MTL-2364 Change /var/lib/containerd from an OverlayFS to a Conventi…

…onal Partition (#36)

remove overlayfs

mount CONLIB at /var/lib/containerd

update README

93metaldmk8s/metal-dmk8s-lib.sh

@@ -98,17 +98,14 @@ make_ephemeral() {
     _trip_udev
     mkfs.xfs -f -L ${metal_k8slet#*=} "/dev/${target}${nvme:+p}3" || metal_dmk8s_die "Failed to create ${metal_k8slet#*=}"
 
-    mkdir -p /run/containerd /var/lib/kubelet /var/lib/containerd /run/lib-containerd
+    mkdir -p /run/containerd /var/lib/kubelet /var/lib/containerd
     {
         printf '% -18s\t% -18s\t%s\t%s 0 0\n' "${metal_conrun}" /run/containerd xfs "$metal_fsopts_xfs"
-        printf '% -18s\t% -18s\t%s\t%s 0 0\n' "${metal_conlib}" /run/lib-containerd xfs "$metal_fsopts_xfs"
+        printf '% -18s\t% -18s\t%s\t%s 0 0\n' "${metal_conlib}" /var/lib/containerd xfs "$metal_fsopts_xfs"
         printf '% -18s\t% -18s\t%s\t%s 0 0\n' "${metal_k8slet}" /var/lib/kubelet xfs "$metal_fsopts_xfs"
     } >>$metal_fstab
 
-    # Mount FS to allow creation of necessary overlayFS directories; might as well mount everything with -a.
-    mount -a -v -T $metal_fstab && mkdir -p /run/lib-containerd/ovlwork /run/lib-containerd/overlayfs
-    printf '% -18s\t% -18s\t%s\t%s 0 0\n' containerd_overlayfs /var/lib/containerd overlay lowerdir=/var/lib/containerd,upperdir=/run/lib-containerd/overlayfs,workdir=/run/lib-containerd/ovlwork >>$metal_fstab
-    # Mount FS again, catching our new overlayFS. Failure to mount here is fatal.
+    # Mount filesystems. Failure to mount here is fatal.
     mount -a -v -T $metal_fstab
 
     # echo 1 to signal that this module create a disk.

README.md

@@ -4,11 +4,10 @@ This module deploys an ephemeral disk to be used by kubernetes containers:
 
 - `/run/containerd` partition
 - `/var/lib/kubelet` partition
-- `/run/lib-containerd` partition
+- `/var/lib/containerd` partition
 
 ## Table of Contents
 
-- [OverlayFS](README.md#overlayfs)
 - [Parameters](README.md#parameters)
     - [Customizable Parameters](README.md#customizable-parameters) 
         - [FSLabel Parameters](README.md#fslabel-parameters)
@@ -22,21 +21,6 @@ This module deploys an ephemeral disk to be used by kubernetes containers:
     - [Required Parameters](README.md#required-parameters)
     - [`metal.server`](README.md#metalserver)
 
-## OverlayFS
-
-In order to allow reading of the original material in `/var/lib/containerd` residing in the SquashFS image while offering persistent storage, an overlayFS is created.
-
-Only `/var/lib/containerd` is an OverlayFS.
-- Lower Directory (Read-Only): `/var/lib/containerd`
-- Upper Directory (Writeable): `/run/lib-containerd`
-
-> Existing data from the root OverlayFS and the squashFS will be read-only at that location once the `containerd_overlayfs` is mounted.
-
-For more information on the OverlayFS, see:
-- [90metalmdsquash](https://github.com/Cray-HPE/dracut-metal-mdsquash#rootfs-and-the-persistent-overlayfs)
-- [CSM Usage of OverlayFS](https://github.com/Cray-HPE/docs-csm/blob/main/background/ncn_mounts_and_file_systems.md)
-- [Kernel Documentation on OverlayFS](https://www.kernel.org/doc/html/latest/filesystems/overlayfs.html)
-
 ## Parameters
 
 The `unit` of size varies per-parameter; pay attention to avoid undesirable partition tables
@@ -55,7 +39,7 @@ This may be desirable for cases when another LVM is being re-used.
 
 ##### `metal.disk.conlib`
 
-> FSLabel for the `/run/lib-containerd`.
+> FSLabel for the `/var/lib/containerd`.
 > - `Default: CONLIB`
 
 ##### `metal.disk.k8slet`
@@ -74,7 +58,7 @@ This may be desirable for cases when another LVM is being re-used.
 
 ##### `metal.disk.conlib.size` 
 
-> Size of the `/run/lib-containerd` partition, measured in percentage (`%`):
+> Size of the `/var/lib/containerd` partition, measured in percentage (`%`):
 > - `Default: 40`
 > - `Min: 10`
 > - `Max: 45`