{{Legacy}} This article describes how to assign public IPs to VEs containers running on OVZ Hardware Nodes in case you have a following network topology: 

This configuration was tested on a RHEL5 OpenVZ Hardware Node and a container based on a Fedora Core 5 template.Other host OSs and templates might require some configuration changes, please add corresponding OS specific changes if you've faced any. This article assumes the presence of 'brctl', 'ip' and 'ifconfig' utils. You may need to install missing packages like 'bridge-utils'/'iproute'/'net-tools' or others which contain those utilities. This article assumes you have already [[Quick installation|installed OpenVZ]], prepared the [[OS template cache]](s) and have [[Basic_operations_in_OpenVZ_environment|VEcontainer(s) created]]. If not, follow the links to perform the steps needed.{{Note|don't assign an IP after VE container creation.}}<br>== (1) An OVZ Hardware Node has the only one ethernet Ethernet interface ==

=== <u>Hardware Node configuration</u> === {{Warning|if you are '''configuring''' the node '''remotely''' you '''must''' prepare a '''script''' with the below commands and run it in background with the redirected output or you'll '''lose the access''' to the Node.}}

<pre> [HN]# brctl addbr br0</pre>

<pre> [HN]# ifconfig eth0 0</pre>

<pre> [HN]# brctl addif br0 eth0</pre>

<pre> [HN]# ifconfig br0 10.0.0.2/24</pre>

<pre> [HN]# ip route add default via 10.0.0.1 dev br0</pre>

<pre> [HN]# /tmp/br_add >/dev/null 2>&1 &</pre><br>=== <u>VE configuration</u> ===

===Container configuration = Start a VE ====<pre>[HN]# vzctl start 101</pre>

==== Add Start a [[Virtual_Ethernet_device|veth interface]] to the VE container ====<pre> [HN]# vzctl set start 101 --netif_add eth0 –save</pre>

==== Add a [[Virtual_Ethernet_device|veth interface]] to the container ==== [HN]# vzctl set 101 --netif_add eth0 --save ==== Set up an IP to the newly created VEcontainer's veth interface ====<pre> [HN]# vzctl exec 101 ifconfig eth0 85.86.87.194195/26</pre>

==== Add the container's veth interface to the bridge ==== [HN]# brctl addif br0 veth101.0 {{Note|There will be a delay of about 15 seconds(default for 2.6.18 kernel) while the bridge software runs STP to detect loops and transitions the veth interface to the forwarding state.<!-- /sys/class/net/$BR_NAME/bridge/forward_delay in SEC*USER_HZ -->}} ==== Set up the default route for the VE container ====<pre> [HN]# vzctl exec 101 ip route change add default via 85.86.87.192 193 dev eth0</pre>

