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#!/bin/bash
#
# Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
# Date: 2011-01-26
# License: GPL v3+
## expect to pull these values from the environment:
# VMNAME=snapper
# OWNER=jrollins
# RAM=512
# SMP=2 # optional, specify number of CPUs
# HDA..HDZ=/path/to/disk # optional
#
# The following optional arguments control disk i/o on a per disk basis.
# All the variables start with the disk they are referencing (e.g.
# HDA or HDB). They all require qemu 2.6 and all default to 0 (unlimited).
# If a variable is not set, it won't be included. The qemu defaults are listed
# below (0 means unlimited).
# HD[A-Z]_IOPS_TOTAL=0
# HD[A-Z]_IOPS_TOTAL_MAX=0
# HD[A-Z]_IOPS_TOTAL_MAX_LENGTH=1
# HD[A-Z]_IOPS_READ=0
# HD[A-Z]_IOPS_READ_MAX=0
# HD[A-Z]_IOPS_READ_MAX_LENGTH=1
# HD[A-Z]_IOPS_WRITE=0
# HD[A-Z]_IOPS_WRITE_MAX=0
# HD[A-Z]_IOPS_WRITE_MAX_LENGTH=1
# HD[A-Z]_IOPS_SIZE=0
# HD[A-Z]_BPS_TOTAL=0
# HD[A-Z]_BPS_TOTAL_MAX=0
# HD[A-Z]_BPS_TOTAL_MAX_LENGTH=1
# HD[A-Z]_BPS_READ=0
# HD[A-Z]_BPS_READ_MAX=0
# HD[A-Z]_BPS_READ_MAX_LENGTH=1
# HD[A-Z]_BPS_WRITE=0
# HD[A-Z]_BPS_WRITE_MAX=0
# HD[A-Z]_BPS_WRITE_MAX_LENGTH=1
set -e
if [ -z "$VMNAME" ] ; then
exit 1
fi
TAP="${TAP:-${VMNAME}0}"
# MAC address is derived from a hash of the host's name and the guest's name:
MAC="${MAC:-$(printf "02:%s" "$(printf "%s\0%s" "$(hostname)" "${VMNAME}" | sha256sum | sed 's/\(..\)/\1:/g' | cut -f1-5 -d:)" )}"
BRIDGE="${BRIDGE:-br0}"
###################
OWNERGROUP=$(groups "$OWNER" | cut -f1 -d\ )
OWNERHOME=$(getent passwd "$OWNER" | cut -f6 -d: )
kvm_version=$(kvm --version | head -n1 | sed -E 's/^QEMU emulator version ([0-9.]+).*/\1/')
screen_version=$(screen --version | head -n1 | sed -E 's/^Screen version ([0-9.]+).*/\1/')
# Disks can be HDA, HDB, HDC, etc. For each disk, we want to detect the
# corresponding environment variables for disk read/write restrictions
# (e.g. HDA_IOPS_TOTAL, BPS_READ, etc). This function builds the variable
# disk_io_params each time it is run.
build_disk_io_params() {
local disk="$1"
local option variable argument value
disk_io_params=
if dpkg --compare-versions "$kvm_version" lt 2.6.0; then
# Only supported in version 2.6.0 or above.
return
fi
# Consider the disk i/o options
for option in IOPS_TOTAL IOPS_TOTAL_MAX IOPS_TOTAL_MAX_LENGTH IOPS_READ \
IOPS_READ_MAX IOPS_READ_MAX_LENGTH IOPS_WRITE IOPS_WRITE_MAX \
IOPS_WRITE_MAX_LENGTH IOPS_SIZE BPS_TOTAL BPS_TOTAL_MAX BPS_TOTAL_MAX_LENGTH \
BPS_READ BPS_READ_MAX BPS_READ_MAX_LENGTH BPS_WRITE BPS_WRITE_MAX \
BPS_WRITE_MAX_LENGTH; do
variable="${disk}_${option}"
if [ -n "${!variable}" ]; then
value=${!variable}
# Convert our environment variable into the syntax qemu expects
# (lower case with with a dash instead of underscore).
argument=$(echo "$option" | sed "s/_/-/g" | tr "[:upper:]" "[:lower:]")
# The variable will be appended to an existing series of options
# for the disk, so we want it to start with a comma.
disk_io_params="${disk_io_params},throttling.${argument}=${value}"
fi
done
}
up() {
# bring up the network tap:
modprobe -v tun
ip tuntap add dev "$TAP" mode tap user "$OWNER"
ip link set "$TAP" up
brctl addif "$BRIDGE" "$TAP"
chpst -u "$OWNER:$OWNERGROUP" mkdir -p "$OWNERHOME/vms/$VMNAME"
CDISO="$OWNERHOME/vms/$VMNAME/cd.iso"
NETBOOT="$OWNERHOME/vms/$VMNAME/netboot"
DEBIAN_INSTALLER="$OWNERHOME/vms/$VMNAME/debian-installer"
KERNEL="$OWNERHOME/vms/$VMNAME/kernel"
INITRD="$OWNERHOME/vms/$VMNAME/initrd"
KVMARGS=
unset KERNEL_CMDLINE
BOOTCHOICE=c
if [ -e "$KERNEL" -a -e "$INITRD" ] ; then
KVMARGS="-kernel $KERNEL -initrd $INITRD"
if [ "$CMDLINE" ]; then
KERNEL_CMDLINE="$CMDLINE"
fi
elif [ -e "$DEBIAN_INSTALLER" ] ; then
# FIXME: this should be generalized to pick the version and
# the architecture -- perhaps an empty $DEBIAN_INSTALLER would
# default to the latest sensible version, but its contents
# could otherwise select the version (and the arch if
# specified)
KVMARGS="-kernel /usr/lib/debian-installer/images/9/amd64/text/debian-installer/amd64/linux -initrd /usr/lib/debian-installer/images/9/amd64/text/debian-installer/amd64/initrd.gz -no-reboot"
KERNEL_CMDLINE="console=ttyS0,115200n8 -- console=ttyS0,115200n8"
# debian-installer should always be a one-shot, so that it reboots into
# normal mode:
rm -f "$DEBIAN_INSTALLER"
elif [ -e "$NETBOOT" ] ; then
BOOTCHOICE=n
elif [ -e "$CDISO" ] && [ -e $(readlink -f "$CDISO") ] ; then
KVMARGS="-cdrom $CDISO"
BOOTCHOICE=d
fi
for disk in HD{A..Z}; do
if printf "%s" "${!disk}" | grep '^/dev/mapper/'; then
mappername=$(printf "%s" "${!disk}" | sed 's!^/dev/mapper/!!')
