(4.4.11) Duplex Deployment

Active-Passive (Primary / Secondary) Setup

To configure the Connector in Active-Passive mode, set the value of attribute “GRC_CONSUMER_PRIORITY” in Connector configuration. For the Primary Connector, set the value of this attribute to “127” without quotes. For the Secondary Connector, set the value of this attribute to “100” without quotes.

Active-Passive mode has the following configurations.

Configurations for Site-1

Primary-AMQ: broker-1, Secondary-AMQ: broker-2

Generic Connector Configuration should look like, For detailed description of the GC please consult properties

Property	Value
ActiveMq_Timeout	10000
GRC_CONSUMER_PRIORITY	127
RANDOMIZE	false
PRIORITY_BACKUP	true
ActiveMq_URL_1	primary-url-of-amq:port
ActiveMq_URL_2	secondary-url-of-amq:port

Configurations for Site-2

Primary-AMQ: broker-1, Secondary-AMQ: broker-2, For detailed description of the GC please consult properties.

Property	Value
ActiveMq_Timeout	10000
GRC_CONSUMER_PRIORITY	100
RANDOMIZE	false
PRIORITY_BACKUP	true
ActiveMq_URL_1	primary-url-of-amq:port
ActiveMq_URL_2	secondary-url-of-amq:port

Failover Scenarios

Following table shows different failover scenarios and its impact on the Connector Clients.

No.	Scenario	Behavior
1	AMQ-1 is down while GC-1 is active	AMQ-2 will take over. GC-1 will automatically connect to AMQ-2 and all client requests will be processed by the same GC-1 instance because of its higher consumer priority. Request Flow: Client-App → AMQ-2 → GC-1 Response Flow: GC-1 → AMQ-2 → Client-App
2	AMQ-2 and GC-1 are down while AMQ-1 and GC-2 are up	AMQ-1 will take over and all client requests will be processed by GC-2 because it has the second highest priority after GC-1. Request Flow: Client-App → AMQ-1 → GC-2 Response Flow: GC-2 → AMQ-1 → Client-App
3	Both AMQ-1 and GC-1 are down	AMQ-2 and GC-2 will start receiving requests. GC-2 will acquire all agent’s XMPP subscription and will start processing requests. Request Flow: Client-App → AMQ-2 → GC-2 Response Flow: GC-2 → AMQ-2 → Client-App
4	GC-1 restores	GC-1 will start receiving requests and will grab XMPP connection of all the active agents because of its higher consumer priority. GC-2 will again be in stand-by mode.
5	Link between Connector-1 and Connector-2 is down	In this case AMQ network of broker will not be functional and GCs won’t be able to communicate to sync agents either. So, both GCs will be functioning independently
6	AMQ-1 restores while GC-1 is still down	If AMQ-2 is active and client application is connected to AMQ-2 then all requests will be processed by GC-2 even though GC-1 is active and connected to AMQ-1. Request Flow : Client-App → AMQ-2 → GC-2 Response Flow: GC-2 → AMQ-2 → Client-App
7	GC-1 is down while both AMQs are active	Requests will be processed by GC-2 going through the network-of-brokers. Request Flow : Client-App → AMQ-1 → AMQ-2 → GC-2 Response Flow: GC-2 → AMQ-2 → AMQ-1 → Client-App
8	GC-2 is down while both AMQ are active	In active passive mode it will have no effect on request and response flow. Because AMQ-2 doesn’t get any request from Client-App until AMQ-1 goes down.

Failover is handled in a way if any component goes down, passive components take over in a seamless way.

Active-Active Setup

For an Active-Active deployment, Failover URL is set to use the local AMQ as primary and remote AMQ as secondary.

For GC-1, the configuration would look like this, For a detailed description of the GC please consult properties

Property	Value
ActiveMq_URL_1	[AMQ-1]:61616
ActiveMq_URL_2	[AMQ-2]:61616
GRC_CONSUMER_PRIORITY	127
PRIORITY_BACKUP	true
Finesse_1	http://Finesse-1/finesse/api/
SERVER_ADDRESS_1	Finesse-1
Finesse_2	http://Finesse-2/finesse/api/
SERVER_ADDRESS_2	Finesse-2

For GC-2, the configuration would look like, For detailed description of the GC please consult properties

Property	Value
ActiveMq_URL_1	[AMQ-2]:61616
ActiveMq_URL_2	[AMQ-1]:61616
GRC_CONSUMER_PRIORITY	100
PRIORITY_BACKUP	true
Finesse_1	http://Finesse-2/finesse/api/
SERVER_ADDRESS_1	Finesse-2
Finesse_2	http://Finesse-1/finesse/api/
SERVER_ADDRESS_2	Finesse-1

Where [AMQ-1] should be replaced with the IP / machine-name of ActiveMQ-1 and [AMQ-2] should be replaced with the IP / machine-name of ActiveMQ-2. Finesse-1 is the IP/name of Finesse-1 server and Finesse-2 is IP/name of the Finesse-2 server.

Both Connectors will have its local AMQ as primary brokers and both Connector instances will be serving agents requests in parallel. All client requests received by Connector-1 are handled by Connector-1 and all requests received by Connector-2 will be handled by Connector-2. In case of failure of any component at any Connector instance, the other Connector instance will take over and handle the request.

We have achieved it using ActiveMQ configurable properties specifically Consumer priority, Priority Backup, and building a Connector Sync mechanism in Generic Connector.

Failover Scenarios

No.	Scenario	Behavior
1	AMQ-1 is down while GC-1 is active	AMQ-2 will take over and all client requests will be processed by the same GC-1 instance because of its higher consumer priority.
2	Both AMQ-1 and GC-1 is down	AMQ-2 and GC-2 will start receiving requests. GC-2 will acquire all agent’s XMPP subscription and will start processing requests.
3	GC-1 restores	Connector-2 will continue to process requests until connectivity between Client application and Connector-2 is lost or Connector-2 is down.
4	Link between Connector-1 and Connector-2 is down	Both connector instances serve requests independently.
5	AMQ-1 restores while GC-1 is still down and AMQ-2 is also down	Client will send request to AMQ-1. AMQ-1 will send the request to GC-2 because GC-1 is down. Request Flow: Client-App-1 → AMQ-1 → GC-2 Response Flow: CGC-2 → AMQ-1 → Client-App-1
6	GC-1 is down while both AMQ are active	The request flow will be the same as no. 5
7	GC-2 is down while both AMQ are active	AMQ-2 requests will be redirected to AMQ-1 and GC-1 will handle all requests. Request Flow: Client-App-2 → AMQ-2 → AMQ-1 → GC-1 Response Flow: GC-1 → AMQ-1 → AMQ-2 → Client-App-2