proxmox-if-mtu-setup.sh

proxmox-if-mtu-setup.sh

#!/bin/bash

export HOSTNAME=$(/usr/bin/hostname -A)
export LOG_FACILITY="user.6"
LOG_FILE="net-if-setup.log"
LOG_PATH="/var/log"
export FLP="${LOG_PATH}/${LOG_FILE}"
IFNAME="enx803f5df75c57"
BRNAME="vmbr0"
MTU="9000"
REACHABILITY_TEST_ADDR="10.8.4.1"
REACHABILITY_TEST_COUNT="4"
REACHABILITY_TEST_PCT_FILE="/tmp/reachability_target_pct"
REACHABILITY_TEST_MAC_FILE="/tmp/reachability_target_mac"
WAIT_TIME=5

function dlog() {
	local msg="$1"; /usr/bin/logger -t "${HOSTNAME}" -p "${LOG_FACILITY}" "${msg}";
	NOW=$(/usr/bin/date +"%d-%m-%Y %T"); echo "${NOW} ${msg}" >> "${FLP}";
}

function get_mtu() {
	local interface_name="$1";
	local interface_mtu=$(/usr/sbin/ip link show "${interface_name}" | /usr/bin/egrep -o "mtu\s([1-9][0-9]{2,4})" | /usr/bin/awk '{print $NF}')
	dlog "Detected existing mtu of ${interface_mtu} on interface ${interface_name}"
	echo "${interface_mtu}"
}

function reachability_check() {
	local count=$1; local target="$2";
	[[ -f "${REACHABILITY_TEST_PCT_FILE}" ]] && rm -f "${REACHABILITY_TEST_PCT_FILE}" && dlog "Deleted ${REACHABILITY_TEST_PCT_FILE}"
	[[ -f "${REACHABILITY_TEST_MAC_FILE}" ]] && rm -f "${REACHABILITY_TEST_MAC_FILE}" && dlog "Deleted ${REACHABILITY_TEST_MAC_FILE}"
	dlog "Reachability test to ${target}"
	local reachability_result=$(/usr/bin/ping -q -c $count "${target}" | /usr/bin/egrep "packet loss")
	dlog "Reachability test output: ${reachability_result}"
	local pct=$(echo "$reachability_result" | /usr/bin/egrep -o "([0-9]{1,3}\%?) packet loss" | /usr/bin/awk '{print $NR}' | /usr/bin/egrep -o "^[0-9]{1,3}")
	echo "${pct}" > "${REACHABILITY_TEST_PCT_FILE}"
	/usr/sbin/arp -an | /usr/bin/egrep "\(${target}\)" | /usr/bin/awk '{print $4}' > "$REACHABILITY_TEST_MAC_FILE"
	if grep -q "incomplete" "${REACHABILITY_TEST_MAC_FILE}"; then
		dlog "Failed to resolve mac address for ${target}"
	else
		local target_mac=$(cat "${REACHABILITY_TEST_MAC_FILE}" | egrep -o "([0-9a-z]{2}\:?){6}");
		dlog "Resolved mac address ${target_mac} for ${target}"
	fi
	echo $pct
}
	

EXISTING_IF_MTU=$(get_mtu "${IFNAME}"); EXISTING_BR_MTU=$(get_mtu "${BRNAME}")
echo "Interface ${IFNAME} mtu: ${EXISTING_IF_MTU}"; echo "Interface ${BRNAME} mtu: ${EXISTING_BR_MTU}"
if [[ "${EXISTING_IF_MTU}" == "${MTU}" && "${EXISTING_BR_MTU}" == "${MTU}" ]]; then
	LOGMSG="MTU has already been configured on this host. Exiting."; dlog "${LOGMSG}"; echo "${LOGMSG}"; exit 0;
fi


LOGMSG="Configuring interfaces with ${MTU} mtu"; dlog "$LOGMSG"; echo "$LOGMSG";
/usr/sbin/ip link set "${IFNAME}" mtu "${MTU}" \
	&& /usr/sbin/ip link set "${BRNAME}" mtu "${MTU}" \
	&& dlog "Configured mtu of ${MTU} on interfaces: ${IFNAME}, ${BRNAME}"

LOGMSG="Verifying interface mtu updated to value ${MTU}"; dlog "$LOGMSG"; echo "$LOGMSG";

NEW_IF_MTU=$(get_mtu "${IFNAME}"); NEW_BR_MTU=$(get_mtu "${BRNAME}")
if [[ "${NEW_IF_MTU}" == "${MTU}" ]]; then
	LOGMSG="Verified interface ${IFNAME} mtu: ${NEW_IF_MTU}"; 
else
	LOGMSG="Error: Interface ${IFNAME} mtu is ${NEW_IF_MTU}"; 
fi
dlog "${LOGMSG}"; echo "${LOGMSG}";

if [[ "${NEW_BR_MTU}" == "${MTU}" ]]; then
	LOGMSG="Verified interface ${BRNAME} mtu: ${NEW_BR_MTU}"; 
else
	LOGMSG="Error: Interface ${BRNAME} mtu is ${NEW_BR_MTU}"; 
fi
dlog "${LOGMSG}"; echo "${LOGMSG}";


for item in "1" "2" "3" "4"; do
	sleep "${WAIT_TIME}"; LOSS_PCT=$(reachability_check $REACHABILITY_TEST_COUNT "$REACHABILITY_TEST_ADDR");
	LOGMSG="Packet loss to target node: ${LOSS_PCT}"; dlog "$LOGMSG"; echo "$LOGMSG";
	if [[ "${LOSS_PCT}" == "0" ]]; then
		LOGMSG="Connectivity confirmed ok. Exiting"; dlog "$LOGMSG"; echo "$LOGMSG"; break;
	else
		if [[ "${item}" == "4" ]]; then
			LOGMSG="Lost connectivity with ${REACHABILITY_TEST_ADDR} when mtu configured to ${MTU}. Restoring previous configuration"; dlog "$LOGMSG"; echo "$LOGMSG";
			/usr/sbin/ip link set "${BRNAME}" mtu "${EXISTING_BR_MTU}"; /usr/sbin/ip link set "${IFNAME}" mtu "${EXISTING_IF_MTU}";
			sleep "${WAIT_TIME}"; NEW_LOSS_PCT=$(reachability_check $REACHABILITY_TEST_COUNT "$REACHABILITY_TEST_ADDR");
			if [[ "${LOSS_PCT}" != "0" ]]; then
				LOGMSG="Reachability check failed after mtu restore. Rebooting in 20 seconds"; dlog "$LOGMSG"; echo "$LOGMSG";
				sleep 20 && reboot;
			fi
		fi
	fi
done

exit 0