Cloud High Availability

Amazon Web Services cloud and Microsoft Azure cloud resources are hosted in multiple locations worldwide. These locations are composed of Regions and Availability Zones. Each Region is a separate geographic area and each Region has multiple, isolated locations known as Availability Zones.

In the cloud, resources can be deployed across different regions or multiple locations within a region for fault tolerance reasons. AWS Availability Zones and Azure Availability Sets (or Fault Domains; Azure currently supports different resource groupings within a physical datacenter) are examples of cloud high availability offerings. When deploying CloudEOS and vEOS Routers to enhance your cloud's network capability, deploy the CloudEOS and vEOS Routers as a high availability pair using the CloudEOS and vEOS Cloud High Availability feature that fits your cloud's high availability design.

The Cloud High Availability (Cloud HA) feature adds support to make the CloudEOS and vEOS Router deployment more resilient to various failure scenarios in the cloud, such as:
  • CloudEOS and vEOS Router instance goes down due to underlying cloud infrastructure issues.
  • CloudEOS and vEOS Router instance is unable to forward traffic due to connectivity issues in the cloud infrastructure.
  • CloudEOS and vEOS Router experiences an internal issue leading to unavailability.

CloudEOS and vEOS Router HA pair with Cloud HA is an active-active deployment model for different cloud high availability design in a region. Each CloudEOS and vEOS Router in an HA pair provides enhanced routing capabilities as the gateway (or next-hop router for certain destinations) for the subnets to which the CloudEOS and vEOS routers connect. The two CloudEOS and vEOS Router peers monitor the liveliness of each other by using Bidirectional Forwarding Detection (BFD) between the router interfaces. In case of the cloud infrastructure issues or CloudEOS and vEOS router failure, the active CloudEOS and vEOS router takes over as the gateway or next-hop for the subnets that were connected to the peer router through cloud-specific API calls that modify the corresponding cloud route table(s) according to pre-configured information.