Rate-limited backup to BackBlaze B2 with IPTables

b2_sync.sh

#!/bin/bash

# You can adjust the maximum throuhput limits (in mbits) here
BW_MAX_RATE=500mbit
BW_BURST_RATE=560mbit
IFACE=ens3

# Local/remote paths
B2_SOURCE_PATH="/local/path/to/backupdir"
B2_DEST_BUCKET="b2://your-bucket-name"
B2_DEST_BUCKET_PATH="/your-bucket-directory/"

# Configurable retention policies
B2_THREADS=4
B2_KEEPDAYS=30

B2_PID=`pidof -x b2`

# TODO: Control traffic from b2 proccess by putting it into a cgroup

if [ -z $B2_PID ]
then
        echo "[`date`]: Configuring network interface: iface($IFACE)..."

        echo "[`date`]: Removing any preexisting traffic shaping rules..."
        /sbin/tc qdisc del dev $IFACE root
        echo "[`date`]: Removing any preexisting mangle rules..."
        /usr/sbin/iptables -D OUTPUT -t mangle -p tcp --sport 443 -j MARK --set-mark 10

        echo "  + [`date`]: Enabling queuing..."
        /sbin/tc qdisc add dev $IFACE root handle 1:0 htb default 10
        echo "  + [`date`]: Applying traffic limits: iface($IFACE) net_max_rate($BW_MAX_RATE) net_burst_rate($BW_BURST_RATE)"
        /sbin/tc class add dev $IFACE parent 1:0 classid 1:10 htb rate $BW_MAX_RATE ceil $BW_BURST_RATE prio 0
        echo "[`date`]: Assigning queuing rule to qdisc..."
        /sbin/tc filter add dev $IFACE parent 1:0 prio 0 protocol ip handle 10 fw flowid 1:10
        echo "  + [`date`]: Installing mangle rule..."
        /usr/sbin/iptables -A OUTPUT -t mangle -p tcp --sport 443 -j MARK --set-mark 10

        echo "[`date`]: Starting b2 sync: threads($B2_THREADS) keepdays($B2_KEEPDAYS)..."

        cd $B2_SOURCE_PATH
        /usr/local/bin/b2 sync --threads $B2_THREADS --keepDays $B2_KEEPDAYS --replaceNewer $B2_SOURCE_PATH $B2_DEST_BUCKET$B2_DEST_BUCKET_PATH
        B2_RETURN_STATUS=$?
        echo "[`date`]: Sync complete, b2 client exiting with status b2_return_status($B2_RETURN_STATUS)"

        echo "[`date`]: Deconfiguring network interface: iface($IFACE)..."
        echo "[`date`]: Removing traffic shaping rules..."
        /sbin/tc qdisc del dev $IFACE root
        echo "[`date`]: Removing mangle rules..."
        /usr/sbin/iptables -D OUTPUT -t mangle -p tcp --sport 443 -j MARK --set-mark 10

        exit $B2_RETURN_STATUS
fi

# Terminate early- last b2 sync job is still running
echo "[`date`]: DYING - A b2 sync job is already running!"
exit 1