc/sudoers.d" /etc/sudoers ||
echo "#includedir /etc/sudoers.d" | sudo tee -a /etc/sudoers

# Set up devstack sudoers
TEMPFILE=`mktemp`
echo "$STACK_USER ALL=(root) NOPASSWD:ALL" >$TEMPFILE
# Some binaries might be under /sbin or /usr/sbin, so make sure sudo will
# see them by forcing PATH
echo "Defaults:$STACK_USER secure_path=/sbin:/usr/sbin:/usr/bin:/bin:/usr/local/sbin:/usr/local/bin" >> $TEMPFILE
chmod 0440 $TEMPFILE
sudo chown root:root $TEMPFILE
sudo mv $TEMPFILE /etc/sudoers.d/50_stack_sh

# Remove old file
sudo rm -f /etc/sudoers.d/stack_sh_nova
fi