set up kernel crashkernel for osbuild in kernel hook

osbuild is a tool to build OS images. It uses bwrap to install packages
inside a sandbox/container. Since the kernel package recommends
kexec-tools which in turn recommends grubby, the installation order would
be grubby -> kexec-tools -> kernel. So we can use the kernel hook
92-crashkernel.install provided by kexec-tools to set up kernel
crashkernel for the target OS image. But in osbuild's case, there is no
current running kernel and running `uname -r` in the container/sandbox
actually returns the host kernel release. To set up kernel crashkernel for
the OS image built by osbuild, a different logic is needed.

We will check if kernel hook is running inside the osbuild container
then set up kernel crashkernel only if osbuild hasn't specified a
custome value. osbuild exposes [1] the container=bwrap-osbuild environment
variable. According to [2], the environment variable is not inherited down
the process tree, so we need to check /proc/1/environ to detect this
environment variable to tell if the kernel hook is running inside a
bwrap-osbuild container. After that we need to know if osbuild wants to use
custom crashkernel value. This is done by checking if /etc/kernel/cmdline
has crashkernel set [3]. /etc/kernel/cmdline is written before packages
are installed.

[1] https://github.com/osbuild/osbuild/pull/926
[2] https://systemd.io/CONTAINER_INTERFACE/
[3] https://bugzilla.redhat.com/show_bug.cgi?id=2024976#c5

Reviewed-by: Pingfan Liu <piliu@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
This commit is contained in:
Coiby Xu 2021-12-15 21:45:18 +08:00
parent 5e8c751c39
commit ddd428a1d0

View File

@ -1576,6 +1576,11 @@ reset_crashkernel_after_update()
done done
} }
_is_osbuild()
{
[[ $(sed -n -E 's/.*(^|\s)container=(\S*).*/\2/p' < /proc/1/environ) == bwrap-osbuild ]]
}
reset_crashkernel_for_installed_kernel() reset_crashkernel_for_installed_kernel()
{ {
local _installed_kernel _running_kernel _crashkernel _crashkernel_running local _installed_kernel _running_kernel _crashkernel _crashkernel_running
@ -1585,6 +1590,11 @@ reset_crashkernel_for_installed_kernel()
exit 1 exit 1
fi fi
if _is_osbuild && ! grep -q crashkernel= /etc/kernel/cmdline; then
reset_crashkernel "--kernel=$_installed_kernel"
return
fi
if ! _running_kernel=$(_get_current_running_kernel_path); then if ! _running_kernel=$(_get_current_running_kernel_path); then
derror "Couldn't find current running kernel" derror "Couldn't find current running kernel"
exit exit