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Thales Maciel 2026-01-21 18:45:45 -03:00
commit 50c851cf07
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136
run.sh Executable file
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#!/usr/bin/env bash
set -euo pipefail
log() {
printf '[spawn] %s\n' "$*"
}
log "starting"
DIR="$(pwd)"
STATE="$DIR/state"
mkdir -p "$STATE"
FC_BIN="$DIR/firecracker"
KERNEL="$DIR/vmlinux"
ROOTFS="$DIR/rootfs.ext4"
SSH_KEY="$DIR/id_ed25519"
BR_DEV="br-fc"
BR_IP="172.16.0.1"
CIDR="24"
VM_ID="$(date +%s)-$$"
VM_DIR="$STATE/vm-$VM_ID"
mkdir -p "$VM_DIR"
API_SOCK="$VM_DIR/firecracker.sock"
LOG_FILE="$VM_DIR/firecracker.log"
TAP_DEV="tap-fc-$VM_ID"
# 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"
log "vm id: $VM_ID"
log "allocated guest ip: $GUEST_IP"
sudo -v
# Host bridge
if ! ip link show "$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
log "host bridge $BR_DEV already exists"
fi
# Per-VM TAP
log "creating tap device $TAP_DEV"
sudo ip tuntap add dev "$TAP_DEV" mode tap
sudo ip link set "$TAP_DEV" master "$BR_DEV"
sudo ip link set "$TAP_DEV" up
# Start Firecracker
log "starting firecracker process"
rm -f "$API_SOCK"
nohup "$FC_BIN" --api-sock "$API_SOCK" >"$LOG_FILE" 2>&1 &
FC_PID="$!"
echo "$FC_PID" > "$VM_DIR/pid"
log "firecracker pid: $FC_PID"
# Wait for API socket
log "waiting for firecracker api socket"
for _ in $(seq 1 200); do
[[ -S "$API_SOCK" ]] && break
sleep 0.02
done
[[ -S "$API_SOCK" ]] || { log "firecracker api socket not ready"; exit 1; }
log "api socket ready"
# Machine config
log "configuring machine"
curl --unix-socket "$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
# Boot source
log "configuring boot source"
KCMD="console=ttyS0 reboot=k panic=1 pci=off root=/dev/vda rw ip=${GUEST_IP}::${BR_IP}:255.255.255.0::eth0:off"
curl --unix-socket "$API_SOCK" -X PUT http://localhost/boot-source \
-H "Content-Type: application/json" \
-d "{
\"kernel_image_path\": \"$KERNEL\",
\"boot_args\": \"$KCMD\"
}" >/dev/null
# Root filesystem
log "attaching root filesystem"
curl --unix-socket "$API_SOCK" -X PUT http://localhost/drives/rootfs \
-H "Content-Type: application/json" \
-d "{
\"drive_id\": \"rootfs\",
\"path_on_host\": \"$ROOTFS\",
\"is_root_device\": true,
\"is_read_only\": false
}" >/dev/null
# Network interface
log "configuring network interface"
curl --unix-socket "$API_SOCK" -X PUT http://localhost/network-interfaces/eth0 \
-H "Content-Type: application/json" \
-d "{
\"iface_id\": \"eth0\",
\"host_dev_name\": \"$TAP_DEV\"
}" >/dev/null
# Start VM
log "starting virtual machine"
curl --unix-socket "$API_SOCK" -X PUT http://localhost/actions \
-H "Content-Type: application/json" \
-d '{ "action_type": "InstanceStart" }' >/dev/null
cat > "$VM_DIR/info" <<EOF
vm_id=$VM_ID
pid=$FC_PID
guest_ip=$GUEST_IP
tap=$TAP_DEV
api_sock=$API_SOCK
log=$LOG_FILE
EOF
log "vm started successfully"
log "guest ip: $GUEST_IP"
log "ssh: ssh -i \"$SSH_KEY\" root@$GUEST_IP"
log "logs: $LOG_FILE"
log "done"