EC2: Split off reusable configuration bits

Split ec2-base.conf into ec2-base.conf and a reusable ec2.conf,
similar to how Vagrant flavours share a common vagrant.conf.

releng/14.0 candidate.

Discussed with:	gjb
MFC after:	5 days
Sponsored by:	https://www.patreon.com/cperciva
Differential Revision:	https://reviews.freebsd.org/D41792

(cherry picked from commit fada6e2389fb62ff621a98fab7319e426da58b0b)

2 files changed, 130 insertions, 142 deletions

diff --git a/release/tools/ec2-base.conf b/release/tools/ec2-base.conf
index d033739adc26..f4c46fe285cd 100644
--- a/release/tools/ec2-base.conf
+++ b/release/tools/ec2-base.conf
@@ -1,78 +1,36 @@
 #!/bin/sh
-#
-#
 
-# Packages to install into the image we're creating.  This is a deliberately
-# minimalist set, providing only the packages necessary to bootstrap further
-# package installation as specified via EC2 user-data.
-export VM_EXTRA_PACKAGES="${VM_EXTRA_PACKAGES} ec2-scripts \
-	firstboot-freebsd-update firstboot-pkgs isc-dhcp44-client \
-	ebsnvme-id"
-
-# Include the amazon-ssm-agent package in amd64 images, since some users want
-# to be able to use it on systems which are not connected to the Internet.
-# (It is not enabled by default, however.)  This package does not exist for
-# aarch64, so we have to be selective about when we install it.
-if [ "${TARGET_ARCH}" = "amd64" ]; then
-	export VM_EXTRA_PACKAGES="${VM_EXTRA_PACKAGES} amazon-ssm-agent"
-fi
-
-# Set to a list of third-party software to enable in rc.conf(5).
-export VM_RC_LIST="ec2_configinit ec2_fetchkey ec2_loghostkey firstboot_freebsd_update firstboot_pkgs ntpd dev_aws_disk ec2_ephemeral_swap"
+. ${WORLDDIR}/release/tools/ec2.conf
 
-# Build with a 4.9 GB partition; the growfs rc.d script will expand
-# the partition to fill the root disk after the EC2 instance is launched.
-# Note that if this is set to <N>G, we will end up with an <N+1> GB disk
-# image since VMSIZE is the size of the filesystem partition, not the disk
-# which it resides within.
-export VMSIZE=5000m
+# Packages to install into the image we're creating.  In addition to packages
+# present on all EC2 AMIs, we install:
+# * ec2-scripts, which provides a range of EC2ification startup scripts,
+# * firstboot-freebsd-update, to install security updates at first boot,
+# * firstboot-pkgs, to install packages at first boot, and
+# * isc-dhcp44-client, used for IPv6 network setup.
+export VM_EXTRA_PACKAGES="${VM_EXTRA_PACKAGES} ec2-scripts \
+    firstboot-freebsd-update firstboot-pkgs isc-dhcp44-client"
 
-# No swap space; the ec2_ephemeralswap rc.d script will allocate swap
-# space on EC2 ephemeral disks.  (If they exist -- the T2 low-cost instances
-# and the C4 compute-optimized instances don't have ephemeral disks.  But
-# it would be silly to bloat the image and increase costs for every instance
-# just for those two families, especially since instances ranging in size
-# from 1 GB of RAM to 60 GB of RAM would need different sizes of swap space
-# anyway.)
-export NOSWAP=YES
+# Services to enable in rc.conf(5).
+export VM_RC_LIST="${VM_RC_LIST} ec2_configinit ec2_ephemeral_swap \
+    ec2_fetchkey ec2_loghostkey firstboot_freebsd_update firstboot_pkgs \
+    growfs sshd"
 
