Configuring Linux Policy Routing using Ansible
In this post, I’m going to talk about using Ansible to configure policy routing on Linux. If you’re not familiar with Linux policy routing, have a look at this post, and also review this post for one potential use case (I’m sure there are a number of other quite valuable use cases).
As you may recall from the policy routing introductory post, there are three steps involved in configuring policy routing:
- You must define the new routing table in
/etc/iproute2/rt_tables - You must add routes to the new routing tables
- You must define rules for when the new routing table is consulted
All three of these tasks can be handled via Ansible.
To address step #1, you can use Ansible’s “lineinfile” module to add a reference to the new routing table in /etc/iproute2/rt_tables. For example, consider this Ansible task:
- lineinfile: dest=/etc/iproute2/rt_tables line="200 eth1"
This snippet of Ansible code would add the line “200 eth1” to the end of the etc/iproute2/rt_tables file (if the line does not already exist). This takes care of task #1.
For tasks #2 and #3, you can use a Jinja2 template. Because the creation of the policy routing rule and the routing table entries can Continue reading
David Goeckeler is now GM of the Networking and Security Business Group at Cisco.
