Open Virtual Network With firewalld¶
firewalld is a service that allows for easy administration of firewalls. OVN ships with a set of service files that can be used with firewalld to allow for remote connections to the northbound and southbound databases.
This guide will describe how you can use these files with your existing firewalld setup. Setup and administration of firewalld is outside the scope of this document.
If you have installed OVN from an RPM, then the service files for firewalld
will automatically be installed in
Installation from RPM includes installation from the yum or dnf package
If you have installed OVN from source, then from the top level source directory, issue the following commands to copy the firewalld service files:
$ cp rhel/usr_lib_firewalld_services_ovn-central-firewall-service.xml \ /etc/firewalld/services/ $ cp rhel/usr_lib_firewalld_services_ovn-host-firewall-service.xml \ /etc/firewalld/services/
Assuming you are already running firewalld, you can issue the following commands to enable the OVN services.
On the central server (the one running
ovn-northd), issue the following:
$ firewall-cmd --zone=public --add-service=ovn-central-firewall-service
This will open TCP ports 6641 and 6642, allowing for remote connections to the northbound and southbound databases.
On the OVN hosts (the ones running
ovn-controller), issue the following:
$ firewall-cmd --zone=public --add-service=ovn-host-firewall-service
This will open UDP port 6081, allowing for geneve traffic to flow between the controllers.
When installing the XML service files, you have the choice of copying them to
/usr/lib/firewalld/services. The former is
recommend since the latter can be overwritten if firewalld is upgraded.
The above commands assumed your underlay network interfaces are in the “public” firewalld zone. If your underlay network interfaces are in a separate zone, then adjust the above commands accordingly.
--permanent option may be passed to the above firewall-cmd invocations
in order for the services to be permanently added to the firewalld
configuration. This way it is not necessary to re-issue the commands each
time the firewalld service restarts.
The ovn-host-firewall-service only opens port 6081. This is because the default protocol for OVN tunnels is geneve. If you are using a different encapsulation protocol, you will need to modify the XML service file to open the appropriate port(s). For VXLAN, open port 4789. For STT, open port 7471.
The firewalld service files included with the OVS repo are meant as a convenience for firewalld users. All that the service files do is to open the common ports used by OVN. No additional security is provided. To ensure a more secure environment, it is a good idea to do the following
- Use tools such as iptables or nftables to restrict access to known hosts.
- Use SSL for all remote connections to OVN databases.
- Use role-based access control for connections to the OVN southbound database.