Proxmox lxc add add linux.kernel_modules - kubernetes

Question

I am trying to setup an LXC container (debian) as a Kubernetes node.
I am so far that the only thing in the way is the kubeadm init script...
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "modprobe: ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file '/lib/modules/5.4.44-2-pve/modules.dep.bin'\nmodprobe: FATAL: Module configs not found in directory /lib/modules/5.4.44-2-pve\n", err: exit status 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher
After some research I figured out that I probably need to add the following: linux.kernel_modules: ip_tables,ip6_tables,netlink_diag,nf_nat,overlay
But adding this to /etc/pve/lxc/107.conf doesn't do anything.
Does anybody have a clue how to add the linux kernel modules?

Answer 1

To allow load with modprobe any modules inside privileged proxmox lxc container, you need add this options to container config:
lxc.apparmor.profile: unconfined
lxc.cgroup.devices.allow: a
lxc.cap.drop:
lxc.mount.auto: proc:rw sys:rw
lxc.mount.entry: /lib/modules lib/modules none bind 0 0
before that, you must first create the /lib/modules folder inside the container

Answer 2

I'm not sure what guide you are following but assuming that you have the required kernel modules on the host, this would do it:
lxc config set my-container linux.kernel_modules overlay
You can follow this guide from K3s too. Basically:
lxc config edit k3s-lxc
and
config:
linux.kernel_modules: ip_tables,ip6_tables,netlink_diag,nf_nat,overlay
raw.lxc: lxc.mount.auto=proc:rw sys:rw
security.privileged: "true"
security.nesting: "true"
✌️

Answer 3

For the fix ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file run from the host:
pct set $VMID --mp0 /usr/lib/modules/$(uname -r),mp=/lib/modules/$(uname -r),ro=1,backup=0
For the fix [ERROR SystemVerification]: failed to parse kernel config run from the host:
pct push $VMID /boot/config-$(uname -r) /boot/config-$(uname -r)
Where $VMID is your container id.