 vm_extra_pre_umount() {
-	# The firstboot_pkgs rc.d script will download the repository
-	# catalogue and install or update pkg when the instance first
-	# launches, so these files would just be replaced anyway; removing
-	# them from the image allows it to boot faster.
-	mount -t devfs devfs ${DESTDIR}/dev
-	chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
-		/usr/sbin/pkg delete -f -y pkg
-	umount ${DESTDIR}/dev
-	rm ${DESTDIR}/var/db/pkg/repo-*.sqlite
-
-	# The size of the EC2 root disk can be configured at instance launch
-	# time; expand our filesystem to fill the disk.
-	echo 'growfs_enable="YES"' >> ${DESTDIR}/etc/rc.conf
-
-	# EC2 instances use DHCP to get their network configuration.  IPv6
-	# requires accept_rtadv.
-	echo 'ifconfig_DEFAULT="SYNCDHCP accept_rtadv"' >> ${DESTDIR}/etc/rc.conf
-
-	# Unless the system has been configured via EC2 user-data, the user
-	# will need to SSH in to do anything.
-	echo 'sshd_enable="YES"' >> ${DESTDIR}/etc/rc.conf
-
 	# The AWS CLI tools are generally useful, and small enough that they
 	# will download quickly; but users will often override this setting
 	# via EC2 user-data.
 	echo 'firstboot_pkgs_list="devel/py-awscli"' >> ${DESTDIR}/etc/rc.conf
 
+	# EC2 instances use DHCP to get their network configuration.  IPv6
+	# requires accept_rtadv.
+	echo 'ifconfig_DEFAULT="SYNCDHCP accept_rtadv"' >> ${DESTDIR}/etc/rc.conf
+
 	# Enable IPv6 on all interfaces, and spawn DHCPv6 via rtsold
 	echo 'ipv6_activate_all_interfaces="YES"' >> ${DESTDIR}/etc/rc.conf
 	echo 'rtsold_enable="YES"' >> ${DESTDIR}/etc/rc.conf
 	echo 'rtsold_flags="-M /usr/local/libexec/rtsold-M -a"' >> ${DESTDIR}/etc/rc.conf
 
-	# Turn off IPv6 Duplicate Address Detection; the EC2 networking
-	# configuration makes it unnecessary.
-	echo 'net.inet6.ip6.dad_count=0' >> ${DESTDIR}/etc/sysctl.conf
-
 	# Provide a script which rtsold can use to launch DHCPv6
 	mkdir -p ${DESTDIR}/usr/local/libexec
 	cat > ${DESTDIR}/usr/local/libexec/rtsold-M <<'EOF'
@@ -82,94 +40,13 @@ vm_extra_pre_umount() {
 EOF
 	chmod 755 ${DESTDIR}/usr/local/libexec/rtsold-M
 
