Smart Access Gateway (SAG) supports high availability (HA). This topic describes how to configure HA for SAG devices in the SAG console to prevent single point of failures (SPOFs).

Prerequisites

  • Two SAG devices are purchased and the version of the SAG instance is 1.8.0 or later.
  • The two SAG devices used to implement HA are of the same device type.
  • The ports of the two SAG devices used to implement HA are assigned the same role.
  • The IP addresses of the peer ports used to connect the two SAG devices fall into the same CIDR block.

Background information

Static HA combines multiple routers into one virtual router. The IP address of the virtual router is used as the default gateway address for hosts in the LAN to establish connections with external networks. When an error occurs in the active gateway device, the HA feature chooses a standby device as the new active device to forward network traffic. HA maintains connections between networks. Dynamic HA does not require virtual IP addresses. The system runs health checks on the gateway devices. When an error occurs in the active gateway device, connections are automatically switched to a standby device.

SAG supports HA pairs that consist of two SAG devices. The active and standby devices are specified by the system. You can check the active and standby SAG devices in the SAG console. If an error occurs in the active device, network connections are automatically switched to the standby device. When the active device becomes functional again, connections are switched back to the active device.

Procedure

  1. Log on to the Smart Access Gateway console.
  2. Use one of the following methods to open the Device Management tab.
    • Click the ID of the target SAG instance. On the instance details page that appears, click the Device Management tab.
    • Find the target SAG instance and choose The More icon > Device Management in the Actions column.
  3. On the Device Management tab, click Manage HA.
  4. In the HA Information section, click the Edit icon.
  5. In the Configure HA dialog box that appears, select an HA mode.
    The following table describes the parameters.
    Parameter Description
    HA Mode Select whether to enable or disable HA.
    • To disable HA, select Disable.
    • If you select Static, static HA is enabled. This mode applies to scenarios that use static routing. You must specify the port and virtual IP address.
    • If you select Dynamic, dynamic HA is enabled. This mode applies to scenarios that use dynamic routing.
    Port This parameter is required if you choose to enable static HA mode. Select the device port that uses static routing.
    Virtual IP Enter the virtual IP address of the SAG devices. Enter the virtual IP address in dotted decimal notation, for example, 192.168.0.2.
    Note
    • The specified virtual IP address and the IP address of the port must fall into the same CIDR block, and cannot overlap with IP addresses that are already assigned to other ports in the same CIDR block.
    • The active and standby SAG devices must have the same virtual IP address.
    • You must set the next hop of the Alibaba Cloud-facing route of the core switch to the specified virtual IP address.
  6. Click Save.