feat(vm_image_util): Rework the qemu wrapper script to work for PXE

Now the script can be used with a disk image or a kernel/initrd.
Using a disk with the PXE kernel should work too but haven't tried it.

build_library/qemu_template.sh

@@ -4,15 +4,17 @@ SCRIPT_DIR="`dirname "$0"`"
 VM_NAME=
 VM_UUID=
 VM_IMAGE=
+VM_KERNEL=
+VM_INITRD=
 VM_MEMORY=
 VM_NCPUS="`grep -c ^processor /proc/cpuinfo`"
-IMAGE_PATH="${SCRIPT_DIR}/${VM_IMAGE}"
 SSH_PORT=2222
 SSH_KEYS=""
 USAGE="Usage: $0 [-a authorized_keys] [--] [qemu options...]
 Options:
     -a FILE     SSH public keys for login access. [~/.ssh/id_{dsa,rsa}.pub]
     -p PORT     The port on localhost to map to the VM's sshd. [2222]
+    -s          Safe settings: single simple cpu, ide disks.
     -h          this ;-)
 
 This script is a wrapper around qemu for starting CoreOS virtual machines.
@@ -26,12 +28,14 @@ Any arguments after -a and -p will be passed through to qemu, -- may be
 used as an explicit separator. See the qemu(1) man page for more details.
 "
 
+safe_args=0
 script_args=1
-while getopts ":a:p:vh" OPTION
+while getopts ":a:p:svh" OPTION
 do
     case $OPTION in
         a) SSH_KEYS="$OPTARG" ;;
         p) SSH_PORT="$OPTARG" ;;
+        s) safe_args=1 ;;
         v) set -x ;;
         h) echo "$USAGE"; exit ;;
         ?) break ;;
@@ -73,18 +77,35 @@ else
     done
 fi
 
+# Start assembling our default command line arguments
+if [ "${safe_args}" -eq 1 ]; then
+    disk_type="ide"
+else
+    disk_type="virtio"
+    # Emulate the host CPU closely in both features and cores.
+    set -- -cpu host -smp "${VM_NCPUS}" "$@"
+fi
+
+if [ -n "${VM_IMAGE}" ]; then
+    set -- -drive if=${disk_type},file="${SCRIPT_DIR}/${VM_IMAGE}" "$@"
+fi
+
+if [ -n "${VM_KERNEL}" ]; then
+    set -- -kernel "${SCRIPT_DIR}/${VM_KERNEL}" "$@"
+fi
+
+if [ -n "${VM_INITRD}" ]; then
+    set -- -initrd "${SCRIPT_DIR}/${VM_INITRD}" "$@"
+fi
+
 
 # Default to KVM, fall back on full emulation
-# Emulate the host CPU closely in both features and cores.
 # ${METADATA} will be mounted in CoreOS as /media/metadata
 qemu-system-x86_64 \
     -name "$VM_NAME" \
     -uuid "$VM_UUID" \
     -m ${VM_MEMORY} \
-    -cpu host \
-    -smp "${VM_NCPUS}" \
     -machine accel=kvm:tcg \
-    -drive index=0,if=virtio,media=disk,format=qcow2,file="${IMAGE_PATH}" \
     -net nic,vlan=0,model=virtio \
     -net user,vlan=0,hostfwd=tcp::"${SSH_PORT}"-:22 \
     -fsdev local,id=metadata,security_model=none,readonly,path="${METADATA}" \
@@ -96,4 +117,4 @@ RET=$?
 # Cleanup!
 rm -rf "${METADATA}"
 trap - EXIT
-exit $?
+exit ${RET}

build_library/vm_image_util.sh

@@ -329,16 +329,12 @@ write_vm_conf() {
     fi
 }
 
-_write_qemu_conf() {
-    local vm_mem="${1:-$(_get_vm_opt MEM)}"
-    local src_name=$(basename "$VM_SRC_IMG")
-    local dst_name=$(basename "$VM_DST_IMG")
-    local dst_dir=$(dirname "$VM_DST_IMG")
-    local script="${dst_dir}/$(_src_to_dst_name "${src_name}" ".sh")"
+_write_qemu_common() {
+    local script="$1"
+    local vm_mem="$(_get_vm_opt MEM)"
 
     sed -e "s%^VM_NAME=.*%VM_NAME='${VM_NAME}'%" \
         -e "s%^VM_UUID=.*%VM_UUID='${VM_UUID}'%" \
-        -e "s%^VM_IMAGE=.*%VM_IMAGE='${dst_name}'%" \
         -e "s%^VM_MEMORY=.*%VM_MEMORY='${vm_mem}'%" \
         "${BUILD_LIBRARY_DIR}/qemu_template.sh" > "${script}"
     checkbashisms --posix "${script}" || die
@@ -363,19 +359,31 @@ EOF
     VM_GENERATED_FILES+=( "${script}" "${VM_README}" )
 }
 
-_write_pxe_conf() {
+_write_qemu_conf() {
+    local script="$(_dst_dir)/$(_dst_name ".sh")"
     local dst_name=$(basename "$VM_DST_IMG")
+
+    _write_qemu_common "${script}"
+    sed -e "s%^VM_IMAGE=.*%VM_IMAGE='${dst_name}'%" -i "${script}"
+}
+
+_write_pxe_conf() {
+    local script="$(_dst_dir)/$(_dst_name ".sh")"
     local vmlinuz_name="$(_dst_name ".vmlinuz")"
+    local dst_name=$(basename "$VM_DST_IMG")
 
-    cat >"${VM_README}" <<EOF
-If you have qemu installed (or in the SDK), you can start the image with:
-  cd path/to/image
+    _write_qemu_common "${script}"
+    sed -e "s%^VM_KERNEL=.*%VM_KERNEL='${vmlinuz_name}'%" \
+        -e "s%^VM_INITRD=.*%VM_INITRD='${dst_name}'%" -i "${script}"
 
-  qemu-kvm -m 1024 -kernel ${vmlinuz_name} -initrd ${dst_name} -append 'state=tmpfs: root=squashfs: sshkey="PUT AN SSH KEY HERE"'
+    cat >>"${VM_README}" <<EOF
 
+You can pass extra kernel parameters with -append, for example:
+  ./$(basename "${script}") -curses -append 'sshkey="PUT AN SSH KEY HERE"'
+
+When using -nograhic or -serial you must also enable the serial console:
+  ./$(basename "${script}") -nographic -append 'console=ttyS0,115200n8'
 EOF
-
-    VM_GENERATED_FILES+=( "${VM_README}" )
 }
 
 # Generate the vmware config file