[FAQ] need help on virtio-blk talk to spdk vhost #5580
Description
hello dear expert.
I suffer below error when I try start VM with spdk vhost to service virtio-blk
root@smc-hs219-01-salab:/mnt/nvme7n1/wayne/firecracker/firecracker/build/cargo_target/release/images# sh start-with-vhost.sh
net.ipv4.ip_forward = 1
2025-12-12T06:25:31.546104303 [anonymous-instance:main] Running Firecracker v1.15.0-dev
2025-12-12T06:25:31.546442126 [anonymous-instance:main] Listening on API socket ("/tmp/firecracker.socket").
2025-12-12T06:25:31.547421624 [anonymous-instance:fc_api] API server started.
2025-12-12T06:25:33.561517587 [anonymous-instance:fc_api] The API server received a Put request on "/boot-source" with body "{\n \"kernel_image_path\": \"./vmlinux-6.1.141\",\n \"boot_args\": \"console=ttyS0 reboot=k panic=1 pci=off ip=172.16.0.2::172.16.0.1:255.255.255.252::eth0:none nameserver=8.8.8.8\"\n}".
2025-12-12T06:25:33.561777963 [anonymous-instance:fc_api] The request was executed successfully. Status code: 204 No Content.
2025-12-12T06:25:33.578004937 [anonymous-instance:fc_api] The API server received a Put request on "/drives/rootfs" with body "{\n \"drive_id\": \"rootfs\",\n \"path_on_host\": \"./ubuntu-24.04.ext4\",\n \"is_root_device\": true,\n \"is_read_only\": false\n}".
2025-12-12T06:25:33.578632494 [anonymous-instance:fc_api] The request was executed successfully. Status code: 204 No Content.
2025-12-12T06:25:33.594963186 [anonymous-instance:fc_api] The API server received a Put request on "/drives/vhost_blk0" with body "{\n \"drive_id\": \"vhost_blk0\",\n \"socket\": \"/mnt/nvme7n1/wayne/firecracker/spdk/vhost_blk0\",\n \"is_root_device\": false,\n \"is_read_only\": false\n}".
2025-12-12T06:25:33.595238546 [anonymous-instance:fc_api] Received Error. Status code: 400 Bad Request. Message: Drive config error: Unable to create the virtio block device: Invalid block config.
{"fault_message":"Drive config error: Unable to create the virtio block device: Invalid block config."}2025-12-12T06:25:33.611499796 [anonymous-instance:fc_api] The API server received a Put request on "/network-interfaces/net1" with body "{\n \"iface_id\": \"net1\",\n \"guest_mac\": \"06:00:AC:10:00:02\",\n \"host_dev_name\": \"tap0\"\n}".
2025-12-12T06:25:33.612504472 [anonymous-instance:fc_api] The request was executed successfully. Status code: 204 No Content.
2025-12-12T06:25:33.628371882 [anonymous-instance:fc_api] The API server received a Put request on "/actions" with body "{\"action_type\": \"InstanceStart\"}".
2025-12-12T06:25:33.671234854 [anonymous-instance:main] Artificially kick devices
2025-12-12T06:25:33.671512134 [anonymous-instance:fc_vcpu 0] Received a VcpuEvent::Resume message with immediate_exit enabled. immediate_exit was disabled before proceeding
2025-12-12T06:25:33.671712787 [anonymous-instance:fc_api] The request was executed successfully. Status code: 204 No Content.
here is request I sent
# API 配置（静态 IP boot_args）
curl -s --unix-socket "${API_SOCKET}" -X PUT "http://localhost/boot-source" -H "Content-Type: application/json" -d '{
"kernel_image_path": "./vmlinux-6.1.141",
"boot_args": "console=ttyS0 reboot=k panic=1 pci=off ip=172.16.0.2::172.16.0.1:255.255.255.252::eth0:none nameserver=8.8.8.8"
}'
curl -s --unix-socket "${API_SOCKET}" -X PUT "http://localhost/drives/rootfs" -H "Content-Type: application/json" -d '{
"drive_id": "rootfs",
"path_on_host": "./ubuntu-24.04.ext4",
"is_root_device": true,
"is_read_only": false
}'
curl -s --unix-socket "${API_SOCKET}" -X PUT "http://localhost/drives/vhost_blk0" -H "Content-Type: application/json" -d '{
"drive_id": "vhost_blk0",
"socket": "/mnt/nvme7n1/wayne/firecracker/spdk/vhost_blk0",
"is_root_device": false,
"is_read_only": false
}'