E.2. Configuring Routes and Default Routes
There are two ways a host has default routes set. If the interface is using DHCP and the DHCP server offers a gateway address, the system uses a default route for that gateway. Otherwise, you can set a default route on an interface with a static IP.
Although the Linux kernel supports multiple default gateways, it only uses the one with the lowest metric. If there are multiple DHCP interfaces, this can result in an unpredictable default gateway. In this case, it is recommended to set
defroute=no for interfaces other than the one using the default route.
For example, you might want a DHCP interface (
nic3) to be the default route. Use the following YAML to disable the default route on another DHCP interface (nic2):
# No default route on this DHCP interface - type: interface name: nic2 use_dhcp: true defroute: false # Instead use this DHCP interface as the default route - type: interface name: nic3 use_dhcp: true
Note
The
defroute parameter only applies to routes obtained through DHCP.
To set a static route on an interface with a static IP, specify a route to the subnet. For example, you can set a route to the 10.1.2.0/24 subnet through the gateway at 172.17.0.1 on the Internal API network:
- type: vlan
device: bond1
vlan_id: {get_param: InternalApiNetworkVlanID}
addresses:
- ip_netmask: {get_param: InternalApiIpSubnet}
routes:
- ip_netmask: 10.1.2.0/24
next_hop: 172.17.0.1