udevadm trigger --subsystem-match=block --attr-match=dm/name="$mappername"
fi
done
udevadm trigger --sysname-match=kvm
# older versions need to have at least the first disk marked as boot=on or they cannot boot.
if kvm --version 2>/dev/null | sed 's/.*version \([0-9.]*\).*/\1/' | grep -q '^0' ; then
first_disk_extra_args=",boot=on"
else
first_disk_extra_args=
fi
index=0
# set up the disks, if needed:
if [ -n "$HDA" ]; then
build_disk_io_params HDA
driver=${HDA_DRIVER:-virtio}
KVMARGS="$KVMARGS -drive file=$HDA,if=$driver,cache=none,index=$index,format=raw${first_disk_extra_args}${disk_io_params}"
fi
# loop here on everything after HDA:
for disk in HD{B..Z}; do
index=$(( $index + 1 ))
if [ -b "${!disk}" ]; then
driver=virtio
driver_var_name="${disk}_DRIVER"
[ -n "${!driver_var_name}" ] && driver=${!driver_var_name}
build_disk_io_params "${disk}"
KVMARGS="$KVMARGS -drive file=${!disk},if=$driver,cache=none,index=$index,format=raw${disk_io_params}"
fi
done
if [ -e /usr/share/qemu/sgabios.bin ]; then
KVMARGS="$KVMARGS -device sga"
fi
LOGNAME="$OWNERHOME/vms/$VMNAME/console"
ln -sfT "$LOGNAME" ./servicelog
if [ -e "$LOGNAME" ] ; then
chpst -u "$OWNER" mv "$LOGNAME" "$LOGNAME".$(date +%F_%T%z|tr : .)
fi
MONITORNAME="$OWNERHOME/vms/$VMNAME/monitor.socket"
CONSOLENAME="$OWNERHOME/vms/$VMNAME/console.socket"
kvmsend() {
socat STDIO "UNIX:$MONITORNAME" <<EOF
$1
EOF
}
chpst -u "$OWNER:$OWNERGROUP:kvm" \
/usr/bin/kvm $KVMARGS \
-M "${MACHINE:-pc}" \
${KERNEL_CMDLINE:+-append "$KERNEL_CMDLINE"} \
-enable-kvm \
-nodefaults \
-nographic \
-name "$VMNAME" \
-m "$RAM" \
-boot order="$BOOTCHOICE" \
-chardev "socket,id=monitor,path=$MONITORNAME,server,nowait" -mon chardev=monitor,mode=readline \
-rtc base=utc \
-usb \
-device virtio-balloon-pci,id=balloon0,bus=pci.0 \
-chardev "socket,id=serial0,path=$CONSOLENAME,server" -device isa-serial,chardev=serial0 \
-smp "${SMP:-1},maxcpus=${MAXCPUS:-8}" \
-device "virtio-net-pci,vlan=0,id=net0,mac=$MAC,bus=pci.0" \
-net "tap,ifname=$TAP,script=no,downscript=no,vlan=0,name=hostnet0" &
local screen_log_args=-L
if dpkg --compare-versions "$screen_version" ge 4.05; then
screen_log_args="-L ./servicelog"
fi
chpst -u "$OWNER:$OWNERGROUP" \
/usr/bin/screen -D -m $screen_log_args -c /etc/screenrc.kvm-manager -S "$VMNAME" -t "$VMNAME" socat STDIO,raw,echo=0 "UNIX:${CONSOLENAME},retry=30" &
set +e
# handle regular signals
trap 'kvmsend system_reset; wait %1' HUP
trap 'kvmsend system_powerdown; wait %1' TERM
trap 'kvmsend cont; wait %1' CONT
trap 'kill -s TERM %1' QUIT
# use SIGINT instead of SIGSTOP for freezing the guest because
# trapping SIGSTOP is undefined:
# http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_28
trap 'kvmsend stop; wait %1' INT
trap 'kill %1 ; kill %2' EXIT
wait %1
}
down() {
set +e
brctl delif "$BRIDGE" "$TAP"
ip link set "$TAP" down
ip tuntap del mode tap dev "$TAP"
set -e
# no need to lock up the block device as well, since the owner might
# prefer to manipulate the disk directly.
}
log() {
LOGDIR="$OWNERHOME/vms/$VMNAME/servicelog"
chpst -u "$OWNER" mkdir -p "$LOGDIR"
exec chpst -u "$OWNER" svlogd -tt "$LOGDIR"
}
case "$1" in
up|down|log)
"$1"
;;
*)
echo "Usage: $0 [up|down]" >&2
exit 1
;;
esac
|
