Synopsis: vmd fails to load config when boot kernel is used
Category: system
Environment:
System : OpenBSD 7.5
Details : OpenBSD 7.5 (GENERIC.MP) #82: Wed Mar 20 15:48:40
MDT 2024
dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP
Architecture: OpenBSD.amd64
Machine : amd64
Description:
I run a vmd(8) server where I will build OpenBSD images to test
different
setups. The process for building the base setup uses a
configuration
similar to the one below.
=== vm-build.conf
RD_PATH="/home/vms/_http/htdocs/pub/OpenBSD/7.5/amd64"
switch "build" {
interface bridge1
rdomain 5
group VMS
enable
}
vm "build-host" {
memory 512M
boot $RD_PATH "/bsd.rd"
interfaces 1
interface { switch "build" lladdr fe:e1:ba:00:00:01 }
disable
}
===
This configuration creates a "template" image which I then
extend when I
build the actual OpenBSD image using a command like.
vmctl start -c -B net -d `pwd`/vm.qcow2 \
-b /home/vms/_http/htdocs/pub/OpenBSD/7.5/amd64/bsd.rd
-t build-host newVM-build
However when I try to load the vm-build.conf config file I
receive the
following errors.
Jun 30 17:46:56 vmbsd vmd[34669]: no kernel or disk/cdrom
specified
How-To-Repeat:
Using the provided vm-build.conf and the vmctl(8) command from
OpenBSD
7.5 run the following command.
vmctl load `pwd`/vm-build.conf
Fix:
Reviewing changes to vmd/vmd.c 1.146 appears a change to how the
presence of a kernel load was tested for (line 1385).
Originally
it was testing for the presence of a kernel string, but change
to
check for the file descriptor. This change might be in
conjunction
with change vmd/parse.y 1.67. After the initial load of the
config
by parse.y, vm_register() is called. As part of the
vm_register()
function the disk, cdrom and kernel are checked (line 1421).
However
the kernel file has not been opened at this point so the file
handle
stored in vmc.vmc_kernel is still set to -1.
I am not sure if this change is correct as I am sure my summary
of
what I think is happening is missing plenty of understanding.
The
patch below changes the check in vm_register() to make sure the
a
boot option (kernel, disk, cdrom) was configured. With this
patch
I am again able to load the example config.
--- vmd.c.orig Tue Jul 2 14:42:39 2024
+++ vmd.c Tue Jul 2 14:46:13 2024
@@ -1418,8 +1418,7 @@
} else if (vmc->vmc_nnics > VM_MAX_NICS_PER_VM) {
log_warnx("invalid number of interfaces");
goto fail;
- } else if (vmc->vmc_kernel == -1 && vmc->vmc_ndisks == 0
- && strlen(vmc->vmc_cdrom) == 0) {
+ } else if ((vmc->vmc_flags &
(VMOP_CREATE_KERNEL|VMOP_CREATE_DISK|VMOP_CREATE_CDROM)) == 0) {
log_warnx("no kernel or disk/cdrom specified");
goto fail;
} else if (strlen(vcp->vcp_name) == 0) {