-	# The EC2 console is output-only, so while printing a backtrace can
-	# be useful, there's no point dropping into a debugger or waiting
-	# for a keypress.
-	echo 'debug.trace_on_panic=1' >> ${DESTDIR}/boot/loader.conf
-	echo 'debug.debugger_on_panic=0' >> ${DESTDIR}/boot/loader.conf
-	echo 'kern.panic_reboot_wait_time=0' >> ${DESTDIR}/boot/loader.conf
-
-	# The console is not interactive, so we might as well boot quickly.
-	echo 'autoboot_delay="-1"' >> ${DESTDIR}/boot/loader.conf
-	echo 'beastie_disable="YES"' >> ${DESTDIR}/boot/loader.conf
-
-	# Tell gptboot not to wait 3 seconds for a keypress which won't
-	# arrive either.
-	printf -- "-n\n" > ${DESTDIR}/boot.config
-
-	# The emulated keyboard attached to EC2 instances is inaccessible to
-	# users, and there is no mouse attached at all; disable to keyboard
-	# and the keyboard controller (to which the mouse would attach, if
-	# one existed) in order to save time in device probing.
-	echo 'hint.atkbd.0.disabled=1' >> ${DESTDIR}/boot/loader.conf
-	echo 'hint.atkbdc.0.disabled=1' >> ${DESTDIR}/boot/loader.conf
-
-	# EC2 has two consoles: An emulated serial port ("system log"),
-	# which has been present since 2006; and a VGA console ("instance
-	# screenshot") which was introduced in 2016.
-	echo 'boot_multicons="YES"' >> ${DESTDIR}/boot/loader.conf
-
-	# Some older EC2 hardware used a version of Xen with a bug in its
-	# emulated serial port.  It is not clear if EC2 still has any such
-	# nodes, but apply the workaround just in case.
-	echo 'hw.broken_txfifo="1"' >> ${DESTDIR}/boot/loader.conf
-
-	# Load the kernel module for the Amazon "Elastic Network Adapter"
-	echo 'if_ena_load="YES"' >> ${DESTDIR}/boot/loader.conf
-
-	# Use the "nda" driver for accessing NVMe disks rather than the
-	# historical "nvd" driver.
-	echo 'hw.nvme.use_nvd="0"' >> ${DESTDIR}/boot/loader.conf
-
-	# Disable KbdInteractiveAuthentication according to EC2 requirements.
-	sed -i '' -e \
-		's/^#KbdInteractiveAuthentication yes/KbdInteractiveAuthentication no/' \
-		${DESTDIR}/etc/ssh/sshd_config
-
-	# Use FreeBSD Update mirrors hosted in AWS
-	sed -i '' -e 's/update.FreeBSD.org/aws.update.FreeBSD.org/' \
-		${DESTDIR}/etc/freebsd-update.conf
-
-	# Use the NTP service provided by Amazon
-	sed -i '' -e 's/^pool/#pool/' \
-		-e '1,/^#server/s/^#server.*/server 169.254.169.123 iburst/' \
-		${DESTDIR}/etc/ntp.conf
-
-	# Provide a map for accessing Elastic File System mounts
-	cat > ${DESTDIR}/etc/autofs/special_efs <<'EOF'
-#!/bin/sh
-
-if [ $# -eq 0 ]; then
-        # No way to know which EFS filesystems exist and are
-        # accessible to this EC2 instance.
-        exit 0
-fi
-
-# Provide instructions on how to mount the requested filesystem.
-FS=$1
-REGION=`fetch -qo- http://169.254.169.254/latest/meta-data/placement/availability-zone | sed -e 's/[a-z]$//'`
-echo "-nfsv4,minorversion=1,oneopenown ${FS}.efs.${REGION}.amazonaws.com:/"
-EOF
-	chmod 755 ${DESTDIR}/etc/autofs/special_efs
-
-	# The first time the AMI boots, the installed "first boot" scripts
-	# should be allowed to run:
-	# * ec2_configinit (download and process EC2 user-data)
-	# * ec2_fetchkey (arrange for SSH using the EC2-provided public key)
-	# * growfs (expand the filesystem to fill the provided disk)
-	# * firstboot_freebsd_update (install critical updates)
-	# * firstboot_pkgs (install packages)
-	touch ${DESTDIR}/firstboot
-
 	# Any EC2 ephemeral disks seen when the system first boots will
 	# be "new" disks; there is no "previous boot" when they might have
 	# been seen and used already.
 	touch ${DESTDIR}/var/db/ec2_ephemeral_diskseen
 
-	if ! [ -z "${QEMUSTATIC}" ]; then
-		rm -f ${DESTDIR}/${EMULATOR}
-	fi
-	rm -f ${DESTDIR}/etc/resolv.conf
+	# Configuration common to all EC2 AMIs
+	ec2_common
 
