[Yandex Cloud documentation](../../../index.md) > [Yandex BareMetal](../../index.md) > [Step-by-step guides](../index.md) > Servers > Configuring the MC-LAG aggregation group # Configuring the MC-LAG aggregation group Servers with [MC-LAG](../../concepts/mc-lag.md) support use two network adapters to simultaneously connect to each of the networks ([public](../../concepts/public-network.md) and [private](../../concepts/private-network.md)). To ensure fault tolerance, each of the network interface pairs connected to the networks must form an _aggregation group_ on the server side. For more information, see [Configuring aggregation groups and network interfaces](../../concepts/mc-lag.md#additional-setup). {% note info %} When setting up aggregation groups, do not connect to the server via the network interface you are going to include in a group: the connection with be lost when you create the group. The [KVM console](server-kvm.md) is the most reliable way to configure MC-LAG groups. {% endnote %} Currently, you can set up MC-LAG groups in Linux Ubuntu 20.04, 22.04, 24.04, and Debian 11. As an example, this guide uses a server with two pairs of network adapters with connection speed of 25 Gbps each. To set up a link aggregation group: {% list tabs group=operating_system %} - Ubuntu/Debian (Netplan) {#ubuntu} 1. Install `ethtool`: ```bash apt install ethtool ``` 1. Make sure the required network interfaces are installed in the system and active: ```bash ip link ``` Result: ```text ... 2: etx3: mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d6 brd ff:ff:ff:ff:ff:ff 3: etx4: mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d7 brd ff:ff:ff:ff:ff:ff 4: etx1: mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 58:a2:e1:ad:38:2a brd ff:ff:ff:ff:ff:ff 5: etx2: mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 58:a2:e1:ad:38:2b brd ff:ff:ff:ff:ff:ff ``` As you can see from the output, the server has four active network interfaces: * `etx3`: With the `b8:ce:f6:40:12:d6` MAC address. * `etx4`: With the `b8:ce:f6:40:12:d7` MAC address. * `etx1`: With the `58:a2:e1:ad:38:2a` MAC address. * `etx2`: With the `58:a2:e1:ad:38:2b` MAC address. 1. Find out which of the interfaces belong to the public network, and which to the private one: 1. In the [management console](https://console.yandex.cloud), select the [folder](../../../resource-manager/concepts/resources-hierarchy.md#folder) the server belongs to. 1. Go to **BareMetal** and select the server in the list of servers. On the page that opens, in the `MAC address` field under **Network interfaces**, you can see the MAC addresses of interfaces connected to the public and private networks, respectively. 1. Use the information obtained in the two previous steps to identify the server interface pairs connected to the public and private networks. In the example above, the pairs are as follows: **Public network**: * `etx3`: With the `b8:ce:f6:40:12:d6` MAC address. * `etx1`: With the `58:a2:e1:ad:38:2a` MAC address. **Private network**: * `etx4`: With the `b8:ce:f6:40:12:d7` MAC address. * `etx2`: With the `58:a2:e1:ad:38:2b` MAC address. 1. Find out the name of the [Netplan](https://netplan.io/) configuration file: ```bash ls /etc/netplan/ ``` Result: ```text 50-cloud-init.yaml ``` 1. Open the Netplan configuration file with a text editor. In this guide, we use [nano](https://en.wikipedia.org/wiki/GNU_nano): ```bash nano /etc/netplan/50-cloud-init.yaml ``` 1. Edit the Netplan configuration by adding aggregation groups (the `bonds` section): ```yaml network: bonds: bond1: dhcp4: true interfaces: - - macaddress: parameters: lacp-rate: fast mode: 802.3ad transmit-hash-policy: layer3+4 bond2: dhcp4: true interfaces: - - macaddress: parameters: lacp-rate: fast mode: 802.3ad transmit-hash-policy: layer3+4 ethernets: etx1: dhcp4: false match: macaddress: 58:a2:e1:ad:38:2a set-name: etx1 etx2: dhcp4: false match: macaddress: 58:a2:e1:ad:38:2b set-name: etx2 etx3: dhcp4: false match: macaddress: b8:ce:f6:40:12:d6 set-name: etx3 etx4: dhcp4: false match: macaddress: b8:ce:f6:40:12:d7 set-name: etx4 version: 2 ``` Where: * ``, ``: Names of the interfaces which belong to the public network, as you found out earlier. * ``: MAC address of an interface which belongs to the public network, as you found out earlier. * ``, ``: Names of the interfaces which belong to the private network, as you found out earlier. * ``: MAC address of an interface which belongs to the private