Adding a bonding device
1. install ifenslave package:
core:~# aptitude install ifenslave Note: selecting "ifenslave-2.6" instead of the virtual package "ifenslave" The following NEW packages will be installed: ifenslave-2.6 0 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 18.4 kB of archives. After unpacking 143 kB will be used. Get:1 http://ftp.debian.org/debian/ squeeze/main ifenslave-2.6 amd64 1.1.0-17 [18.4 kB] Fetched 18.4 kB in 0s (63.1 kB/s) Selecting previously deselected package ifenslave-2.6. (Reading database ... 175297 files and directories currently installed.) Unpacking ifenslave-2.6 (from .../ifenslave-2.6_1.1.0-17_amd64.deb) ... Processing triggers for man-db ... Setting up ifenslave-2.6 (1.1.0-17) ... update-alternatives: using /sbin/ifenslave-2.6 to provide /sbin/ifenslave (ifenslave) in auto mode.
2. If you have the slave interface (in our example eth1 and eth2) already configured, remove their configuration from /etc/network/interfaces and add the following instead (in the same file):
auto bond0 iface bond0 inet static address 192.168.11.1 netmask 255.255.255.0 network 192.168.11.0 broadcast 192.168.11.255 slaves eth1 eth2 bond_mode active-backup bond_miimon 100 bond_downdelay 200 bond_updelay 200
3. Flush the ip configuration on eth1 and eth2:
core:~# ip address show dev eth1 3: eth1: <BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc pfifo_fast master bond0 state UNKNOWN qlen 1000 link/ether 00:22:b0:68:73:4d brd ff:ff:ff:ff:ff:ff inet 192.168.10.1/24 brd 192.168.10.255 scope global eth1 core:~# [color=green]ip address flush dev eth1[/color] core:~# ip address show dev eth1 3: eth1: <BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc pfifo_fast master bond0 state UNKNOWN qlen 1000 link/ether 00:22:b0:68:73:4d brd ff:ff:ff:ff:ff:ff core:~# ip address show dev eth2 4: eth2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP qlen 1000 link/ether 00:22:b0:68:73:4d brd ff:ff:ff:ff:ff:ff inet 192.168.69.1/24 brd 192.168.69.255 scope global eth2 core:~# [color=green]ip address flush dev eth2[/color] core:~# ip address show dev eth2 4: eth2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP qlen 1000 link/ether 00:22:b0:68:73:4d brd ff:ff:ff:ff:ff:ff
4. start the bond device (on my server samba was restarted automatically, it may not be the case on yours):
core:~# ifup bond0 Starting Samba daemons: nmbd smbd.
5. restart the networking:
core:~# /etc/init.d/networking restart done. core:~#
6. You should now have your bond device active:
core:~# ifconfig bond0 bond0 Link encap:Ethernet HWaddr 00:22:b0:68:73:4d inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0 UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 RX packets:2623 errors:0 dropped:0 overruns:0 frame:0 TX packets:81 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:415762 (406.0 KiB) TX bytes:14461 (14.1 KiB)
You can check the bonding interface status with the following commands:
core:~# cat /sys/class/net/bond0/bonding/mode active-backup 1
core:~# cat /proc/net/bonding/bond0 Ethernet Channel Bonding Driver: v3.5.0 (November 4, 2008) Bonding Mode: fault-tolerance (active-backup) Primary Slave: None Currently Active Slave: eth2 MII Status: up MII Polling Interval (ms): 100 Up Delay (ms): 200 Down Delay (ms): 200 Slave Interface: eth1 MII Status: down Link Failure Count: 0 Permanent HW addr: 00:22:00:89:03:00 Slave Interface: eth2 MII Status: up Link Failure Count: 0 Permanent HW addr: 00:24:00:70:A1:00
NOTE: if you have dhcpd server configured for one of the interfaces eth1 and eth2, do not forget to modify it and restart it also:
core:~# cat /etc/default/isc-dhcp-server | egrep -v "^$|^#" INTERFACES="bond0" core:~# /etc/init.d/isc-dhcp-server restart Stopping ISC DHCP server: dhcpd. Starting ISC DHCP server: dhcpd.
Regarding bond_mode in the point 1, I have opted for active-backup but there are other options too. Below you can read about all of them:
Mode 0 (balance-rr)
This mode transmits packets in a sequential order from the first available slave through the last. If two real interfaces are slaves in the bond and two packets arrive destined out of the bonded interface the first will be transmitted on the first slave and the second frame will be transmitted on the second slave. The third packet will be sent on the first and so on. This provides load balancing and fault tolerance.
Mode 1 (active-backup)
This mode places one of the interfaces into a backup state and will only make it active if the link is lost by the active interface. Only one slave in the bond is active at an instance of time. A different slave becomes active only when the active slave fails. This mode provides fault tolerance.
Mode 2 (balance-xor)
Transmits based on XOR formula. (Source MAC address is XOR’d with destination MAC address) modula slave count. This selects the same slave for each destination MAC address and provides load balancing and fault tolerance.
Mode 3 (broadcast)
This mode transmits everything on all slave interfaces. This mode is least used (only for specific purpose) and provides only fault tolerance.
Mode 4 (802.3ad)
This mode is known as Dynamic Link Aggregation mode. It creates aggregation groups that share the same speed and duplex settings. This mode requires a switch that supports IEEE 802.3ad Dynamic link.
Mode 5 (balance-tlb)
This is called as Adaptive transmit load balancing. The outgoing traffic is distributed according to the current load and queue on each slave interface. Incoming traffic is received by the current slave.
Mode 6 (balance-alb)
This is Adaptive load balancing mode. This includes balance-tlb + receive load balancing (rlb) for IPV4 traffic. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the server on their way out and overwrites the src hw address with the unique hw address of one of the slaves in the bond such that different clients use different hw addresses for the server.
Removing a bonding device
1. Remove the bond configuration from /etc/network/interfaces
2. Unconfigure the bonding device: echo "-bond0" > /sys/class/net/bonding_masters
3. Restart the networking.
root@candy:~# ifconfig bond0 bond0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 inet addr:192.168.69.12 Bcast:192.168.69.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:fe74:91af/64 Scope:Link UP BROADCAST MASTER MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) root@candy:~# ip addr flush dev bond0 root@candy:~# ifconfig bond0 bond0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 BROADCAST MASTER MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) root@candy:~# cat /sys/class/net/bonding_masters bond0 root@candy:~# echo "-bond0" > /sys/class/net/bonding_masters root@candy:~# ifconfig bond0 bond0: error fetching interface information: Device not found root@candy:~# rmmod bonding