Add customize workflow

This commit is contained in:
Thales Maciel 2026-01-29 19:29:13 -03:00
parent e10a51558e
commit dee329cf39
No known key found for this signature in database
GPG key ID: 33112E6833C34679

246
customize.sh Executable file
View file

@ -0,0 +1,246 @@
#!/usr/bin/env bash
set -euo pipefail
log() {
printf '[customize] %s\n' "$*"
}
usage() {
cat <<'EOF'
Usage: ./customize.sh <output-rootfs> [--size <size>]
Creates a copy of rootfs.ext4, optionally resizes it, boots a VM with the
copy as a writable rootfs, then applies base configuration and packages.
EOF
}
parse_size() {
local raw="$1"
if [[ "$raw" =~ ^([0-9]+)([KMG])?$ ]]; then
local num="${BASH_REMATCH[1]}"
local unit="${BASH_REMATCH[2]}"
case "$unit" in
K) echo $((num * 1024)) ;;
M|"") echo $((num * 1024 * 1024)) ;;
G) echo $((num * 1024 * 1024 * 1024)) ;;
esac
return 0
fi
return 1
}
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
STATE="$DIR/state"
VM_ROOT="$STATE/vms"
mkdir -p "$VM_ROOT"
BASE_ROOTFS="$DIR/rootfs.ext4"
FC_BIN="$DIR/firecracker"
KERNEL="$DIR/vmlinux"
SSH_KEY="$DIR/id_ed25519"
BR_DEV="br-fc"
BR_IP="172.16.0.1"
CIDR="24"
DNS_SERVER="1.1.1.1"
OUT_ROOTFS=""
SIZE_SPEC=""
while [[ $# -gt 0 ]]; do
case "$1" in
--size)
SIZE_SPEC="${2:-}"
shift 2
;;
-h|--help)
usage
exit 0
;;
*)
if [[ -z "$OUT_ROOTFS" ]]; then
OUT_ROOTFS="$1"
shift
else
log "unknown option: $1"
usage
exit 1
fi
;;
esac
done
if [[ -z "$OUT_ROOTFS" ]]; then
usage
exit 1
fi
if [[ ! -f "$BASE_ROOTFS" ]]; then
log "base rootfs not found: $BASE_ROOTFS"
exit 1
fi
if [[ -e "$OUT_ROOTFS" ]]; then
log "output rootfs already exists: $OUT_ROOTFS"
exit 1
fi
if ! command -v resize2fs >/dev/null 2>&1; then
log "resize2fs required"
exit 1
fi
log "copying base rootfs to $OUT_ROOTFS"
cp --reflink=auto "$BASE_ROOTFS" "$OUT_ROOTFS"
if [[ -n "$SIZE_SPEC" ]]; then
SIZE_BYTES="$(parse_size "$SIZE_SPEC")"
BASE_BYTES="$(stat -c%s "$BASE_ROOTFS")"
if [[ -z "$SIZE_BYTES" || "$SIZE_BYTES" -lt "$BASE_BYTES" ]]; then
log "size must be >= base image size"
exit 1
fi
log "resizing rootfs to $SIZE_SPEC"
truncate -s "$SIZE_BYTES" "$OUT_ROOTFS"
e2fsck -p -f "$OUT_ROOTFS" >/dev/null
resize2fs "$OUT_ROOTFS" >/dev/null
fi
VM_ID="$(head -c 32 /dev/urandom | xxd -p -c 256)"
VM_TAG="${VM_ID:0:8}"
VM_NAME="customize-${VM_TAG}"
VM_DIR="$VM_ROOT/$VM_ID"
mkdir -p "$VM_DIR"
API_SOCK="${XDG_RUNTIME_DIR:-/run/user/$(id -u)}/banger/fc-$VM_TAG.sock"
LOG_FILE="$VM_DIR/firecracker.log"
TAP_DEV="tap-fc-$VM_TAG"
# Allocate guest IP
NEXT_IP_FILE="$STATE/next_ip"
NEXT_IP="$(cat "$NEXT_IP_FILE" 2>/dev/null || echo 2)"
GUEST_IP="172.16.0.$NEXT_IP"
echo "$((NEXT_IP + 1))" > "$NEXT_IP_FILE"
sudo -v
cleanup() {
sudo kill "${FC_PID:-}" 2>/dev/null || true
sudo ip link del "$TAP_DEV" 2>/dev/null || true
rm -f "$API_SOCK"
rm -rf "$VM_DIR"
}
trap cleanup EXIT
sudo mkdir -p "$(dirname "$API_SOCK")"
sudo chown "$(id -u):$(id -g)" "$(dirname "$API_SOCK")"
# Host bridge
if ! ip link show "$BR_DEV" >/dev/null 2>&1; then
log "creating host bridge $BR_DEV ($BR_IP/$CIDR)"
sudo ip link add name "$BR_DEV" type bridge