==== (Optional) Add CT↔HN routes ====The above configuration provides the VEfollowing connections:* CT X ↔ CT Y (where CT X and CT Y can locate on any OVZ HN)* CT ↔ Internet Note that * The accessability of the CT from the HN depends on the local gateway providing NAT (probably - yes) * The accessability of the HN from the CT depends on the ISP gateway being aware of the local network (probably not) So to provide CT ↔ HN accessibility despite the gateways' configuration you can add the following routes:  [HN]# ip route add 85.86.87.195 dev br0 [HN]# vzctl exec 101 ip route add 10.0.0.2 dev eth0 === Resulting OpenVZ Node configuration ===[[Image:PrivateIPs_fig2.gif|Resulting OpenVZ Node configuration]] === Making the configuration persistent === ==== Set up a bridge on a HN ====This can be done by configuring the <code>ifcfg-*</code> files located in <code>/etc/sysconfig/network-scripts/</code>. Assuming you had a configuration file (e.g. <code>ifcfg-eth0</code>) like:<pre>DEVICE=eth0ONBOOT=yesIPADDR=10.0.0.2NETMASK=255.255.255.0GATEWAY=10.0.0.1</pre> To automatically create bridge <code>br0</code> you can create <code>ifcfg-br0</code>:<pre>DEVICE=br0TYPE=BridgeONBOOT=yesIPADDR=10.0.0.2NETMASK=255.255.255.0GATEWAY=10.0.0.1</pre> and edit <code>ifcfg-eth0</code> to add the <code>eth0</code> interface into the bridge <code>br0</code>:<pre>DEVICE=eth0ONBOOT=yesBRIDGE=br0</pre> ==== Edit the container's veth interface configuration ====Add these parameters to the <code>/etc/vz/conf/$CTID.conf</code> file which will be used during the network configuration:* Add <code>VETH_IP_ADDRESS="IP/MASK"</code> (a container can have multiple IPs separated by spaces)* Add <code>VE_DEFAULT_GATEWAY="CT DEFAULT GATEWAY"</code>* Add <code>BRIDGEDEV="BRIDGE NAME"</code> (a bridge name to which the container veth interface should be added) An example:<pre># Network customization sectionVETH_IP_ADDRESS="85.86.87.195/26"VE_DEFAULT_GATEWAY="85.86.87.193"BRIDGEDEV="br0"</pre> ==== Create a custom network configuration script ====which should be called each time a container is started (e.g. <code>/usr/sbin/vznetcfg.custom</code>):<pre>#!/bin/bash# /usr/sbin/vznetcfg.custom# a script to bring up bridged network interfaces (veth's) in a container GLOBALCONFIGFILE=/etc/vz/vz.confCTCONFIGFILE=/etc/vz/conf/$VEID.confvzctl=/usr/sbin/vzctlbrctl=/usr/sbin/brctlip=/sbin/ipifconfig=/sbin/ifconfig. $GLOBALCONFIGFILE. $CTCONFIGFILE NETIF_OPTIONS=`echo $NETIF | sed 's/,/\n/g'`for str in $NETIF_OPTIONS; do \ # getting 'ifname' parameter value if echo "$str" | grep -o "^ifname=" ; then # remove the parameter name from the string (along with '=') CTIFNAME=${str#*=}; fi # getting 'host_ifname' parameter value if echo "$str" | grep -o "^host_ifname=" ; then # remove the parameter name from the string (along with '=') VZHOSTIF=${str#*=}; fidone if [ ! -n "$VETH_IP_ADDRESS" ]; then echo "According to $CONFIGFILE CT$VEID has no veth IPs configured." exit 1fi if [ ! -n "$VZHOSTIF" ]; then echo "According to $CONFIGFILE CT$VEID has no veth interface configured." exit 1fi if [ ! -n "$CTIFNAME" ]; then echo "Corrupted $CONFIGFILE: no 'ifname' defined for host_ifname $VZHOSTIF." exit 1fi echo "Initializing interface $VZHOSTIF for CT$VEID."$ifconfig $VZHOSTIF 0 CTROUTEDEV=$VZHOSTIF if [HN-n "$BRIDGEDEV" ]# ; then echo "Adding interface $VZHOSTIF to the bridge $BRIDGEDEV." CTROUTEDEV=$BRIDGEDEV $brctl addif br0 veth101$BRIDGEDEV $VZHOSTIFfi # Up the interface $CTIFNAME link in CT$VEID$vzctl exec $VEID $ip link set $CTIFNAME up for IP in $VETH_IP_ADDRESS; do echo "Adding an IP $IP to the $CTIFNAME for CT$VEID." $vzctl exec $VEID $ip address add $IP dev $CTIFNAME  # removing the netmask IP_STRIP=${IP%%/*};  echo "Adding a route from CT0 to CT$VEID using $IP_STRIP." $ip route add $IP_STRIP dev $CTROUTEDEVdone if [ -n "$CT0_IP" ]; then echo "Adding a route from CT$VEID to CT0." $vzctl exec $VEID $ip route add $CT0_IP dev $CTIFNAMEfi if [ -n "$VE_DEFAULT_GATEWAY" ]; then echo "Setting $VE_DEFAULT_GATEWAY as a default gateway for CT$VEID." $vzctl exec $VEID \ $ip route add default via $VE_DEFAULT_GATEWAY dev $CTIFNAMEfi exit 0</pre><p><small>Note: this script can be easily extended to work for multiple triples &lt;bridge, ip address, veth device&gt;, see http://sysadmin-ivanov.blogspot.com/2008/02/2-veth-with-2-bridges-on-openvz-at.html </small></p> ==== Make the script to be run on a container start ====In order to run above script on a container start create the file<code>/etc/vz/vznet.conf</code> with the following contents:  EXTERNAL_SCRIPT="/usr/sbin/vznetcfg.custom" {{Note|<code>/usr/sbin/vznetcfg.custom</code> should be executable (chmod +x /usr/sbin/vznetcfg.custom)}} {{Note|When CT is stoped there are HW → CT route(s) still present in route table. We can use On-umount script for solve this.}} ==== Create On-umount script for remove HW → CT route(s) ====which should be called each time a container with VEID (<code>/etc/vz/conf/$VEID.umount</code>), or any container (<code>/etc/vz/conf/vps.umount</code>) is stopped.

