Add support to configure policy based routing

Bug #1807297 reported by Giridhar Jayavelu on 2018-12-07
12
This bug affects 2 people
Affects Status Importance Assigned to Milestone
cloud-init
High
Unassigned

Bug Description

When there are multiple interfaces with their own default gateways, this could result in asymmetric routing. In order to solve this, policy based routing would have to be configured.

- There is already support to configure routes in cloud-init, but it misses ability to specify routing table.
- Need ability to create routing table entries in /etc/iproute2/rt_tables
- Configure routing table lookup for a given network.

Here is a sample configuration:
echo "100 eth0" >> /etc/iproute2/rt_tables
echo "101 eth1" >> /etc/iproute2/rt_tables

auto eth0
iface eth0 inet static
    address 10.172.142.37/24
    dns-nameservers 10.172.40.1
    gateway 10.172.142.253
    up ip rule add from 10.172.142.0/24 lookup eth0
    up ip route add 10.172.142.0/24 dev eth0 table eth0
    up ip route add default via 10.172.142.253 table eth0

auto eth1
iface eth1 inet static
    address 10.172.144.56/24
    dns-nameservers 10.172.40.1
    gateway 10.172.144.253
    up ip rule add from 10.172.144.0/24 lookup eth1
    up ip route add 10.172.144.0/24 dev eth1 table eth1
    up ip route add default via 10.172.144.253 table eth1

Ryan Harper (raharper) wrote :

Hi,

Thanks for filing the bug. This is a valid scenario.

Changed in cloud-init:
importance: Undecided → High
status: New → Triaged
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