The AppDynamics Controller Admin Console lets you configure certain global settings for the Controller, such as metric retention periods, UI notification triggers, tenancy mode, and accounts in multi-tenancy mode 1 . Two of the settings that an administrator can configure from the AppDynamics Controller Admin Console are:

License allocation : This setting allows you to view and manage the license usage and availability for your Controller. You can see the total number of licenses, the number of licenses in use, the number of licenses available, and the license expiration date for each agent type.  You can also allocate licenses to specific applications or accounts, and set license limits and alerts 2 .

Retention periods : This setting allows you to specify how long the Controller retains the metric data and the event data for your monitored applications. You can configure the retention periods for different types of data, such as minute-level metrics, hour-level metrics, day-level metrics, transaction snapshots, and events.  You can also configure the data purge schedule and the data backup schedule 3 .

References :  Access the Administration Console ,  License Rules ,  Data Retention

The AppDynamics REST API to retrieve metrics allows you to get values generated for metrics by specifying the path of the metric and the time frame for the data 1 .  Some of the valid reasons to use this API are 1 2 :

To archive 1-minute granularity data. The AppDynamics Controller stores metric data at different levels of granularity depending on the retention period. For example, it stores 1-minute granularity data for 8 days, 10-minute granularity data for 32 days, and 1-hour granularity data for 365 days. If you want to archive the 1-minute granularity data for longer than 8 days, you can use the API to retrieve and store the data in an external database or file system.

To calculate a new metric based on two existing metrics. The AppDynamics Controller provides some built-in metrics such as average response time, calls per minute, errors per minute, etc. However, you may want to calculate a new metric that is not available in the Controller, such as the ratio of errors to calls, or the percentage of slow transactions. You can use the API to retrieve the values of the existing metrics and perform the calculation using your own logic or formula.

To retrieve health rule violations. Health rules are the rules that define the performance and availability thresholds for your application components. When a health rule is violated, the AppDynamics Controller generates an event and optionally triggers a policy action. You can use the API to retrieve the list of health rule violations for a given application, time range, and severity level. This can help you monitor and troubleshoot the health of your application and take corrective actions if needed.  References :  Retrieve Metric Data ,  Health Rule API

The AppDynamics REST API for retrieving metrics allows you to get values generated for metrics by specifying the path of the metric and the time frame for the data 1 .  The following statements are true regarding this API 1 2 :

Metrics can be retrieved for a fixed time range. You can use the time-range-type parameter to specify a fixed time range such as BEFORE_NOW, AFTER_TIME, or BETWEEN_TIMES. You can also use the duration-in-mins parameter to specify the length of the time range in minutes.

Wildcards can be used in the REST API metric path. You can use the asterisk ( ) character as a wildcard to match any metric name or part of a metric name. For example, you can use the metric path Business Transaction Performance|Business Transactions| |*|Average Response Time (ms) to retrieve the average response time for all business transactions in all tiers.  References :  Retrieve Metric Data ,  Retrieve Metric Hierarchy

The AppDynamics Controller is a Java web application that runs on a GlassFish application server and uses a MySQL database. During the installation of the Controller, two user accounts are created by default:

The GlassFish asadmin user is the administrative user for the GlassFish server. This user has the authority to start, stop, and configure the GlassFish server and its domains. The default username for this user is  admin  and the default password is  appdynamics .  You can change the password for this user after the installation by using the  asadmin  command-line tool 1 .

The customer-specified Controller administrator account is the user account that you provide during the installation wizard. This is the account that you use to access the AppDynamics User Interface (UI) for the first time and perform various tasks such as creating applications, configuring agents, managing users and groups, and so on. You can choose any username and password for this account, but AppDynamics recommends using only ASCII characters.  You can also create additional user accounts in the Controller UI after the installation 2 .

The other options are not user accounts that are created by the Controller installation. The Elastic search root user, the REST API user, and the MySQL appd admin user are user accounts that are used internally by the Controller components and are not exposed to the end user.  The OS user that will run the controller is a user account that you need to create on the host machine before the installation, and it is not created by the Controller installation 3 .  References :  Controller Installation ,  Manage Users and Groups , and  Update the Root User and Glassfish Admin Passwords  in the AppDynamics documentation.

