vnic-eth-hotplug cloud module

README.md

@@ -28,6 +28,7 @@ instance:
 Optional features, which may not be universally necessary:
 * manage symlinks from NVMe block devices to `/dev/xvd` and `/dev/sd` devices
   (i.e. AWS Nitro instances)
+* manage hotpluggable network interfaces
 * manage secondary IPv4 and IPv6 addresses on network interfaces
 
 ## Requirements
@@ -125,3 +126,9 @@ If you're instantiating an instance in order to create a new cloud image
 (using [Packer](https://packer.io), or some other means), you will need to
 remove this file before creating the image to ensure that instances using the
 new image will also run Tiny Cloud init scripts during their first boot.
+
+## Cloud Hotplug Modules
+
+### `vnic_eth_hotplug`
+
+### `nvme_ebs_links`

etc/network/interfaces.d/DEFAULT

@@ -0,0 +1,2 @@
+auto %%
+iface %% inet dhcp

etc/network/interfaces.d/lo

@@ -0,0 +1,2 @@
+auto lo
+iface lo inet loopback

lib/mdev/vnic-eth-hotplug

@@ -0,0 +1,109 @@
+#!/bin/sh
+# vim: set ts=4 et:
+
+set -e
+
+PROC="$(basename "$0")[$$]"
+
+DEBUG=
+
+log() {
+    [ -z "$DEBUG" ] && [ "$1" = "debug" ] && return
+    local facility="kern.$1"
+    shift
+    logger -p "$facility" -t "$PROC" "$@"
+}
+
+if [ -z "$MDEV" ]; then
+    log err "MDEV env not defined"
+    exit 1
+fi
+
+# where's the tiny-cloud lib directory?
+if [ -z "$TINY_CLOUD_LIBS" ]; then
+	TINY_CLOUD_CONF=${TINY_CLOUD_CONF:-/etc/conf.d/tiny-cloud}
+	[ -f "$TINY_CLOUD_CONF" ] && source "$TINY_CLOUD_CONF"
+	TINY_CLOUD_LIBS=${TINY_CLOUD_LIBS:-/lib/tiny-cloud}
+fi
+
+IFACE_CFG=/etc/network/interfaces
+
+ip() {
+    local v=-4 lev=info
+    if [ "$1" = '-4' ] || [ "$1" = '-6' ]; then
+        v="$1"
+        shift
+    fi
+    local op="$2"
+
+    [ "$op" = show ] && lev=debug
+    if /sbin/ip "$v" "$@" || [ -n "$FAIL_OK" ]; then
+        log "$lev" "OK: ip $v $*"
+    else
+        log err "FAIL: ip $v $*"
+    fi
+}
+
+assemble_interfaces() {
+    log info "Rebuilding $IFACE_CFG"
+    # TODO: might be elsewhere, source /etc/conf.d/tiny-cloud
+    "$TINY_CLOUD_LIBS"/network-interfaces
+}
+
+interface_up() {
+    log info "Bringing up $MDEV"
+    # so /run/udhcpcd.$MDEV.pid isn't non-owner writeable
+    (umask 0022 && ifup "$MDEV")
+}
+
+cleanup_interface() {
+    local v p rtable="${MDEV#eth}"
+    let rtable+=1000
+
+    log info "Cleaning up $MDEV"
+
+    # kill related udhcpc, don't panic if it's not there
+    kill "$(cat "/run/udhcpc.$MDEV.pid")" || true
+
+    # tidy up /run/ifstate, if it exists
+    [ -f /run/ifstate ] && sed -i -e "/^$MDEV=/d" /run/ifstate
+    rm -f /run/ifstate."$MDEV".lock
+
+    # remove related rules
+    for v in 4 6; do
+        for p in $(ip -"$v" rule show table "$rtable" | cut -d: -f1); do
+            ip -"$v" rule del pref "$p"
+        done
+    done
+}
+
+is_networking_started() { service networking status -q 2>/dev/null; }
+
+log info "STARTING: $ACTION $MDEV"
+
+if exec 200>>"$IFACE_CFG"; then
+    if flock 200; then
+        case $ACTION in
+            add|"")
+                assemble_interfaces
+                is_networking_started && interface_up
+                ;;
+            remove)
+                assemble_interfaces
+                is_networking_started && cleanup_interface
+                ;;
+            *)
+                log err "Unknown action '$ACTION'"
+                exit 1
+                ;;
+        esac
+    else
+        log err "Unable to flock $IFACE_CFG"
+        exit 1
+    fi
+else
+    log err "Unable to assign fd 200 to flock $IFACE_CFG"
+    exit 1
+fi
+
+log info "FINISHED: $ACTION $MDEV"

