rancherOS/docs/os/networking/interfaces/index.md

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title: Configuring Network Interfaces in RancherOS layout: os-default redirect_from:

• os/configuration/networking/ ---

Interfaces

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Using ros config, you can configure specific interfaces. Wildcard globbing is supported so eth* will match eth1 and eth2. The available options you can configure are address, gateway, mtu, and dhcp.

$ sudo ros config set rancher.network.interfaces.eth1.address 172.68.1.100/24
$ sudo ros config set rancher.network.interfaces.eth1.gateway 172.68.1.1
$ sudo ros config set rancher.network.interfaces.eth1.mtu 1500
$ sudo ros config set rancher.network.interfaces.eth1.dhcp false

If you wanted to configure the interfaces through the cloud config file, you'll need to place interface configurations within the rancher key.

#cloud-config
rancher:
  network:
    interfaces:
      eth1:
        address: 172.68.1.100/24
        gateway: 172.68.1.1
        mtu: 1500
        dhcp: false

Multiple NICs

If you want to configure one of multiple network interfaces, you can specify the MAC address of the interface you want to configure.

Using ros config, you can specify the MAC address of the NIC you want to configure as follows:

$ sudo ros config set rancher.network.interfaces.”mac=ea:34:71:66:90:12:01”.dhcp true

Alternatively, you can place the MAC address selection in your cloud config file as follows:

#cloud-config
rancher:
  network:
    interfaces:
      "mac=ea:34:71:66:90:12:01":
         dhcp: true

NIC bonding

You can aggregate several network links into one virtual link for redundancy and increased throughput. For example:

#cloud-config
rancher:
  network:
    interfaces:
      bond0:
        addresses:
        - 192.168.101.33/31
        - 10.88.23.129/31
        gateway: 192.168.101.32
        bond_opts:
          downdelay: "200"
          lacp_rate: "1"
          miimon: "100"
          mode: "4"
          updelay: "200"
          xmit_hash_policy: layer3+4
        post_up:
        - ip route add 10.0.0.0/8 via 10.88.23.128
      mac=0c:c4:d7:b2:14:d2:
        bond: bond0
      mac=0c:c4:d7:b2:14:d3:
        bond: bond0

In this example two physical NICs (with MACs 0c:c4:d7:b2:14:d2 and 0c:c4:d7:b2:14:d3) are aggregated into a virtual one bond0.

VLANS

In this example, you can create an interface eth0.100 which is tied to VLAN 100 and an interface foobar that will be tied to VLAN 200.

#cloud-config
rancher:
  network:
    interfaces:
      eth0:
        vlans: 100,200:foobar

Bridging

In this example, you can create a bridge interface.

#cloud-config
rancher:
  network:
    interfaces:
      br0:
        bridge: true
        dhcp: true
      eth0:
        bridge: br0

Run custom network configuration commands

You can configure pre and post network configuration commands to run in the network service container by adding pre_cmds and post_cmds array keys to rancher.network, or pre_up andpost_up keys for specific rancher.network.interfaces.

For example:

#cloud-config
write_files:
  - container: network
    path: /var/lib/iptables/rules.sh
    permissions: "0755"
    owner: root:root
    content: |
      #!/bin/bash
      set -ex
      echo $@ >> /var/log/net.log
      # the last line of the file needs to be a blank line or a comment
rancher:
  network:
    dns:
      nameservers:
        - 8.8.4.4
        - 4.2.2.3
    pre_cmds:
    - /var/lib/iptables/rules.sh pre_cmds
    post_cmds:
    - /var/lib/iptables/rules.sh post_cmds
    interfaces:
      lo:
        pre_up:
        - /var/lib/iptables/rules.sh pre_up lo
        post_up:
        - /var/lib/iptables/rules.sh post_up lo
      eth0:
        pre_up:
        - /var/lib/iptables/rules.sh pre_up eth0
        post_up:
        - /var/lib/iptables/rules.sh post_up eth0
      eth1:
        dhcp: true
        pre_up:
        - /var/lib/iptables/rules.sh pre_up eth1
        post_up:
        - /var/lib/iptables/rules.sh post_up eth1
      eth2:
        address: 192.168.3.13/16
        mtu: 1450
        pre_up:
        - /var/lib/iptables/rules.sh pre_up eth2
        post_up:
        - /var/lib/iptables/rules.sh post_up eth2