 	return 0
 }
diff --git a/release/tools/ec2.conf b/release/tools/ec2.conf
new file mode 100644
index 000000000000..a233bf5981c1
--- /dev/null
+++ b/release/tools/ec2.conf
@@ -0,0 +1,111 @@
+#!/bin/sh
+
+# Packages which should be installed onto all EC2 AMIs:
+# * ebsnvme-id, which is very minimal and provides important EBS-specific
+# functionality,
+# * amazon-ssm-agent (not enabled by default, but some users need to use
+# it on systems not connected to the internet).
+export VM_EXTRA_PACKAGES="${VM_EXTRA_PACKAGES} ebsnvme-id amazon-ssm-agent"
+
+# Services which should be enabled by default in rc.conf(5).
+export VM_RC_LIST="dev_aws_disk ntpd"
+
+# Build with a 4.9 GB partition; the growfs rc.d script will expand
+# the partition to fill the root disk after the EC2 instance is launched.
+# Note that if this is set to <N>G, we will end up with an <N+1> GB disk
+# image since VMSIZE is the size of the filesystem partition, not the disk
+# which it resides within.
+export VMSIZE=5000m
+
+# No swap space; it doesn't make sense to provision any as part of the disk
+# image when we could be launching onto a system with anywhere between 0.5
+# and 4096 GB of RAM.
+export NOSWAP=YES
+
+ec2_common() {
+	# Delete the pkg package and the repo database; they will likely be
+	# long out of date before the EC2 instance is launched.
+	mount -t devfs devfs ${DESTDIR}/dev
+	chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
+		/usr/sbin/pkg delete -f -y pkg
+	umount ${DESTDIR}/dev
+	rm ${DESTDIR}/var/db/pkg/repo-*.sqlite
+
+	# Turn off IPv6 Duplicate Address Detection; the EC2 networking
+	# configuration makes it unnecessary.
+	echo 'net.inet6.ip6.dad_count=0' >> ${DESTDIR}/etc/sysctl.conf
+
+	# Booting quickly is more important than giving users a chance to
+	# access the boot loader via the serial port.
+	echo 'autoboot_delay="-1"' >> ${DESTDIR}/boot/loader.conf
+	echo 'beastie_disable="YES"' >> ${DESTDIR}/boot/loader.conf
+
+	# Tell gptboot not to wait 3 seconds for a keypress which will
+	# never arrive.
+	printf -- "-n\n" > ${DESTDIR}/boot.config
+
+	# The emulated keyboard attached to EC2 instances is inaccessible to
+	# users, and there is no mouse attached at all; disable to keyboard
+	# and the keyboard controller (to which the mouse would attach, if
+	# one existed) in order to save time in device probing.
+	echo 'hint.atkbd.0.disabled=1' >> ${DESTDIR}/boot/loader.conf
+	echo 'hint.atkbdc.0.disabled=1' >> ${DESTDIR}/boot/loader.conf
+
+	# EC2 has two consoles: An emulated serial port ("system log"),
+	# which has been present since 2006; and a VGA console ("instance
+	# screenshot") which was introduced in 2016.
+	echo 'boot_multicons="YES"' >> ${DESTDIR}/boot/loader.conf
+
+	# Some older EC2 hardware used a version of Xen with a bug in its
+	# emulated serial port.  It is not clear if EC2 still has any such
+	# nodes, but apply the workaround just in case.
+	echo 'hw.broken_txfifo="1"' >> ${DESTDIR}/boot/loader.conf
+
+	# Load the kernel module for the Amazon "Elastic Network Adapter"
+	echo 'if_ena_load="YES"' >> ${DESTDIR}/boot/loader.conf
+
+	# Use the "nda" driver for accessing NVMe disks rather than the
+	# historical "nvd" driver.
+	echo 'hw.nvme.use_nvd="0"' >> ${DESTDIR}/boot/loader.conf
+
+	# Disable KbdInteractiveAuthentication according to EC2 requirements.
+	sed -i '' -e \
+		's/^#KbdInteractiveAuthentication yes/KbdInteractiveAuthentication no/' \
+		${DESTDIR}/etc/ssh/sshd_config
+
+	# Use FreeBSD Update mirrors hosted in AWS
+	sed -i '' -e 's/update.FreeBSD.org/aws.update.FreeBSD.org/' \
+		${DESTDIR}/etc/freebsd-update.conf
+
+	# Use the NTP service provided by Amazon
+	sed -i '' -e 's/^pool/#pool/' \
+		-e '1,/^#server/s/^#server.*/server 169.254.169.123 iburst/' \
+		${DESTDIR}/etc/ntp.conf
+
+	# Provide a map for accessing Elastic File System mounts
+	cat > ${DESTDIR}/etc/autofs/special_efs <<'EOF'
+#!/bin/sh
+
+if [ $# -eq 0 ]; then
+        # No way to know which EFS filesystems exist and are
+        # accessible to this EC2 instance.
+        exit 0
+fi
+
+# Provide instructions on how to mount the requested filesystem.
+FS=$1
+REGION=`fetch -qo- http://169.254.169.254/latest/meta-data/placement/availability-zone | sed -e 's/[a-z]$//'`
+echo "-nfsv4,minorversion=1,oneopenown ${FS}.efs.${REGION}.amazonaws.com:/"
+EOF
+	chmod 755 ${DESTDIR}/etc/autofs/special_efs
+
+	# The first time the AMI boots, run "first boot" scripts.
+	touch ${DESTDIR}/firstboot
+
+	if ! [ -z "${QEMUSTATIC}" ]; then
+		rm -f ${DESTDIR}/${EMULATOR}
+	fi
+	rm -f ${DESTDIR}/etc/resolv.conf
+
+	return 0
+}