Description
Describe the bug
A recent Firecracker version seems to have introduced a regression.
The connection via tap device becomes quickly unreliable and unresponsive after boot (however, it works fine for a short time). I am just following the getting started guide, nothing fancy. I am on ARM64.
To Reproduce
[Author TODO: Steps to reproduce the behaviour:]
- Start Firecracker via
sudo ./firecracker-v1.11.0-aarch64 --config-file firecracker.conf --api-sock ./firecracker.socket - Configure Firecracker via
{
"boot-source": {
"kernel_image_path": "vmlinux-6.1.128",
"boot_args": "keep_bootcon console=ttyS0 reboot=k panic=1 pci=off"
},
"drives": [
{
"drive_id": "rootfs",
"is_root_device": true,
"is_read_only": false,
"path_on_host": "ubuntu-24.04.ext4"
}
],
"machine-config": null,
"cpu-config": null,
"balloon": null,
"network-interfaces": [
{
"iface_id": "net1",
"guest_mac": "06:00:AC:10:00:02",
"host_dev_name": "tap0"
}
],
"vsock": null,
"logger": {
"log_path": "./firecracker.log",
"level": "Debug",
"show_level": true,
"show_log_origin": true
},
"metrics": null,
"mmds-config": null,
"entropy": null
}
- Connect via SSH, it will fail after a few attempts
For some reason this config does not parse with v1.10.0. However I am pretty sure this version introduced the bug since it mentions changes with virtio-net.
The bug is not reproducible with v1.9.1
sudo ./firecracker-v1.9.1-aarch64 --config-file firecracker.conf --api-sock ./firecracker.socket
Expected behaviour
It remains possible to ssh into the device.
ping 172.16.0.2
should keep pinging, instead packets get delayed, dropped, etc.
Environment
[Author TODO: Please supply the following information):]
- Firecracker version: v1.10.0
- Host and guest kernel versions: host: 6.14.6-400.asahi.fc41.aarch64+16k, guest: 6.1.128
- Rootfs used: the one from the getting started guide
- Architecture: arm64
- Any other relevant software versions: N/A
Additional context
[Author TODO: How has this bug affected you?]
Not much just trying out Firecracker
[Author TODO: What are you trying to achieve?]
Just run the thing
[Author TODO: Do you have any idea of what the solution might be?]
Probably the virtio changes are related
Note that Ashai Linux uses 16K pages, which may have something to do with it
Checks
- Have you searched the Firecracker Issues database for similar problems?
- Have you read the existing relevant Firecracker documentation?
- Are you certain the bug being reported is a Firecracker issue?
According to @Manciukic this has not been reported yet.