Configuring High Availability
The high availability feature supports redundancy models with an active controller pair, or an active/standby deployment model with one backup controller supporting one or more active controllers. Each of these clusters of active and backup controllers comprises a high-availability group. All active and standby controllers within a single high-availability group must be deployed in independent conductors topology. An independent conductors topology requires all independent conductor controllers to have the same WLAN Wireless Local Area Network. WLAN is a 802.11 standards-based LAN that the users access through a wireless connection. configuration.
The High Availability feature is not supported on Standalone Conductor-Standby deployments.
The following procedure configures High Availability using the WebUI:
- For a Stand alone controller, under , select your device and then navigate to the tab.
- For a managed device, navigate to the tab.
- Expand the accordion and click . A pop-up window appears.
- In the field, enter a name for the new HA group.
- Configure an IPv4 or IPv6 address for the controller.
- Click in the or fields. The window opens. Enter an IP address.
IPv4 and IPv6 controllers can be part of the same HA group profile. However, HA works only between controllers of same IP format.
- Click the controller. The IP address of each controller must be reachable by APs and must be the IP address that appears in the tab of the controller WebUI, or in the output of the CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. command. The role can be one of the following options: drop-down list to assign a role to the
- Controller is active and serving APs. :
- Controller serves some APs and acts as a standby controller for other APs. :
- Controller does not serve APs and only acts as a standby in case of failover. :
- Click controller to the group. to add the
- (Optional) Select the controller once the controller is reachable again. When you enable this setting, the AP waits for the time specified by the parameter defined in the profile before the AP attempts to switch back from the standby controller to the original controller. check box to enable the failed over APs to attempt to connect back to its original active
- (Optional) The standby controller over-subscription feature allows a standby controller to support connections to standby APs beyond the controller's original rated AP capacity. To enable this feature, select the check box.
- (Optional) Select the check box to enable the feature. State synchronization improves failover performance by synchronizing client authentication state information from the active controller to the standby controller. (For more information about state synchronization, see Client State Synchronization).
State synchronization is not applicable for IPv6 controllers.
- (Optional) Select the controller heartbeat features, which enable faster AP failover from an active controller to a standby controller, especially in situations where the active controller reboots or loses connectivity to the network. To edit the default heartbeat threshold and interval values:
- Enter a heartbeat threshold in the controller. This value must be between 3 and 10, inclusive. field to define the number of heartbeats that must be missed before the APs are forced to failover to the standby
- Enter a heartbeat interval in the controller heartbeats are sent. This value must be between 100 and 1000 ms, inclusive. field to define how often inter-
check box to enable the high availability inter- - (Optional) If you enabled the state synchronization feature in Step , enter a pre-shared key into the and fields.
- Click .
- Click .
- In the window, select the check box and click .
The following procedure associates a controller with a High Availability group:
- For a standalone controller, under , select your device and then navigate to the tab.
- For a managed device, navigate to tab.
- Expand the accordion.
- Select a HA group from drop-down list.
- Click
- Click
- In the window, select the check box and click .
To configure a High Availability group using the command-line interface, access the CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. in config mode and issue the following commands. The high availability group profile should be configured with a pair of IPv4 controller addresses and pair of IPv6 controller addresses to allow an IPv4 or IPv6 access point to establish a connection to a standby controller.
(host) [mynode] (config) #ha group-profile <profile>
(host) [mynode] (HA group information "default") #controller <ip> role [active/dual/standby]
A controller using the high availability features must be defined as a member of a high availability group. To add a controller to the new high availability group, issue following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. command:
(host)[mynode] (config)#ha group-membership <ha-group>