Citrix Application Delivery Management service

Configure agents for multisite deployment

Agents work as an intermediary between the Citrix Application Delivery and Management and the discovered instances across different data centers and public clouds. Citrix Application Delivery and Management supports agent failover within a data center or a public cloud.

The following are the benefits of installing agents:

  • The configured instances to an agent send the unprocessed data directly to the agent instead of Citrix Application Delivery and Management. Agent does the first level of data processing and sends the processed data in compressed format to the Citrix Application Delivery and Management for storage.

  • Agents and instances are co-located in the same data center or cloud so that the data processing is faster.

  • Clustering the agents provides redistribution of Citrix ADC instances on agent failover. When one agent in a site fails, traffic from Citrix ADC instances switches to another available agent in the same site.

Architecture

The following figure illustrates Citrix ADC instances configured on multiple agents in a data center and public cloud to achieve agent failover:

Citrix Application Delivery and Management agents configured for multisite deployment

The public cloud has four ADC instances and two Citrix Application Delivery and Management agents. The enterprise data center also have four ADC instances and two Citrix Application Delivery and Management agents. Each agent is configured with two ADC instances.

The agents receive data directly from the configured instances. After agent receives the data, agent processes the data and sends to the Citrix Application Delivery and Management in a compressed format. Agents communicate with the Citrix Application Delivery and Management server over a secure channel.

On public cloud, when Citrix Application Delivery and Management Agent 1 becomes inactive (DOWN state), agent failover occurs. Citrix Application Delivery and Management redistributes the ADC instances of Citrix Application Delivery and Management Agent 1 with Citrix Application Delivery and Management Agent 2. The instance redistribution occurs on an enterprise data center if one of the agents fails in the data center.

To install a Citrix Application Delivery and Management agent, see Install the Citrix Application Delivery and Management Agent.

Citrix Application Delivery and Management Agent failover

The agent failover can occur in a site that has two or more registered agents. When an agent becomes inactive (DOWN state) in the site, the Citrix Application Delivery and Management redistributes the ADC instances of the inactive agent with other active agents.

Important

  • Citrix Application Delivery and Management agent failover does not consider CPX instances.

  • Ensure Agent Failover feature is enabled on your account. To enable this feature, see Enable or disable Citrix Application Delivery and Management features.

  • If an agent is running a script, ensure that script is present on all the agents in the site. Therefore, the changed agent can run the script after agent failover.

To attach a site to an agent in the Citrix Application Delivery and Management GUI:

  1. Navigate to Infrastructure > Instances > Agents.

  2. Select an agent that you want to attach to a site.

  3. Specify the site from the list. If you want to add a new site, click Add.

  4. Click Save.

To achieve an agent failover, select Citrix Application Delivery and Management agents one by one and attach to the same site.

For example, two agents 10.106.1xx.2x and 10.106.1xx.7x are attached and operational in the Bangalore site. If one agent becomes inactive, Citrix Application Delivery and Management detects it and displays the state as down.

When a Citrix Application Delivery and Management agent becomes inactive (Down state) in a site, Citrix Application Delivery and Management waits for few minutes for the agent to become active (Up state). If the agent remains inactive, Citrix Application Delivery and Management automatically redistributes the instances among available agents in the same site. This redistribution may take approximately 10-15 minutes.

Citrix Application Delivery and Management triggers instance redistribution every 30 minutes to balance the load among active agents in the site.

The instances attached and automatically reconfigured to agents in the same site for trap destination, syslog server, and analytics.

Configure agents for multisite deployment