lib/tiny-cloud/aws/imds

@@ -22,6 +22,8 @@ _imds_header() {
 
 # digs deeper than the default
 imds_ssh_keys() {
+	local key
+
 	for key in $(imds "$IMDS_SSH_KEYS"); do
 		imds "$IMDS_SSH_KEYS/${key%=*}/openssh-key"
 	done | sort -u

lib/tiny-cloud/azure/imds

@@ -15,6 +15,8 @@ _imds_header() {
 
 # dig deeper than default
 imds_ssh_keys() {
+	local key
+
 	for key in $(imds "$IMDS_SSH_KEYS"); do
 		imds "$IMDS_SSH_KEYS/${key}/keyData"
 	done | sort -u

lib/tiny-cloud/gcp/imds

@@ -17,6 +17,8 @@ _imds_header() {
 
 # merge project and instance keys
 imds_ssh_keys() {
+	local ssh_keys
+
 	for ssh_keys in $IMDS_SSH_KEYS; do
 		# ignore errors and strip leading '<login>:'
 		_imds "$ssh_keys" | cut -d: -f2-

lib/tiny-cloud/init-early

@@ -15,10 +15,11 @@ expand_root() {
 	local volume=$(echo "$mountpoint" |
 		sed -Ee "s/(nvme\d+n\d|(xv|s)d[a-z])p?\d?$/\1/"
 	)
+	local partition
 
 	if [ "$mountpoint" != "$volume" ]; then
 		# it's a partition, resize it
-		local partition=$(echo "$mountpoint" | sed -Ee "s/.*(\d+)$/\1/")
+		partition=$(echo "$mountpoint" | sed -Ee "s/.*(\d+)$/\1/")
 		echo ", +" | sfdisk -q --no-reread -N "$partition" "$volume"
 		partx -u "$volume"
 	fi
@@ -27,12 +28,15 @@ expand_root() {
 	resize2fs "$mountpoint"
 }
 
+assemble_interfaces() { "$TINY_CLOUD_LIBS"/network-interfaces; }
+
 has_cloud_hotplugs() { [ -n "$HOTPLUG_MODULES" ]; }
 
 install_hotplugs() {
-	for module in $HOTPLUG_MODULES; do
+	local result
-		local result='-'
 
+	for module in $HOTPLUG_MODULES; do
+		result='-'
 		echo -n " $module"
 		if type "mod__$module" | grep -q "is a function"; then
 			"mod__$module" && result='+' || result='!'

lib/tiny-cloud/mdev

@@ -16,15 +16,18 @@ install_before() {
 	else
 		# no rule exists, put it before the catch-all fallback
 		before='^# fallback'
+		line="$line\n"
 	fi
 	sed -i -Ee "s|($before.*)|$line\n\1|" /etc/mdev.conf
 }
 
 # hotpluggable VNICs (multi-cloud)
 mod__vnic_eth_hotplug() {
-	# TODO: missing dependencies?  return 1
 	install_before '^eth' \
-		'eth[0-9]*		root:root 0644 */lib/mdev/vnic-eth-hotplug'
+		'eth[0-9]	root:root 0644 */lib/mdev/vnic-eth-hotplug'
+
+	# NICs attached at launch don't get added with mdev -s
+	assemble_interfaces
 }
 
 # load cloud-specific functions

lib/tiny-cloud/network-interfaces

@@ -0,0 +1,39 @@
+#!/bin/sh
+# vim: set ts=4 et:
+
+set -e
+
+IFACE_CFG=/etc/network/interfaces
+IFACE_DIR="${IFACE_CFG}.d"
+
+cd "$IFACE_DIR"
+
+cat > "$IFACE_CFG.new" <<EOT
+# NOTE: $0 rewrites this file.  Edit files in
+#       /etc/network/interfaces.d/ to persist any customizations.
+
+EOT
+
+# existing loopback and eths
+for i in /sys/class/net/{lo,eth*}; do
+    IFACE="$(basename "$i")"
+    [ ! -f "$IFACE" ] && sed -e "s/%%/$IFACE/g" DEFAULT > "$IFACE"
+    printf "%s\n\n" "$(cat "$IFACE")" >> "$IFACE_CFG.new"
+done
+
+# all the rest
+for i in "$IFACE_DIR"/*; do
+    IFACE="$(basename "$i")"
+    case $IFACE in
+        DEFAULT|lo|eth*)
+            continue
+            ;;
+        *)
+            printf "%s\n\n" "$(cat "$IFACE")" >> "$IFACE_CFG.new"
+            ;;
+    esac
+done
+
+# install new interfaces config
+[ -f "$IFACE_CFG" ] && cp -a "$IFACE_CFG" "$IFACE_CFG.bak"
+mv "$IFACE_CFG.new" "$IFACE_CFG"