LACP-Teaming on CentOS 7 / RHEL 7

What is teaming?
Teaming or LACP (802.3ad) is a technique used to bond together multiple interfaces to achieve higher combined bandwith. NOTE: every clients speed can only be as high as the single link speed of one of the members. That means, if the interfaces I use in the bond have 1 Gigabit, every client will only have a maximum speed of 1 Gigabit. The advantage of teaming is, that it can handle multiple connections with 1 Gigabit. How many connections depends on the amount of your network cards.

I'm using 2 network cards for this team on my server. That means I can handle 2 Gigabit connections at full rate on my server provided the rest of the hardware can deliver that speed.

There also exists 'Bonding' in the Linux world. They both do the same in theory but  for a detailed comparison check out this article about teaming in RHEL7.

To create a teaming-interface, we will first have to remove all the interface configurations we've done on the (soon to be) slave-interfaces for our team. I've edited the ifcfg-files to look like the following:

The first interface:

 [archy@server ~]$ sudo cat /etc/sysconfig/network-scripts/ifcfg-eth0  
 TYPE=Ethernet  
 BOOTPROTO=none  
 DEFROUTE=yes  
 PEERDNS=yes  
 PEERROUTES=yes  
 IPV4_FAILURE_FATAL=no  
 NAME=eth0  
 UUID=811289b3-8c1f-4f38-8885-21fa8aef107f  
 DEVICE=eth0  
 ONBOOT=no  

The second interface:

 [archy@server ~]$ sudo cat /etc/sysconfig/network-scripts/ifcfg-eth1  
 TYPE=Ethernet  
 BOOTPROTO=none  
 DEFROUTE=yes  
 PEERDNS=yes  
 PEERROUTES=yes  
 IPV4_FAILURE_FATAL=no  
 NAME=eth1  
 UUID=811289b3-8c1f-4f38-8885-21fa8aef107f  
 DEVICE=eth1  
 ONBOOT=no  

The teaming-interface:

 [archy@server ~]$ sudo cat /etc/sysconfig/network-scripts/ifcfg-team0  
 DEVICE=team0  
 PROXY_METHOD=none  
 BROWSER_ONLY=no  
 BOOTPROTO=none  
 IPADDR=172.31.0.250  
 PREFIX=24  
 GATEWAY=172.31.0.254  
 DNS1=127.0.0.1  
 DOMAIN="archyslife.lan"  
 DEFROUTE=yes  
 IPV4_FAILURE_FATAL=no  
 IPV6INIT=yes  
 NAME=team0  
 UUID=993942fd-9aee-4544-9ad7-8bedcd7beb0b  
 ONBOOT=yes  
 DEVICETYPE=Team  
 TEAM_CONFIG="{\"runner\": {\"name\": \"lacp\", \"active\": true, \"fast_rate\": true, \"tx_hash\": [\"eth\", \"ipv4\", \"ipv6\"]},\"link_watch\":    {\"name\": \"ethtool\"}}"  

Now it's time to restart the network.service to activate the changes

 [archy@server ~]$ sudo systemctl restart network.service  

The state of the teaming can be checked using the teamd-tools:

 [archy@server ~]$ sudo teamdctl team0 state  
 setup:  
  runner: lacp  
 ports:  
  eth0  
   link watches:  
    link summary: up  
    instance[link_watch_0]:  
     name: ethtool  
     link: up  
     down count: 0  
   runner:  
    aggregator ID: 3, Selected  
    selected: yes  
    state: current  
  eth1  
   link watches:  
    link summary: up  
    instance[link_watch_0]:  
     name: ethtool  
     link: up  
     down count: 0  
   runner:  
    aggregator ID: 3, Selected  
    selected: yes  
    state: current  
 runner:  
  active: yes  
  fast rate: yes  
 [archy@server ~]$ sudo teamnl team0 ports  
  3: eth0: up 1000Mbit FD   
  2: eth1: up 1000Mbit FD    

The easiest way to configure is to use the nmcli or nmtui tool provided by the NetworkManager-package.

 [archy@server ~]$ sudo nmcli connection add type team con-name team0 ifname team0 config '{"runner": {"name": "lacp"}}'   
 [archy@server ~]$ sudo nmcli connection add type team-slave con-name team0-eth0 ifname eth0 master team0  
 [archy@server ~]$ sudo nmcli connection add type team-slave con-name team0-eth1 ifname eth1 master team0  

Usually the nmcli should have brought up the connection(s) automatically, but I usually restart the network.service anyway,. Just to make sure.

 [archy@server ~]$ sudo systemctl restart network.service  

The state of the teaming can be checked using the teamd-tools:

 [archy@server ~]$ sudo teamdctl team0 state  
 setup:  
  runner: lacp  
 ports:  
  eth0  
   link watches:  
    link summary: up  
    instance[link_watch_0]:  
     name: ethtool  
     link: up  
     down count: 0  
   runner:  
    aggregator ID: 3, Selected  
    selected: yes  
    state: current  
  eth1  
   link watches:  
    link summary: up  
    instance[link_watch_0]:  
     name: ethtool  
     link: up  
     down count: 0  
   runner:  
    aggregator ID: 3, Selected  
    selected: yes  
    state: current  
 runner:  
  active: yes  
  fast rate: yes  
 [archy@server ~]$ sudo teamnl team0 ports  
  3: eth0: up 1000Mbit FD   
  2: eth1: up 1000Mbit FD   

Feel free to comment and / or suggest a topic.