VE X <#!/bin/bash# /etc/vz/conf/$VEID.umount or /etc/vz/conf/vps.umount# a script to remove routes to container with veth-> VE Y (where VE X and VE Y can locate on any OVZ HN)bridge from bridge  CTCONFIGFILE=/etc/vz/conf/$VEID.confip=/sbin/ip. $CTCONFIGFILE VE <if [ ! -> Internetn "$VETH_IP_ADDRESS" ]; thenHN exit 0fi if [ ! -> VEn "$BRIDGEDEV" ]; then exit 0fi for IP in $VETH_IP_ADDRESS; do # removing the netmask IP_STRIP=${IP%%/*}; echo "Remove a route from CT0 to CT$VEID using $IP_STRIP." $ip route del $IP_STRIP dev $BRIDGEDEVdone exit 0

If you really need {{Note|The script should be executable (chmod +x /etc/vz/conf/vps.umount)}} ==== Setting the route CT → HN ====To set up a VE route from the CT to have an access the HN, the custom script has to the get a HNIP (sthe $CT0_IP variable in the script) add . There are several ways to specify it: # Add an additional route rule:entry CT0_IP="CT0 IP" to the <code>$VEID.conf</code># Add an entry CT0_IP="CT0 IP" to the <precode>[/etc/vz/vz.conf</code> (the global configuration config file)# Implement some smart algorithm to determine the CT0 IP right in the custom network configuration script Each variant has its pros and cons, nevertheless for HN]# vzctl exec 101 ip route add static IP configuration variant 2 seems to be acceptable (and the most simple). == An OpenVZ Hardware Node has two Ethernet interfaces ==Assuming you have 2 interfaces eth0 and eth1 and want to separate local traffic (10.0.0.0/24 dev ) from external traffic.Let's assign eth0</pre>for the external traffic and eth1 for the local one. If there is no need to make the container accessible from the HN and vice versa, it's enough to replace 'br0' with 'eth1' in the following steps of the above configuration:* Hardware Node configuration → [[Using_private_IPs_for_Hardware_Nodes#Assign_the_IP_to_the_bridge|Assign the IP to the bridge]]* Hardware Node configuration → [[Using_private_IPs_for_Hardware_Nodes#Resurrect_the_default_routing|Resurrect the default routing]]

=== <u>The resulted OVZ Node configuration</u> ===[[Image:PrivateIPs_fig2It is nesessary to set a local IP for 'br0' to ensure CT ↔ HN connection availability.gif|The resulted OVZ Node configuration]]

=== <u>Making the configuration persistent</u> (TODO) =Putting containers to different subnetworks ==A Nardware Node configuration can be done with help of ordinary initscripts configuration i suppose,<br>It's enough to set up the correct $VETH_IP_ADDRESS and $VE_DEFAULT_GATEWAY values in the while VEs configuration will require creating additional script based on [[Virtual_Ethernet_deviceUsing_private_IPs_for_Hardware_Nodes#Making_a_veth-device_persistentEdit_the_container.27s_configuration|Making a veth-device persistentabove configuration]] scheme.<br>== (2) An OVZ Hardware Node has two ethernet interfaces (TODO) ==(assume eth0 and eth1)