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rated 0 times [  0] [ 0]  / answers: 1 / hits: 29162  / 2 Years ago, fri, july 8, 2022, 12:24:29

I know, that I can assign static IP manually, using /etc/network/interfaces.



I also know, that I can read the MAC address of the LXC container (e.g. by looking for lxc.network.hwaddr entry in /var/lib/lxc/<container-name>/config and assign the IP based using entries dhcp-host=<mac-addr>,10.0.3.3 in /etc/dnsmasq.d/<some file>.



In the file /etc/default/lxc-net I read 



# Uncomment the next line if you'd like to use a conf-file for the lxcbr0

# dnsmasq.  For instance, you can use 'dhcp-host=mail1,10.0.3.100' to have

# container 'mail1' always get ip address 10.0.3.100.

#LXC_DHCP_CONFILE=/etc/lxc/dnsmasq.conf


That would suit my needs; unfortunately doing so has no effect.


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 Answers
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This solution works by patching the lxc upstart scripts. It does split the complex task of bringing the lxcbr0 bridge up and starting a dnsmasq into two separate jobs. Now you don't need to restart the whole lxc-net bridge to just reload the dnsmasq - reloading the sudo service restart lxc-dnsmasq is sufficient and does not require shutting down the bridge.




  1. Stop the lxc-net service sudo service lxc-net stop and make sure there is no lxcbr0 (or equivalent) bridge up.

  2. Replace the contents of the /etc/init/lxc-net.conf with the following contents:



.



description "lxc network"

author "Serge Hallyn <[email protected]>"



start on starting lxc

stop on stopped lxc



env USE_LXC_BRIDGE="true"

env LXC_BRIDGE="lxcbr0"

env LXC_ADDR="10.0.3.1"

env LXC_NETMASK="255.255.255.0"

env LXC_NETWORK="10.0.3.0/24"

env varrun="/run/lxc"

env LXC_DOMAIN=""



pre-start script

    [ -f /etc/default/lxc ] && . /etc/default/lxc



    [ "x$USE_LXC_BRIDGE" = "xtrue" ] || { stop; exit 0; }



    use_iptables_lock="-w"

    iptables -w -L -n > /dev/null 2>&1 || use_iptables_lock=""

    cleanup() {

        # dnsmasq failed to start, clean up the bridge

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT

        iptables $use_iptables_lock -D FORWARD -i ${LXC_BRIDGE} -j ACCEPT

        iptables $use_iptables_lock -D FORWARD -o ${LXC_BRIDGE} -j ACCEPT

        iptables $use_iptables_lock -t nat -D POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE || true

        iptables $use_iptables_lock -t mangle -D POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill

        ifconfig ${LXC_BRIDGE} down || true

        brctl delbr ${LXC_BRIDGE} || true

    }

    if [ -d /sys/class/net/${LXC_BRIDGE} ]; then

        if [ ! -f ${varrun}/network_up ]; then

            # bridge exists, but we didn't start it

            stop;

        fi

        exit 0;

    fi



    # set up the lxc network

    brctl addbr ${LXC_BRIDGE} || { echo "Missing bridge support in kernel"; stop; exit 0; }

    echo 1 > /proc/sys/net/ipv4/ip_forward

    mkdir -p ${varrun}

    ifconfig ${LXC_BRIDGE} ${LXC_ADDR} netmask ${LXC_NETMASK} up

    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT

    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT

    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT

    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT

    iptables $use_iptables_lock -I FORWARD -i ${LXC_BRIDGE} -j ACCEPT

    iptables $use_iptables_lock -I FORWARD -o ${LXC_BRIDGE} -j ACCEPT

    iptables $use_iptables_lock -t nat -A POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE

    iptables $use_iptables_lock -t mangle -A POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill



    touch ${varrun}/network_up

end script



post-stop script

    [ -f /etc/default/lxc ] && . /etc/default/lxc

    [ -f "${varrun}/network_up" ] || exit 0;

    # if $LXC_BRIDGE has attached interfaces, don't shut it down

    ls /sys/class/net/${LXC_BRIDGE}/brif/* > /dev/null 2>&1 && exit 0;



    if [ -d /sys/class/net/${LXC_BRIDGE} ]; then

        use_iptables_lock="-w"

        iptables -w -L -n > /dev/null 2>&1 || use_iptables_lock=""

        ifconfig ${LXC_BRIDGE} down

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT

        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT

        iptables $use_iptables_lock -D FORWARD -i ${LXC_BRIDGE} -j ACCEPT

        iptables $use_iptables_lock -D FORWARD -o ${LXC_BRIDGE} -j ACCEPT

        iptables $use_iptables_lock -t nat -D POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE || true

        iptables $use_iptables_lock -t mangle -D POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill

        pid=`cat ${varrun}/dnsmasq.pid 2>/dev/null` && kill -9 $pid || true

        rm -f ${varrun}/dnsmasq.pid

        brctl delbr ${LXC_BRIDGE}

    fi

    rm -f ${varrun}/network_up

end script



  1. Add another file, /etc/init/lxc-dnsmasq with the following contents:



.



description "lxc dnsmasq service"

author "Adam Ryczkowski, ispired by Serge Hallyn <[email protected]>"



expect fork



start on started lxc-net

stop on stopped lxc-net



env USE_LXC_BRIDGE="true"

env LXC_BRIDGE="lxcbr0"

env LXC_ADDR="10.0.3.1"

env LXC_NETMASK="255.255.255.0"

env LXC_NETWORK="10.0.3.0/24"

env LXC_DHCP_RANGE="10.0.3.2,10.0.3.254"

env LXC_DHCP_MAX="253"

env LXC_DHCP_CONFILE=""

env varrun="/run/lxc-dnsmasq"

env LXC_DOMAIN=""



pre-start script

    [ -f /etc/default/lxc ] && . /etc/default/lxc



    [ "x$USE_LXC_BRIDGE" = "xtrue" ] || { stop; exit 0; }



    if [ ! -d ${varrun} ]; then

        mkdir -p ${varrun}

    fi

    opts="$LXC_DOMAIN_ARG -u lxc-dnsmasq --strict-order --bind-interfaces --pid-file=${varrun}/dnsmasq.pid --conf-file=${LXC_DHCP_CONFILE} --listen-address ${LXC_ADDR} --dhcp-range ${LXC_DHCP_RANGE} --dhcp-lease-max=${LXC_DHCP_MAX} --dhcp-no-override --except-interface=lo --interface=${LXC_BRIDGE} --dhcp-leasefile=/var/lib/misc/dnsmasq2.${LXC_BRIDGE}.leases --dhcp-authoritative --keep-in-foreground"



    /usr/sbin/dnsmasq $opts &



end script



post-stop script

    if [ -f ${varrun}/dnsmasq.pid ]; then

        PID=`cat ${varrun}/dnsmasq.pid`

        kill $PID

    fi

end script

[#26064] Friday, July 8, 2022, 2 Years  [reply] [flag answer]
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