more ways to configure bonding

*Setting up Network Bonding*

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1. Alias The Bonding Module And Set Module Options

The module options should be on a separate line from the alias.

RHEL3: This should go in /etc/modules.conf

RHEL4, RHEL5: This should go in /etc/modprobe.conf

Quick explanation:

mode=1 - specifies failover

miimon=100 - specifies MII link monitoring frequency of 100ms

alias bond0 bonding

options bond0 mode=1 miimon=100

2. Master Interface Configuration

Create /etc/sysconfig/network-scripts/ifcfg-bond0:

DEVICE=bond0

BOOTPROTO=none

ONBOOT=yes

IPADDR=<server's IP address>

NETMASK=<server's netmask>

USERCTL=no

3. Slave Interface Configuration

Change /etc/sysconfig/network-scripts/ifcfg-eth0 and ifcfg-eth1 to look like this:

DEVICE=eth<N>

BOOTPROTO=none

ONBOOT=yes

MASTER=bond0

SLAVE=yes

USERCTL=no

4. Static Gateway Routes (RHEL3 Only)

NB. This is not necessary on RHEL4 and RHEL5. It may still be necessary on RHEL3 - this is currently untested. Add the following lines to /etc/sysconfig/static-routes:

bond0 v <server's IP address>

bond0 v default gw <gateway IP>

5. Change The Gateway Device

Edit the GATEWAYDEV field in /etc/sysconfig/network to 'bond0' rather than 'eth0'.

6. MAC Addresses

RHEL3, RHEL4: Make sure there is not a 'HWADDR' field in ifcfg-eth0 or ifcfg-eth1. These confuse the bonding module.

RHEL5: Make sure there is a 'HWADDR' field in ifcfg-eth0 and ifcfg-eth1 (and ifcfg-eth2 for MBU). This is necessary to avoid the interfaces flipping on reboot.

Checking for entries:

grep -i hwaddr /etc/sysconfig/network-scripts/ifcfg-eth[0-9]

Adding entries:

for i in eth0 eth1 eth2; do echo -n 'HWADDR=' >> /etc/sysconfig/network-scripts/ifcfg-$i; ifconfig $i\

| awk '/HWaddr/{print $NF}' >> /etc/sysconfig/network-scripts/ifcfg-$i; done

Adding entries if bonding is already in place (the bonding module overrides the MAC address of eth1, so we need to make sure we get the right address):

for i in eth0 eth1; do echo -n 'HWADDR=' >> /etc/sysconfig/network-scripts/ifcfg-$i; grep -A3 $i /proc/net/bonding/bond0\

| awk '/Permanent/{print $NF}' >> /etc/sysconfig/network-scripts/ifcfg-$i; done

7. Restart Networking

Restarting networking will load the module automagically, there's no need to worry about this separately.

service network restart

8. Test!

Use the one-liner below to check that the server can ping it's gateway over each NIC individually (this script is split onto three lines deliberately). If possible, reboot the machine to verify that the settings remain static.

ifenslave -c bond0 eth1 && ping -c5 `route -n | awk '/^0.0.0.0/{print $2}'`;\

ifenslave -c bond0 eth0 && ping -c5 `route -n | awk '/^0.0.0.0/{print $2}'`;\

tail -25 /var/log/messages | grep bonding && cat /proc/net/bonding/bond*