Add LXD VM Guest Agent Support (#2145)

* Add LXD VM Guest Agent Support

* Add systemd patch, remove udev rules, change to kernel modules, fix linter

* Remove systemd patch, add conditionals to qemu-guest and lxd-agent

* Update buildroot-external/package/qemu-guest-agent/qemu-guest.service

Co-authored-by: Stefan Agner <stefan@agner.ch>

buildroot-external/Config.in

@@ -8,6 +8,7 @@ source "$BR2_EXTERNAL_HASSOS_PATH/package/khadas-boot/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/os-agent/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/pi-bluetooth/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/qemu-guest-agent/Config.in"
+source "$BR2_EXTERNAL_HASSOS_PATH/package/lxd-guest-agent/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/rpi-eeprom/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/rpi-rf-mod/Config.in"
 source "$BR2_EXTERNAL_HASSOS_PATH/package/rtl88x2bu/Config.in"

buildroot-external/board/pc/ova/kernel.config

@@ -16,6 +16,16 @@ CONFIG_VMWARE_VMCI=y
 CONFIG_VMWARE_BALLOON=y
 CONFIG_VMWARE_PVSCSI=y
 
+# These options are for LXD Guest Support
+CONFIG_NET_9P=m
+CONFIG_NET_9P_VIRTIO=m
+CONFIG_9P_FS=m
+CONFIG_9P_FS_POSIX_ACL=m
+CONFIG_PCI=y
+CONFIG_VSOCKETS=m
+CONFIG_VIRTIO_VSOCKETS_COMMON=m
+CONFIG_VHOST_VSOCK=m
+
 # VirtualBox
 CONFIG_VBOXGUEST=m
 

buildroot-external/configs/ova_defconfig

@@ -124,6 +124,7 @@ BR2_PACKAGE_HASSIO_MACHINE="qemux86-64"
 BR2_PACKAGE_OS_AGENT=y
 BR2_PACKAGE_OS_AGENT_BOARD="Ova"
 BR2_PACKAGE_QEMU_GUEST_AGENT=y
+BR2_PACKAGE_LXD_GUEST_AGENT=y
 BR2_PACKAGE_RPI_RF_MOD=y
 BR2_PACKAGE_RTL88X2BU=y
 BR2_PACKAGE_RTL8821CU=y

buildroot-external/package/lxd-guest-agent/Config.in

@@ -0,0 +1,9 @@
+config BR2_PACKAGE_LXD_GUEST_AGENT
+	bool "LXD Guest Agent"
+	depends on BR2_USE_MMU # libglib2
+	depends on BR2_USE_WCHAR # libglib2
+	depends on BR2_TOOLCHAIN_HAS_THREADS # libglib2
+	select BR2_PACKAGE_LIBGLIB2
+	select BR2_PACKAGE_ZLIB
+	help
+	  LXD guest agent for LXD based virtualisations

buildroot-external/package/lxd-guest-agent/lxd-agent-setup

@@ -0,0 +1,39 @@
+#!/bin/sh
+set -eu
+PREFIX="/run/lxd_agent"
+
+# Functions.
+mount_virtiofs() {
+    mount -t virtiofs config "${PREFIX}/.mnt" >/dev/null 2>&1
+}
+
+mount_9p() {
+    /sbin/modprobe 9pnet_virtio >/dev/null 2>&1 || true
+    /bin/mount -t 9p config "${PREFIX}/.mnt" -o access=0,trans=virtio >/dev/null 2>&1
+}
+
+fail() {
+    umount -l "${PREFIX}" >/dev/null 2>&1 || true
+    rmdir "${PREFIX}" >/dev/null 2>&1 || true
+    echo "${1}"
+    exit 1
+}
+
+# Setup the mount target.
+umount -l "${PREFIX}" >/dev/null 2>&1 || true
+mkdir -p "${PREFIX}"
+mount -t tmpfs tmpfs "${PREFIX}" -o mode=0700,size=50M
+mkdir -p "${PREFIX}/.mnt"
+
+# Try virtiofs first.
+mount_virtiofs || mount_9p || fail "Couldn't mount virtiofs or 9p, failing."
+
+# Copy the data.
+cp -Ra "${PREFIX}/.mnt/"* "${PREFIX}"
+
+# Unmount the temporary mount.
+umount "${PREFIX}/.mnt"
+rmdir "${PREFIX}/.mnt"
+
+# Fix up permissions.
+chown -R root:root "${PREFIX}"

buildroot-external/package/lxd-guest-agent/lxd-agent.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=LXD - agent
+After=syslog.target network.target
+ConditionPathExists=/dev/virtio-ports/org.linuxcontainers.lxd
+
+[Service]
+Type=notify
+WorkingDirectory=-/run/lxd_agent
+ExecStartPre=/usr/lib/systemd/lxd-agent-setup
+ExecStart=/run/lxd_agent/lxd-agent
+Restart=on-failure
+RestartSec=5s
+StartLimitInterval=60
+StartLimitBurst=10
+
+[Install]
+WantedBy=multi-user.target

buildroot-external/package/lxd-guest-agent/lxd-guest-agent.mk

@@ -0,0 +1,19 @@
+################################################################################
+#
+# lxd-guest-agent
+#
+################################################################################
+
+LXD_GUEST_AGENT_DEPENDENCIES = host-pkgconf
+
+define LXD_GUEST_AGENT_INSTALL_INIT_SYSTEMD
+	$(INSTALL) -D -m 644 $(LXD_GUEST_AGENT_PKGDIR)/lxd-agent.service \
+		$(TARGET_DIR)/usr/lib/systemd/system/lxd-agent.service
+	$(INSTALL) -D -m 755 $(LXD_GUEST_AGENT_PKGDIR)/lxd-agent-setup \
+		$(TARGET_DIR)/usr/lib/systemd/lxd-agent-setup
+	$(INSTALL) -d $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
+	ln -fs /usr/lib/systemd/system/lxd-agent.service \
+		$(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/lxd-agent.service
+endef
+
+$(eval $(generic-package))

buildroot-external/package/qemu-guest-agent/qemu-guest.service

@@ -3,6 +3,7 @@ Description=QEMU Guest Agent
 After=syslog.target network.target
 ConditionVirtualization=|kvm
 ConditionVirtualization=|qemu
+ConditionPathExists=!/dev/virtio-ports/org.linuxcontainers.lxd
 
 [Service]
 ExecStart=/usr/libexec/qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0