[Libguestfs] Re: appliance not getting ipv4 assigned when host kernel has CONFIG_IPV6_SIT builtin

Hello all, I am encountering an issue with virt-customize when the host kernel, on which virt-customize runs, has CONFIG_IPV6_SIT built-in. Below is the error output from the command: virt-customize -a noble-server-cloudimg-amd64.qcow2 --install isc-dhcp-client [

Using the -v verbose option, I discovered that the IP address assigned in the QEMU command line was not reflected inside the guest. Here is the relevant ip a output from the log:

+ ip a 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 brd 127.255.255.255 scope host lo valid_lft forever preferred_lft forever inet6 ::1 /128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff inet6 fe80::5054:ff:fe12:3456/64 scope link tentative valid_lft forever preferred_lft forever 3: sit0@NONE: mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000 link/sit 0.0.0.0 brd 0.0.0.0 inet6 ::127.0.0.1/96 scope host valid_lft forever preferred_lft forever Further debugging revealed that when the host kernel has SIT-related configurations enabled (i.e., CONFIG_IPV6_SIT), the supermin appliance, which libguestfs uses, inherits the same kernel and initrd. Consequently, the guest environment booted by virt-customize includes the sit0 device. When the sit0 device is present, the primary NIC (eth0) does not receive the static IP address assigned by libguestfs in the QEMU command line: /usr/bin/qemu-system-x86_64 \ -global virtio-blk-pci.scsi=off \ ... -netdev user,id=usernet,net=169.254.2.15/16 \ -device virtio-net-pci,netdev=usernet \ ..

I verified this issue on another machine where the host kernel had no SIT-related configurations enabled. On that machine, the same virt-customize command with the same Noble image worked correctly. I have attached verbose logs for both working and non-working configurations. A diff of these logs shows that the sit0 device causes the IP assignment issue with the eth0 interface. I have the following queries and would appreciate any responses: 1. Why does the user network IP not get applied when the sit0 device is present in the appliance? 2. Is there a way to append parameters to the libguestfs QEMU command line to blacklist the sit module in such cases? 3. Can we override the kernel and initrd used by libguestfs via the virt-customize command line?

libguestfs: command: run: passt --help sh: 1: passt: not found