Secondary Connection Brokers

A secondary Connection Broker is added to a Site for redundancy. This way if the primary Connection Broker fails, the secondary Connection Broker is still available to handle the requests. Connection Brokers work in active/active manner to ensure high availability. In case of a Connection Broker failure, the remaining Connection Brokers are available to handle the load.

When you have one more secondary Connection Broker installed, the runtime data is replicated on each agent, so if any service fails, the downtime is reduced to a minimum. In addition, any active Connection Broker is used for authentication purposes.

The primary Connection Broker performs the same tasks as secondary Connection Brokers but has additional responsibilities. It manages certain processes that must be managed by a single Connection Broker.

The following table lists processes managed by the primary Connection Broker and Secondary Connection Brokers:

Process
Primary Connection Broker
Secondary Connection Broker

Handles administration sessions

Yes (Primary Site Connection Broker)

no

Manages system settings

yes

no

Replicates RAS settings changes

yes

yes

Keeps RAS settings change audit

yes

optional

Monitor Performance counters of Site VMs

yes

yes

Monitor Runtime Sessions

yes

yes

Monitor Runtime Applications / Processes

yes

yes

Manages Application package states

yes

yes

Send Licensing information & heartbeat

yes (Primary site Connection Broker)

no

Monitors other Site states

yes

no

Process and send CEP information

yes

no

Send information to reporting server

yes

no

Manages Schedulers

yes

no

Device Manager Shadowing

yes Primary site Connection Broker )

no

Send System alert email notifications

yes

yes

TOTP - registration

yes

yes

Email OTP - registration

yes

yes

Manages templates versioning and distribution

yes

yes

Clone hosts from templates

yes

yes

Host pool auto scaling

yes Primary site Connection Broker)

no

Manages Web authentication

yes

yes

Manages Credentials authentication

yes

yes

Manages Smart card authentication

yes

yes

Validates Policies

yes

yes

Provides configuration to HALB devices

yes

yes

Distributes configuration changes to other roles & agents

yes

yes

Due to the additional load on the Primary Connection Broker, agent connection load will not be distributed equally. The following system is used:

Number of CBs
Primary CB agent connections
Secondary CB agent connections

1

100%

2

40%

60%

3

20%

40% each

4

10%

30% each

5 or more

0%

100 / number of secondary PAs

However, if you specify that an agent is managed by a specific Connection Broker, this will be preferred.

Planning for secondary Connection Brokers

RAS Connection Brokers running on the same Site communicate with each other and share the load. The amount of data being transmitted from one agent to another is quite large, so a reliable high-speed communication channel must be ensured (e.g. a subnetwork can be configured for Connection Broker communications).

When adding a secondary Connection Broker to a Site, you specify an IP address for it. Make sure that the IP addresses of all agents belong to the same network segment. The port that Connection Brokers use to communicate with each other is TCP 20030.

In general, the N+1 redundancy approach should be used per Site. Note that for auto-promotion you should have at least three Connection Brokers (auto-promotion is described later in this section). There's no physical limit to how many Connection Brokers you can add to a Site. However, the best results are achieved with only two-three agents present. The three-agent scenario is highly recommended, especially when you have Providers and want to enable high availability for VDI.

Adding more than two secondary Connection Brokers to a Site may have an adverse effect and actually degrade the system performance due to the data replication taking place. Note that this does not apply to secondary Connection Brokers in standby mode, which is explained in Configuring RAS Connection Brokers.

Adding a secondary RAS Connection Broker to a Site

To add a secondary Connection Broker:

  1. In the RAS console, navigate to Farm > <Site> > Connection Brokers.

  2. Click the Tasks drop-down list and choose Add to launch the Add RAS Connection Broker wizard.

  3. The Server field specifies the FDQN or IP address of the server that hosts the RAS Connection Broker. To automatically resolve IP address to FQDN, enable the global Name Resolution option. For details, see Host Name Resolution.

  4. The IP field specifies the server IP address. Click the Resolve button to obtain the IP address automatically using the FQDN specified in the Server field.

  5. The Alternative IPs field specifies one or more alternative IP addresses, separated by a semicolon. These addresses will be used if RAS Secure Gateways fail to connect to the RAS Connection Broker using its FQDN or the address specified in the IP field. This can happen, for example, if Secure Gateways are connecting from a different network, which is not joined to Active Directory.

  6. Select the Install a Secure Gateway with a Connection Broker option if you also want to install a RAS Secure Gateway on the specified server. If you select this option, you may also select the Enable HTML5 Gateway option (for more info, see Configure User Portal).

  7. Select the Add Firewall Rules option to automatically configure the firewall on the server. See Port Reference for details.

  8. Click Next.

  9. On the next page, click Install to install the RAS Connection Broker on the server. The Installing RAS Redundancy Service dialog opens.

  10. Select the server on which the RAS Connection Broker is to be installed and click Install.

  11. Click Done.

  12. Click OK to add the server to the Farm.

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