Contrail vRouter MAC Address - IP Address Learning and Bidirectional Forwarding and Detection Health Checking for Pods on Virtual Machines
In Contrail Networking Release 2011, the Contrail vRouter agent dynamically learns the MAC address-IP address binding of a pod deployed on a virtual machine (VM). This enables the vRouter agent to perform an efficient pod to pod communication in Contrail Networking.
In previous releases, the MAC address - IP address of a pod is assigned by OpenStack. Contrail Networking is unable to perform pod to pod communication as it does not have the reachability information of the pods hosted by the VMs.
Starting in Contrail Networking Release 21.3.1, a vRouter can learn multiple MAC-IP address bindings for a single MAC address when Dynamic Address Learning is enabled in a virtual network. In previous Contrail Networking releases, a vRouter could only learn a single MAC-IP address binding per MAC address.
The Contrail vRouter automatically learns multiple MAC-IP address bindings when a single MAC address is bound to multiple IP addresses and Dynamic Address Learning is enabled; no additional user configuration to support learning of the MAC-IP address bindings is needed or possible. Cloud-networking environments using Openstack orchestration and Contrail Networking can seamlessly support the learning of IPVLAN MAC address-IP address bindings over VM interfaces as a result of the vRouter’s ability to learn multiple MAC-IP address bindings to a single MAC address.
In the Contrail Command user interface (UI), the Dynamic Address Learning checkbox must be enabled while creating a virtual network. This enables the vRouter agent to learn the MAC address-IP address of the pods connected to the virtual network.
In release 2011, Contrail Networking also supports Bidirectional Forwarding and Detection (BFD) based health check to verify the liveliness of a pod. In the Contrail Command user interface (UI), you must create a BFD health check service, where the Health Check Type is assigned as VN IP List. The BFD session is enabled for a list of target IP addresses. In release 2011, Contrail Networking supports IPv4 target IP addresses. The vRouter agent learns these IP addresses through the MAC address - IP address learning feature. The BFD health check session is initiated, when the vRouter agent learns the target IP address assigned to the BFD health check service. The BFD health check monitors the target list of health check for newly learnt IP addresses. If the BFD session is detected as DOWN, the vRouter agent deletes the routes generated for the MAC address - IP address of a pod learned by the vRouter.
The vRouter agent also sends address resolution protocol (ARP) packets in regular intervals to newly learnt IP addresses. The vRouter agent performs this action to check a pod’s liveliness. If a pod responds to the ARP request sent by the vRouter, the pod is considered as UP. If the pod does not respond to the ARP packets, the pod is considered as DOWN. If vRouter identifies a pod as DOWN, it deletes the routes generated for the respective MAC address-IP address of the pod.
You must perform the following steps to enable the vRouter to dynamically learn the MAC address - IP address of a pod:
You must perform the following steps to enable BFD based healthcheck for the pods deployed on a VM:
Navigate to Services > Health Check. Click Create to create a new BFD based health check service.
Alternatively, you can also edit the properties of an existing virtual network. To edit an existing virtual network, select a virtual network from the displayed list and click the Edit (pencil) icon.
Enter values in the Create Health Check Service page according to the guidelines provided in Table 1.
Click Create.
The Health Check tab is displayed listing the newly created health check service.
Field |
Description |
|---|---|
Name |
Enter a name for the health check service you are creating. |
Health Check Type |
Select VN IP List to run health check on the IP addresses of the virtual networks. |
Protocol |
Protocol is set to BFD by default when VN IP List is selected as theHealth Check Type. BFD health check enables you to verify pod liveliness. |
Add all option |
Select this to run BFD health check for all IP addresses learned by the vRouter Agent from learning the MAC address - IP address of a pod. |
Target IP List |
Select IP addresses from list to run BFD health check on the selected IP addresses. |
Desired Min Tx Interval (milli secs) |
Enter the desired minimum transmission (Tx) interval before transmitting BFD packets. |
Required Min Rx Interval (milli secs) |
Enter the minimum interval between successive BFD packets that is supported by the system. |
Multiplier |
Enter the number of BFD packets that must be missed successively from the remote end to declare the BFD session as DOWN. |
Change History Table
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