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Created February 26, 2013 20:10
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Version of lxc-start-ephemeral from Ubuntu 12.10 that passes the -s/ --define arguments through to lxc-start
#!/bin/bash
# (C) Copyright Canonical 2011,2012
# What lxc container to clone
LXC_BASE=""
# $2 is a path to bind mount e.g. /tmp/foo.
LXC_BIND=""
UNION="overlayfs"
usage() {
echo "usage: lxc-start-ephemeral [-U uniontype] [-d|--daemon] [-h] [-b bdir] [-u user] [-S key] -o orig -- [COMMAND [ARGS...]]"
}
help() {
usage
echo
echo "Runs an ephemeral (one-off) container"
echo
echo "Options:"
echo "orig : name of the original container"
echo "bdir : directory to bind mount into container"
echo "user : the user to connect to the container as"
echo "key : the path to the SSH key to use to connect"
echo "define : override certain elements of the container's config"
echo "-d : run in the background"
echo "-U : type of union (aufs or overlayfs)"
echo " Default is overlayfs"
echo
echo "if a COMMAND is given, then the container will run only as long"
echo "as the command runs. If no COMMAND is given, this command will"
echo "wait until the container is shut down"
}
shortoptions='hb:o:u:S:dU:s:'
longoptions='help,orig:,bdir:,user:,ssh-key:,daemon,union:define:'
LXC_RUNNING=0
LXC_MOUNTED=0
DAEMON=0
PASSTHROUGH_ARGS=""
cleanup_dirs()
{
# echo "umounting ephemeral_bind_dir $EPHEMERAL_BIND_DIR" >&2
sudo umount $EPHEMERAL_BIND_DIR
# echo "umounting lxc_dir $LXC_DIR" >&2
sudo umount $LXC_DIR/rootfs
# echo "umounting overlay" >&2
sudo umount $OVERLAY_DIR
# remove all contents of the content dir
sudo rmdir $LXC_DIR/ephemeralbind
sudo rmdir $LXC_DIR/rootfs
sudo rm -f $LXC_DIR/*
# echo "rming lxc_dir $LXC_DIR" >&2
sudo rmdir $LXC_DIR
# echo "rming overlay dir $OVERLAY_DIR" >&2
sudo rmdir $OVERLAY_DIR
}
cleanup() {
if [ $LXC_RUNNING -eq 1 ]; then
sudo lxc-stop -n $LXC_NAME
fi
if [ $LXC_MOUNTED -eq 1 ]; then
cleanup_dirs
fi
exit 1
}
do_mount() {
lower=$1
upper=$2
target=$3
if [ $UNION = "aufs" ]; then
sudo mount -t aufs -o br=${upper}=rw:${lower}=ro,noplink none ${target}
else
sudo mount -t overlayfs -oupperdir=${upper},lowerdir=${lower} none ${target}
fi
}
trap cleanup SIGTERM SIGINT SIGQUIT
getopt=$(getopt -o $shortoptions --longoptions $longoptions -- "$@")
if [ $? != 0 ]; then
usage
exit 1;
fi
eval set -- "$getopt"
while true; do
case "$1" in
-h|--help)
help
exit 1
;;
-s|--define)
shift
PASSTHROUGH_ARGS="$PASSTHROUGH_ARGS -s $1"
shift
;;
-o|--orig)
shift
LXC_BASE=$1
shift
;;
-b|--bdir)
shift
LXC_BIND=$1
shift
;;
-u|--user)
shift
LXC_USER=$1
shift
;;
-S|--ssh-key)
shift
LXC_KEY="-i $1"
shift
;;
-d|--detach)
DAEMON=1
shift
;;
-U|--union)
shift
UNION=$1
shift
;;
--)
shift
break;;
*)
echo $1
usage
exit 1
;;
esac
done
echo $PASSTHROUGH_ARGS
COMMAND=$@
COMMAND_LENGTH=$#
LXC_USER=${LXC_USER:-`id -un`}
# validation
if [ -z $LXC_BASE ]; then
echo "original container must be specified"
usage
exit 1
fi
if [ ! -d /var/lib/lxc/$LXC_BASE ] ; then
echo "no such lxc container $LXC_BASE"
exit 1
fi
if [ "$UNION" != "overlayfs" -a "$UNION" != "aufs" ]; then
echo "Invalid option for union: choose overlayfs or aufs."
exit 1
fi
setup_container()
{
echo "Setting up ephemeral container..."
