Citrix Application Delivery Management

Configure on-prem agents for multisite deployment

In the earlier versions of Citrix ADM, Citrix ADC instances deployed in remote data centers can be managed and monitored from Citrix ADM running in a primary data center. Citrix ADC instances sent data directly to the primary Citrix ADM that resulted in consumption of WAN bandwidth. Also, processing of analytics data utilizes CPU and memory resources of the primary Citrix ADM.

You can have data centers located across the globe. Agents play a vital role in the following scenarios:

  • To install agents in remote data centers so that there is reduction in WAN bandwidth consumption.

  • To limit the number of instances directly sending traffic to primary Citrix ADM for data processing.

Note

  • Installing agents for instances in remote data center is recommended but not mandatory. If necessary, users can directly add Citrix ADC instances to primary Citrix ADM.

  • If you have installed agents for one or more remote data centers, then the communication between the agents and the primary site is through floating IP address. For more information, see port.

  • You can install agents and apply pooled licenses to the instances at one or more remote data centers. In this scenario, the communication between the primary site and one or more remote data centers is through the floating IP address.

From Citrix ADM 12.1 or later, instances can be configured with agents to communicate with the primary Citrix ADM located in a different data center.

Agents work as an intermediary between the primary Citrix ADM and the discovered instances across different data centers. Following are the benefits of installing agents:

  • The instances are configured to agents so that the unprocessed data is sent directly to agents instead of primary Citrix ADM. Agents do the first level of data processing and send the processed data in compressed format to the primary Citrix ADM for storage.

  • Agents and instances are co-located in the same data center 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 is switched to another available agent in the same site.

    Note

    The number of agents to be installed per site depends on the traffic being processed.

Architecture

The following figure shows Citrix ADC instances in two data centers and Citrix ADM high availability deployment using multisite agent-based architecture.

Multisite-architecture

The primary site has the Citrix ADM nodes deployed in a high availability configuration. The Citrix ADC instances in the primary site are directly registered with the Citrix ADM.

In the secondary site, agents are deployed and registered with the Citrix ADM server in the primary site. These agents work in a cluster to handle continuous flow of traffic in case an agent failover occurs. The Citrix ADC instances in the secondary site are registered with the primary Citrix ADM server through agents located within that site. The instances send data directly to agents instead of primary Citrix ADM. The agents process the data received from the instances and send it to the primary Citrix ADM in a compressed format. Agents communicate with the Citrix ADM server over a secure channel and the data sent over the channel is compressed for bandwidth efficiency.

Get started

  • Install the agent in a data center

    • Register the agent

    • Attach the agent to a site

  • Add Citrix ADC instances

    • Add new instance

    • Update an existing instance

Install the agent in a data center

You can install and configure the agent, to enable communication between the primary Citrix ADM and the managed Citrix ADC instances in another data center.

You can install an agent on the following hypervisors in your enterprise data center:

  • Citrix Hypervisor

  • VMware ESXi

  • Microsoft Hyper-V

  • Linux KVM Server

Note

On-prem agents for multisite deployment are supported only with Citrix ADM high availability deployment.

Before you begin installing the agent, ensure you have the required virtual computing resources that the hypervisor must provide for each agent.

Component Requirement
RAM 32 GB
Virtual CPU 8 CPUs
Storage space 30 GB
Virtual Network Interfaces 1
Throughput 1 Gbps

Ports

For communication purposes, the following ports must be open between the agent and Citrix ADM on-prem server.

Type Port Details
TCP 8443, 7443, 443  For outbound and inbound communication between agent and the Citrix ADM on-prem server.

The following ports must be open between the agent and Citrix ADC Instances.

Type Port Details
TCP 80 For NITRO communication between agent and Citrix ADC or Citrix SD-WAN instance.
TCP 22 For SSH communication between agent and Citrix ADC or Citrix SD-WAN instance. For synchronization between Citrix ADM servers deployed in high availability mode.
UDP 4739 For AppFlow communication between agent and Citrix ADC or Citrix SD-WAN instance.
ICMP No reserved port To detect network reachability between Citrix ADM and Citrix ADC instances, SD WAN instances, or the secondary Citrix ADM server deployed in high availability mode.
SNMP 161, 162 To receive SNMP events from Citrix ADC instance to agent.
Syslog 514 To receive syslog messages from Citrix ADC or Citrix SD-WAN instance to agent.
TCP 5557 For logstream communication between agent and Citrix ADC instances. 