sudo ip addr add "${BR_IP}/${CIDR}" dev "$BR_DEV"
sudo ip link set "$BR_DEV" up
else
sudo ip link set "$BR_DEV" up
fi
log "creating tap device $TAP_DEV"
TAP_USER="${SUDO_UID:-$(id -u)}"
TAP_GROUP="${SUDO_GID:-$(id -g)}"
sudo ip tuntap add dev "$TAP_DEV" mode tap user "$TAP_USER" group "$TAP_GROUP"
sudo ip link set "$TAP_DEV" master "$BR_DEV"
sudo ip link set "$TAP_DEV" up
sudo ip link set "$BR_DEV" up
log "starting firecracker process"
rm -f "$API_SOCK"
nohup sudo -E "$FC_BIN" --api-sock "$API_SOCK" >"$LOG_FILE" 2>&1 &
FC_PID="$!"
log "waiting for firecracker api socket"
for _ in $(seq 1 200); do
[[ -S "$API_SOCK" ]] && break
sleep 0.02
done
[[ -S "$API_SOCK" ]] || { log "firecracker api socket not ready"; exit 1; }
cat > "$VM_DIR/info" <<EOF
id=$VM_ID
name=$VM_NAME
pid=$FC_PID
created_at=$(date -Iseconds)
guest_ip=$GUEST_IP
tap=$TAP_DEV
api_sock=$API_SOCK
log=$LOG_FILE
EOF
log "configuring machine"
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/machine-config \
-H "Content-Type: application/json" \
-d '{
"vcpu_count": 2,
"mem_size_mib": 1024,
"smt": false
}' >/dev/null
KCMD="console=ttyS0 reboot=k panic=1 pci=off root=/dev/vda rw ip=${GUEST_IP}::${BR_IP}:255.255.255.0:${VM_NAME}:eth0:off:${DNS_SERVER} hostname=${VM_NAME}"
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/boot-source \
-H "Content-Type: application/json" \
-d "{
\"kernel_image_path\": \"$KERNEL\",
\"boot_args\": \"$KCMD\"
}" >/dev/null
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/drives/rootfs \
-H "Content-Type: application/json" \
-d "{
\"drive_id\": \"rootfs\",
\"path_on_host\": \"$OUT_ROOTFS\",
\"is_root_device\": true,
\"is_read_only\": false
}" >/dev/null
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/network-interfaces/eth0 \
-H "Content-Type: application/json" \
-d "{
\"iface_id\": \"eth0\",
\"host_dev_name\": \"$TAP_DEV\"
}" >/dev/null
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/actions \
-H "Content-Type: application/json" \
-d '{ "action_type": "InstanceStart" }' >/dev/null
log "enabling NAT for customization"
sudo -E ./nat.sh up "$VM_TAG" >/dev/null
log "waiting for SSH"
for _ in $(seq 1 60); do
if ssh -i "$SSH_KEY" -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null \
"root@${GUEST_IP}" "true" >/dev/null 2>&1; then
break
fi
sleep 1
done
log "configuring guest"
ssh -i "$SSH_KEY" -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null \
"root@${GUEST_IP}" bash -lc "set -e
printf 'nameserver %s\n' \"$DNS_SERVER\" > /etc/resolv.conf
echo \"$VM_NAME\" > /etc/hostname
printf '127.0.0.1 localhost\n127.0.1.1 %s\n' \"$VM_NAME\" > /etc/hosts
apt-get update
DEBIAN_FRONTEND=noninteractive apt-get -y upgrade
DEBIAN_FRONTEND=noninteractive apt-get -y install git less tree ca-certificates curl
git config --system init.defaultBranch main
"
log "customization complete; shutting down"
sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/actions \
-H "Content-Type: application/json" \
-d '{ "action_type": "SendCtrlAltDel" }' >/dev/null || true
sleep 2
log "done"