network, as you found out earlier. {% note warning %} Note that [DHCP](../../concepts/dhcp.md) must be: * Enabled (`dhcp4: true`) for aggregation groups (the `bonds` section). * Disabled (`dhcp4: false`) for individual interfaces (the `ethernets` section). {% endnote %} {% cut "Netplan configuration example" %} ```yaml network: bonds: bond1: dhcp4: true interfaces: - etx3 - etx1 macaddress: b8:ce:f6:40:12:d6 parameters: lacp-rate: fast mode: 802.3ad transmit-hash-policy: layer3+4 bond2: dhcp4: true interfaces: - etx4 - etx2 macaddress: b8:ce:f6:40:12:d7 parameters: lacp-rate: fast mode: 802.3ad transmit-hash-policy: layer3+4 ethernets: etx1: dhcp4: false match: macaddress: 58:a2:e1:ad:38:2a set-name: etx1 etx2: dhcp4: false match: macaddress: 58:a2:e1:ad:38:2b set-name: etx2 etx3: dhcp4: false match: macaddress: b8:ce:f6:40:12:d6 set-name: etx3 etx4: dhcp4: false match: macaddress: b8:ce:f6:40:12:d7 set-name: etx4 version: 2 ``` {% endcut %} {% note info %} If there are [secondary private subnets](../../concepts/private-network.md#tagged-vlan-subnet) attached to the server, configure the server VLANs. For more information, see [Setting up a secondary private subnet with a tagged VLAN on a server](set-up-tagged-vlan.md). {% endnote %} 1. Apply the new Netplan configuration: ```bash netplan apply ``` 1. Make sure the list of network interfaces displays the aggregation groups: ```bash ip link ``` Result: ```text ... 2: etx3: mtu 1500 qdisc mq master bond1 state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d6 brd ff:ff:ff:ff:ff:ff 3: etx4: mtu 1500 qdisc mq master bond2 state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d7 brd ff:ff:ff:ff:ff:ff 4: etx1: mtu 1500 qdisc mq master bond1 state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d6 brd ff:ff:ff:ff:ff:ff 5: etx2: mtu 1500 qdisc mq master bond2 state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d7 brd ff:ff:ff:ff:ff:ff 6: bond1: mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d6 brd ff:ff:ff:ff:ff:ff 7: bond2: mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 link/ether b8:ce:f6:40:12:d7 brd ff:ff:ff:ff:ff:ff ``` As you can see from the output, the server now has two MC-LAG aggregation groups, `bond1` and `bond2`. {% note info %} If aggregation groups are inactive (`DOWN`), activate them: ```bash ip link set bond1 up ip link set bond2 up ``` {% endnote %} 1. View the information about the groups you created. As an example, let’s use the aggregation group connected to the public network: ```bash ethtool bond1 ``` Result: ``` Settings for bond1: Supported ports: [ ] Supported link modes: Not reported Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not reported Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 50000Mb/s Duplex: Full Port: Other PHYAD: 0 Transceiver: internal Auto-negotiation: off Link detected: yes ``` As you can see from the output, the connection speed for the `bond1` group is 50 Gbps. 1. Simulate an incident where a link in the `bond1` public network aggregation group fails. To do this, disable one of the group’s network interfaces: ```bash ip link set etx3 down ``` 1. View the group information again: ```bash ethtool bond1 ``` Result: ``` Settings for bond1: Supported ports: [ ] Supported link modes: Not reported Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not reported Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 25000Mb/s Duplex: Full Port: Other PHYAD: 0 Transceiver: internal Auto-negotiation: off Link detected: yes ``` As you can see from the output, the connection speed for the `bond1` group has been reduced to 25 Gbps, but the network connectivity has been maintained. To check this, [connect](../../../compute/operations/vm-connect/ssh.md) to the server over SSH. 1. Activate the interface you disabled earlier and make sure the aggregation group is running again at the maximum speed: ```bash ip link set etx3 up ethtool bond1 ``` Result: ```text Settings for bond1: Supported ports: [ ] Supported link modes: Not reported Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not reported Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 50000Mb/s Duplex: Full Port: Other PHYAD: 0 Transceiver: internal Auto-negotiation: off Link detected: yes ``` {% endlist %} #### See also {#see-also} * [Reserving a BareMetal network connection using MC-LAG](../../concepts/mc-lag.md) * [Network](../../concepts/network.md) * [Restrictions in BareMetal networks](../../concepts/network-restrictions.md)