overlay.d: create new 25-azure-udev-rules overlay

We previously had the 68-azure-sriov-nm-unmanaged.rules but we
figured out we also want those rules in the initramfs. This
commit makes a new overlay.d entry and groups together a new
dracut module along with the udev rules in that overlay.d directory.

Fixes coreos/fedora-coreos-tracker#1383

manifests/fedora-coreos-base.yaml

@@ -20,6 +20,7 @@ ostree-layers:
   - overlay/08nouveau
   - overlay/09misc
   - overlay/20platform-chrony
+  - overlay/25-azure-udev-rules
 
 # Be minimal
 recommends: false

overlay.d/25-azure-udev-rules/statoverride

@@ -0,0 +1,2 @@
+# Config file for overriding permission bits on overlay files/dirs
+# Format: =<file mode in decimal> <absolute path to a file or directory>

overlay.d/25-azure-udev-rules/usr/lib/dracut/modules.d/25azure-udev-rules/module-setup.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/bash
+# Install 68-azure-sriov-nm-unmanaged.rules into the initramfs
+
+# called by dracut
+check() {
+    return 0
+}
+
+# called by dracut
+depends() {
+    return 0
+}
+
+# called by dracut
+install() {
+    inst_rules 68-azure-sriov-nm-unmanaged.rules
+}

overlay.d/README.md

@@ -53,3 +53,16 @@ Add static chrony configuration for NTP servers provided on platforms
 such as `azure`, `aws`, `gcp`. The chrony config for these NTP servers
 should override other chrony configuration (e.g. DHCP-provided)
 configuration.
+
+25-azure-udev-rules
+-------------------
+
+Add udev rules for SRIOV networking on Azure. The udev rules are also
+needed in the initramfs [1] and are delivered here via a dracut
+module. This may be able to be removed once an upstream PR [2]
+merges, though we need to make sure the RPM [3] includes the dracut
+bits to include the rules in the initramfs too.
+
+[1] https://github.com/coreos/fedora-coreos-tracker/issues/1383
+[2] https://github.com/Azure/WALinuxAgent/pull/1622
+[3] https://src.fedoraproject.org/rpms/WALinuxAgent/pull-request/4