Before installing an AppDynamics Controller on Linux, you need to perform some preparatory tasks to ensure the system meets the requirements and the installation runs smoothly. Two of these tasks are:

Install libaio on the host machine if it does not already have it installed. This library facilitates asynchronous I/O operations on the system, which are required by the Controller. You can use the package manager of your Linux distribution to install libaio, such as yum or apt-get.  For example, on CentOS, you can run  yum install libaio 1 .

Verify that you have enough temporary (tmp) space available on the system, at least 1 GB. The Controller installation uses the tmp space to extract and install the software components.  You can check the tmp space by running  df -h /tmp 2 .  If the tmp space is insufficient, you can either free up some space by deleting unnecessary files, or specify a different temporary directory for the installation by passing the  -Djava.io.tmpdir  parameter to the installer 3 .

Other preparatory tasks include verifying the user account permissions, configuring the virus scanners, installing the netstat network utility, and setting the file descriptor limit 2 .  References :  Prepare Linux for the Controller ,  Install the Controller on Linux , and [Controller System Requirements] in the AppDynamics documentation.

AppDynamics performance profiles are predefined sets of system requirements and configuration settings that are designed to support different levels of load and scalability for the AppDynamics platform. The performance profiles range from small to extra large, depending on the number of agents, metrics, and events that the platform needs to handle. The large and extra large performance profiles differ from other profile types in the following ways:

They require an enterprise-grade database : The large and extra large performance profiles require an external MySQL database that is enterprise-grade, meaning that it has high availability, scalability, performance, and security features. The database should also have enough disk space, memory, and CPU resources to handle the expected load and growth.  The AppDynamics platform uses the database to store configuration data, metric data, event data, and analytics data 1 2 .

An alert is generated when disk space falls below 2 GB : The large and extra large performance profiles have a built-in alert mechanism that notifies the administrator when the disk space on the Controller host falls below 2 GB. This is because the Controller needs enough disk space to store temporary files, logs, backups, and snapshots. If the disk space is insufficient, the Controller may experience performance degradation, data loss, or corruption.  The administrator should monitor the disk space usage and free up space or add more disk capacity as needed 3 4 .

The other statements are false because:

A. They do not need to be installed on a bare metal server. The large and extra large performance profiles can be installed on any supported operating system, such as Linux or Windows, and on any supported platform, such as physical, virtual, or cloud.  However, the host machine should have enough CPU, memory, and network resources to meet the performance profile requirements 1 2 .

B. They do not need to be run with the High Availability Toolkit. The High Availability Toolkit is an optional tool that can be used to configure and manage a high availability deployment of the AppDynamics platform, where multiple Controllers are clustered together to provide redundancy and failover. The High Availability Toolkit can be used with any performance profile, not just the large and extra large ones. However, the High Availability Toolkit requires a license and additional hardware and software resources .

C. They are supported on Windows. The large and extra large performance profiles can be installed on Windows Server 2012, 2012 R2, 2016, or 2019, as long as the host machine meets the performance profile requirements.  However, some features or configurations may not be available or supported on Windows, such as the High Availability Toolkit, the Enterprise Console, or the Events Service 1 2 .

References :  Platform Requirements ,  Controller System Requirements ,  Controller Disk Space Requirements ,  Controller Disk Space Alert , [High Availability], [High Availability Toolkit]

AppDynamics recommends that you terminate SSL connections from agents at a reverse proxy or a load balancer in front of the Controller, rather than at the Controller itself. This improves the performance and scalability of the Controller by offloading the SSL processing to the proxy or load balancer. It also simplifies the configuration and management of SSL certificates and truststores. To enable this option, you need to configure the proxy or load balancer to accept SSL connections from agents and forward them to the Controller using HTTP. You also need to configure the agents to use SSL and point to the proxy or load balancer host and port. See  Enable SSL for the Java Agent  for an example.  References :  Agent-to-Controller Connections  and  Enable SSL and SSH for Database Agent Communications  in the AppDynamics documentation.