Managing relay balancers

The Relay Balancers mechanism makes it possible to elect one or more Client Management agents so they can be queried by other agents to get their parent relay. This definition makes this mechanism very similar to the Relay Lists. However, the criterion to find and return the parent for each client is different. The Relay Lists mechanism is stateless and tries to find the best parent relay based on the client IP address list. The Relay Balancers mechanism does not take this information into consideration. It simply allocates a parent relay, based on their current client count and capacity. This is known as a lease. One key difference with Relay Lists is that a balancer remembers all the leases that have been offered in the past. If a client requests a parent more than once, the same relay will be returned each time. This mechanism is helpful if you simply want to define relays and let them be assigned to clients automatically.

Relay Balancer configurations can be updated and reassigned at any time. In this case, the Relay Balancer Server will perform the required operations to reflect the changes. If a relay is removed from the configuration, all its leases are also removed from the Relay Balancer cache. If a relay is added, then it becomes available for the next offers, without impacting the current leases. Finally, if capacity is increased or decreased, you can also modify the leases to respect the new value.

This mechanism tries to maintain the same child count for each relay in the balancer configuration, regardless their capacity to ensure a distributed load for the relays. 

To change the functionality behavior, you can configure the parameters in the following manners: 

• The lease time defines the highest time in hours after which a lease is automatically removed from the balancer cache.
• The lease time to leave is similar, but instead of checking the lease using its creation time, it performs the verification based on the last offer time.

To disable the test, set the special value to zero for these parameters. 

You can assign a Relay Balancer Server with multiple Relay Balancer configurations. In this case, the resulting configuration is the aggregate of all the received configurations.

You can also assign a Relay Balancer configuration to multiple Relay Balancer servers. In this case, the Relay Balancers do not take into account the leases offered by the other balancers, which may drive to the relays capacity not being respected. To keep things simple, it is recommended to assign a single Relay Balancer configuration to the Relay Balancer servers and to avoid assigning the same configuration to multiple balancers.

To enable Relay Balancer capabilities

1. On the BMC Client Management console, go to Global Settings > ClientManagementAdmin > Security Profile.
2. In the Capabilities window, enable the Relay Balancers capabilities such as View, Manage, Assign.

To create a Relay Balancer configuration

1. On the BMC Client Management console, select Global Settings > Relay Selection > Relay Balancers.
2. Select Create Relay Balancer.
3. In the Properties window type a name for the relay balancer.
4. Click OK.
5. Select the New Relay Balancer node.
6. In the Configuration tab, right-click in the pane, and select Add Relay.
7. In the Select a relay window, select the devices to be relay servers.
   For each relay, you can edit the Network Address, HTTP Port, Capacity and Description fields
8. Click OK.
   The relay is added to the Relay Balancer configuration.

Managing Relay Balancer configuration 

• You can copy and paste Relay Balancer configurations.
• You can export an existing Relay Balancer configuration. The supported file format is XML.
• You can import an existing Relay Balancer configuration. The supported file format is XML. The imported configuration appears under the Relay Balancers node.
• You cannot assign a Relay Balancer if its configuration is empty.

To assign Relay Balancer configurations to Relay Balancer servers

You can deploy Relay Balancer configurations on devices that are designated to be Relay Balancer servers. Each designated Relay Balancer server should have the latest Relay Balancer configuration because client devices seek their parent from the configured relays. Examples of use cases are client devices that belong to a rollout targets or new client devices added to the network that would connect to a Relay Balancer server to get their parent relay.

To assign Relay Balancer configurations to relay servers:

1. On the BMC Client Management console, select Global Settings> Relay Selection > Relay List.
2. Select a Relay Balancer configuration, and then select Assigned Objects > Device Groups/Devices.
3. Right-click Devices/Device Groups and select Assign Device Group/Assign Device.
4. In the Assign to Device window, select any BCM agent that can be assigned to a Relay Balancer configuration.
   BMC Client Management automatically assigns the Relay Balancer configuration to the selected devices.
5. In the Devices window, verify that the device status is Assigned, which means that the Relay Balancer configuration is now available on the Relay Balancer server.

 To assign Relay Balancer configurations to devices or device groups

1. Depending on where you want to assign an object, from the BCM console, go to the following nodes:
   1. To assign an object to a device, go to the Device Topology node.
   2. To assign an object to a device group, go to the Device Groups node.
2. Select the device, go to Assigned Objects, and select Relay Balancers.
3. In the Relay Balancers window, right-click and select Assign Relay Balancer.
4. From the Assign a Relay Balancer window, select the configuration that you want to assign to the device or device group.
5. Click OK.
   For more information about managing assigned object types, refer to Managing assigned object types.

To unassign or activate Relay Balancer configurations to devices or device groups

1. On the selected device or device group, go to Assigned Objects and select Relay Balancers.
2. In the Relay Balancers window, right-click the configuration and select the function you want to perform on it.

Configure agent communication parameters

After you configure and deploy the Relay Balancer configurations, you want to configure the agent communication parameters to define the Relay Balancer Server URL. There are a couple of scenarios: rollout of Client Management agents and managing existing agent - in which agent communication parameters can be updated based on your network configuration. For example, to define communication between agents and relay or master servers, you choose a combination of Static relays and Relay Balancer server as the two methods of communication.

For more information, refer to the following topics: Agent communication parameters, Relay Balancer Server parameters.

Configuring relay module parameters

You set the relay module parameters only for the Relay Balancer Server devices. After you configure the agent communication parameters, you want to configure the agent parameters related to Relay Balancer communication method, such as Balancer Lease Time (hours), Balancer Lease TTL (hours), Relay Balancer Synchronize at Startup, Relay Balancer Additional Automatic Synchronization Hour, Relay Balancer Minimum Gap between Two Automatic Synchronizations (sec). For more information, see Setting the Relay module parameters