OVERLAY_DIR=`mktemp -d /tmp/lxc-lp-XXXXXXX`
sudo mount -t tmpfs none $OVERLAY_DIR
LXC_DIR=`sudo mktemp -d --tmpdir=/var/lib/lxc $LXC_BASE-temp-XXXXXXX`
sudo chmod 755 ${LXC_DIR}
LXC_NAME=`basename $LXC_DIR`
sudo mkdir ${LXC_DIR}/rootfs
do_mount "/var/lib/lxc/$LXC_BASE/rootfs" "${OVERLAY_DIR}" ${LXC_DIR}/rootfs
EPHEMERAL_BIND_DIR=$LXC_DIR/ephemeralbind
sudo mkdir $EPHEMERAL_BIND_DIR
sudo mount -t tmpfs none $EPHEMERAL_BIND_DIR
LXC_MOUNTED=1
{
d1=/var/lib/lxc/${LXC_BASE}
for f in ${d1}/*; do
if [ -f $f ]; then
sudo cp $f $LXC_DIR/
fi
done
}
# Update the ephemeral lxc's configuration to reflect the new container name.
# Check all the places known distros keep hostnames.
# FIXME: should we sanity check the hostname to make sure it contains no bad chars?
for file in $LXC_DIR/fstab $LXC_DIR/config \
$LXC_DIR/rootfs/etc/hostname \
$LXC_DIR/rootfs/etc/hosts \
$LXC_DIR/rootfs/etc/sysconfig/network \
$LXC_DIR/rootfs/etc/sysconfig/network-scripts/ifcfg-eth0
do
if test -f "$file"
then
sudo sed -i -e "s/$LXC_BASE/$LXC_NAME/" $file
fi
done
# Update the fstab to have all bind mounts be ephemeral.
sudo cp $LXC_DIR/fstab $LXC_DIR/fstab.old
while read line; do
# Pull out the second field of the current line of fstab info
path=`echo -n $line | awk '{print $2}'`
# If LXC_BIND is not set, or the mount destination of this line is not
# LXC_BIND...
if [ -z "$LXC_BIND" -o "`readlink -f $path`" != "`readlink -f $LXC_DIR/rootfs$LXC_BIND`" ];
then
# ...then we should write some form of this line.
# If this line is a bind...
if [ `echo -n $line | awk '{print $4}'` == "bind" ]; then
# ...we should rewrite it as an overlay.
source=`echo -n $line | awk '{print $1}'`
upperdir=$EPHEMERAL_BIND_DIR$source
sudo mkdir -p $upperdir
sudo chown `sudo stat -c '%U.%G' $source` $upperdir
if [ $UNION = "overlayfs" ]; then
echo "none $path overlayfs upperdir=$upperdir,lowerdir=$source 0 0";
else
echo "none $path aufs br=${upperdir}=rw:${lowerdir}=ro,noplink 0 0";
fi
else
# Otherwise, we can pass it through unchanged.
echo "$line";
fi
fi
done < $LXC_DIR/fstab.old | sudo tee $LXC_DIR/fstab >/dev/null
# If LXC_BIND is defined, add it to fstab.
if [ -n "$LXC_BIND" ]; then
sudo mkdir -p $LXC_DIR/rootfs$LXC_BIND
echo "$LXC_BIND $LXC_DIR/rootfs$LXC_BIND none bind 0 0" | sudo tee -a $LXC_DIR/fstab >/dev/null
fi
# update the ephemeral container's MAC address (lifted from lxc-clone)
c=$LXC_DIR/config
# change hwaddrs
sudo mv ${c} ${c}.old
(
while read line; do
if [ "${line:0:18}" = "lxc.network.hwaddr" ]; then
echo "lxc.network.hwaddr= 00:16:3e:$(openssl rand -hex 3| sed 's/\(..\)/\1:/g; s/.$//')"
else
echo "$line"
fi
done
) < ${c}.old | sudo tee ${c} >/dev/null
sudo rm -f ${c}.old
}
get_ip()
{
# Get init's PID
PID=$(sudo lxc-info -n $1 -p | awk '{print $2}')
[ "$PID" = "-1" ] && return 1
# Get some unique path
DST=$(sudo mktemp -u --tmpdir=/run/netns/)
NAME=$(basename $DST)
# Prepare the /run/netns entry for "ip netns"
sudo mkdir -p /run/netns
sudo ln -s /proc/$PID/ns/net $DST
# Grab all the public globally routed IPv4 and IPv6 addresses
(sudo ip netns exec $NAME ip -4 addr show scope global && \
sudo ip netns exec $NAME ip -6 addr show scope global) | grep inet | while read line; do
ip=$(echo $line | awk '{print $2}' | cut -d '/' -f1)
echo "$ip"
done
sudo rm $DST
}
start_container()
{
echo "Starting up the container..."
sudo lxc-start -n $LXC_NAME $PASSTHROUGH_ARGS -d
sudo lxc-wait -s RUNNING -n $LXC_NAME
LXC_RUNNING=1
if [ $COMMAND_LENGTH -gt 0 ]; then
# When lxc-attach support arrives in the kernel, we can switch to
# that.
# Meanwhile, we use get_ip to wait for container's network to be up
# and to obtain the ip address, then we can ssh to the lxc.
TRIES=60
FAILED=1
# Repeatedly try to connect over SSH until we either succeed
# or time out.
for i in $(seq 1 $TRIES); do
# We call get_ip inside the loop to ensure the correct ip
# is retrieved even in the case the DHCP ip assignment
# changes during the process.
IP_ADDRESS=$(get_ip $LXC_NAME)
if [ -z "$IP_ADDRESS" ]; then
sleep 1
continue
fi
# Iterate through all the addresses (if multiple)
for ip in $IP_ADDRESS; do
ssh -n -o StrictHostKeyChecking=no \
-o UserKnownHostsFile=/dev/null \
$LXC_KEY $LXC_USER@$IP_ADDRESS -- "$COMMAND"
SSH_RET=$?
if [ ! 255 -eq $SSH_RET ]; then
# If ssh returns 255 then its connection failed.
# Anything else is either success (status 0) or a
# failure from whatever we ran over the SSH connection.
# In those cases we want to stop looping, so we break
# here
return $SSH_RET
fi
done
sleep 1
done
echo "could not get IP address - aborting." >&2
return 255
else
sudo lxc-wait -n $LXC_NAME -s RUNNING
echo "$LXC_NAME is running"
echo "You connect with the command:"
echo " sudo lxc-console -n $LXC_NAME"
sudo lxc-wait -n $LXC_NAME -s STOPPED
fi
}
stop_container()
{
echo "Stopping lxc" >&2
sudo lxc-stop -n $LXC_NAME
sleep 2
LXC_RUNNING=0
cleanup_dirs
}
handle_container()
{
setup_container
start_container
RET=$?
stop_container
exit $RET
}
if [ $DAEMON -eq 1 ]; then
handle_container &
exit 0
fi
handle_container
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