Webinar - Building Custom Extensions With AppDynamics

AppDynamics Webinars:
Building Custom Extensions
Todd Radel, Senior Manager – Customer Advocacy

Agenda
• Introduction
• Writing a script extension
• Writing a Java extension
• Using your custom metrics
• Best practices
• Office hours

About Me
Todd Radel
SENIOR MANAGER
CUSTOMER ADVOCACY TEAM
• More than 20 years experience in the software industry
• Java, .NET, Python, Perl
• Author of the Python SDK for AppDynamics REST API
• Author of six AppDynamics Extensions: F5, Tibco EMS,
Redis, Keynote, SQL, URL Monitor
Copyright © 2015 AppDynamics. All rights reserved. 3
tradel@appdynamics.com
+1 (484) 857-2335
tradel
todd.radel
linkedin.com/in/tradel

What is an Extension?
• Plugs in to Machine Agent
• Imports additional metrics to AppDynamics

Why Use Extensions?
“I already have Graphite/Nagios/my own custom tools…”
BUT:
• Add more color to overall AppDynamics picture
• Baseline and alert on custom metrics
• Create custom dashboards
• Work towards a “single pane of glass”

Example Extensions
• Apache Server Monitor
• F5 Monitor
• ActiveMQ Monitor
…or build your own!

Use Cases
• Run a SQL query every few minutes to count
sales/signups/etc.
• Extract metrics from custom instrumentation
• Eliminate redundant tools

Anatomy of a Simple Script Extension
• Script file
• monitor.xml – describes the extension

Example
• Write an extension to count the number of files in /var/tmp
and alert if there are too many

Simple Extension Script

Script Output
name=Custom Metrics|File Count|count, value=29, aggregator=OBSERVATION,
time-rollup=CURRENT, cluster-rollup=COLLECTIVE
• name – path and name of your metric
• value – metric value
• aggregator – how to handle multiple values in one interval
• time-rollup – how to aggregate values over time
• cluster-rollup – how to aggregate values over nodes

Metric Aggregation
Aggregation Time Rollup Cluster Rollup
How should the controller handle
multiple values in a single minute?
How should values be aggregated over
time?
How should values be aggregated
across nodes in a tier?
AVERAGE
Average of all reported values in that
minute
AVERAGE
Average of all one-minute values
INDIVIDUAL
Average of metric values across each
node in the tier
SUM
Sum of all reported values in the
minute
SUM
Sum of all one-minute values
COLLECTIVE
Sum of metric values across each node
in the tier
OBSERVATION
Last reported value in the minute
CURRENT
Last reported one-minute value

Simple monitor.xml for a Script
”periodic” or “continuous”
script filename

OS-Specific monitor.xml for a Script

Anatomy of a Java Extension
• Class file or JAR file
• Dependent libraries
• Configuration file
• monitor.xml

Structuring Your Java Code
• Can be a single class
• Extend from com.singularity.ee.agent.systemagent.api.AManagedMonitor
• Override and implement execute() method
• Call getMetricWriter().printMetric() to send data

Example
• Write an extension to import metrics from the Linux
collectd(8) daemon

Sample Execute() Method

Configuring Your Extension
• Task arguments from monitor.xml are sent as first
parameter to execute() method
public TaskOutput execute(Map<String, String> args,
TaskExecutionContext taskExecutionContext)
throws TaskExecutionException {
• Configure via external file (e.g. config.yml), read the file
during execute()

Monitor.xml for Java

Installation

When to use the HTTP Listener
• When you don’t have control over the code
• When the data collector runs on another machine

Starting Machine Agent with HTTP Listener
java -Dmetric.http.listener=true
-Dmetric.http.listener.port=8000
-jar machineagent.jar

Sending Metric Data

Sending Metrics as JSON

Locating Your Custom Metrics
Tier name
Node name
Metric path

Create Custom Dashboards

Sample Custom Dashboard

Create Health Rules

Best Practices
• Make it configurable via monitor.xml or config.yml
• Allow a custom metric path
• Write portable code
• Send output to the machine agent log
• Follow our “mavenized” project structure
• Post the code on GitHub and encourage pull requests

Increasing the Agent Metric Limit
• If you don’t see all metrics in the controller UI
• Check machine agent logs for “metric limit reached”
• Add command line options and restart machine agent
• Without custom extensions:
java -jar machineagent.jar
• With extensions:
java -Xmx256m -Dappdynamics.agent.maxMetrics=10000
-jar machineagent.jar

Publishing Your Extension
• Remove any usernames/passwords/hostnames from
configuration files
• Add README.md and LICENSE files
• Post the code on GitHub
• Create new thread on AppDynamics Community to
announce and publish!

Contents of Your README.md
• Description
• Requirements
• Installation
• Configuration
• Metrics Produced
• How to Contribute (optional)
• History/Release Notes
• Screenshots

Documentation
• Extensions and Custom Metrics
• Build a Monitoring Extension Using Java
• Build a Monitoring Extension Using Scripts
• Machine Agent HTTP Listener

Sample Java code
• Apache Monitoring Extension
• URL Monitoring Extension
• Follow along as I finish these extensions!
https://github.com/tradel/collectd-monitoring-extension
https://github.com/tradel/file-count-monitoring-extension

Webinar - Building Custom Extensions With AppDynamics

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