Register the agent

  1. Use the agent image file downloaded from the Citrix download site and import it in to your hypervisor. The naming pattern of the agent image file is as follows, MASAGENT-<HYPERVISOR>-<Version.no>. For example: MASAGENT-XEN-13.0-xy.xva

  2. From the Console tab, configure Citrix ADM with the initial network configurations.

  3. Enter the Citrix ADM host name, IPv4 address, and gateway IPv4 address. Select option 7 to save and quit the configuration.

    Register 1

  4. After the registration is successful, the console prompts to log on. Use nsrecover/nsroot as the credentials.

  5. To register the agent, enter /mps/register_agent_onprem.py. The Citrix ADM agent registration credentials are displayed as shown in the following image.

  6. Enter the Citrix ADM floating IP address and the user credentials.

    Register 2

After the registration is successful, the agent restarts to complete the installation process.

After the agent restarts, access the Citrix ADM GUI, from the main menu go to the Networks > Agents page to verify the status of the agent. The newly added agent is displayed in Up state.

Register 3

Note

The Citrix ADM displays the version of the agent and also checks if the agent is on the latest version. The download icon signifies that the agent is not on the latest version and needs to be upgraded. Citrix recommends that you upgrade the agent version to the Citrix ADM version.

Attach an agent to a site

  1. Select the agent and click Attach Site.

  2. In the Attach site page, select a site from the list, or create a site using the plus (+) button.

  3. Click Save.

    Note

    • By default, all newly registered agents are added to the default data center.

    • It is important to associate the agent with the correct site. In the event of an agent failure, the Citrix ADC instances assigned to it are automatically switched to other functioning agents in the same site.

    Agent an agent to a site

Agent actions

You can apply various actions to an agent under Networks > Agents > Select Actions.

Under Select Action, you can use the following features:

Install a new certificate: if you need a different agent certificate to meet your security requirement, you can add one.

Change the default password: to ensure security of your infrastructure, change the default password of an agent.

Generate a technical support file: generate a technical support file for a selected Citrix ADM agent. You can download this file and send it to Citrix technical support for investigation and troubleshooting.

Add Citrix ADC instances

Instances are Citrix appliances or virtual appliances that you want to discover, manage, and monitor from Citrix ADM through agents. You can add the following Citrix appliances and virtual appliances to Citrix ADM or agents:

  • Citrix ADC MPX

  • Citrix ADC VPX

  • Citrix ADC SDX

  • Citrix ADC CPX

  • Citrix Gateway

  • Citrix SSL Forward Proxy

  • Citrix SD-WAN WO

For more information, see Add instances to Citrix ADM.

Attach an existing instance to the agent

If an instance is already added to the primary Citrix ADM, you can attach it to an agent by editing an agent.

  1. Navigate to Networks > Instances and select the instance type. For example, Citrix ADC.

  2. Click Edit to edit an existing instance.

  3. Click to select the agent.

  4. From the Agent page, select the agent with which you want to associate the instance and then click OK.

    Note

    Ensure to select the Site with which you want to associate the instance.

Access the GUI of an instance to validate events

After the instances are added and agent is configured, access the GUI of an instance to check if the trap destination is configured.

In Citrix ADM, navigate to Networks > Instances. Under Instances, select the type of instance you want to access (for example, Citrix ADC VPX), and then click the IP address of a specific instance.

Instance GUI

The GUI of the selected instance is displayed in a pop-up window.

By default, the agent is configured as the trap destination on the instance. To confirm, log on to the GUI of the instance and check the trap destinations.

Important

Adding an agent for Citrix ADC instances in remote data centers is recommended but not mandatory.

In case you want to add the instance directly to the primary MAS, do not select an agent while adding instances.

Citrix ADM 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 ADM redistributes the ADC instances of the inactive agent with other active agents.

Important

  • Ensure the Agent Failover feature is enabled on your account. To enable this feature, see Enable or disable ADM 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 ADM GUI, see Attach an agent to a site.

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

For example, two agents 10.106.1xx.2x and 10.106.1xx.3x are attached and operational in the Bangalore site. If one agent becomes inactive, Citrix ADM detects it and displays the state as down.

When a Citrix ADM agent becomes inactive (Down state) in a site, Citrix ADM waits for five minutes for the agent to become active (Up state). If the agent remains inactive, Citrix ADM automatically redistributes the instances among available agents in the same site.

Agent cluster

Citrix ADM triggers instance redistribution every 30 minutes to balance the load among active agents in the site.

Configure on-prem agents for multisite deployment