KickStarter Series 15 Minutes Introduction to AppDynamics
©Karun Subramanian 2
Contents
What is AppDynamics and how it can save the day? ........................................................................................................................... 3
The plumbing – How does it work? ...................................................................................................................................................... 4
How can I get started, really? ............................................................................................................................................................... 6
Configure your first Java Agent ............................................................................................................................................................ 7
Look inside your Java Application, like never before .........................................................................................................................12
Get alerted before things get worse ..................................................................................................................................................13
Monitor your hardware too ...............................................................................................................................................................14
Where to go next? ..............................................................................................................................................................................15
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What is AppDynamics and how it can save the day?
AppDynamics is a leading Application Performance Management (APM) product. It is a tool that
monitors your Application Infrastructure and gives you code level visibility. It is supported for all major
technologies (Java, .NET, PHP, Node.js, NOSQL etc) and can be installed either as on-premise or as
SaaS (Software As a Service) solution.
A piece of software called Agent is installed in the Application to be monitored. The Agent collects the
performance metrics and sends them to a Server process called Controller. Controller processes the
metrics and presents them via Web Browser. A monitoring analyst can configure Alerts and generate
reports using the Web Interface.
The agent constantly monitors the application. Since it uses byte code instrumentation technology,
Agent has hooks to every line of code. This is how AppDynamics is able to provide code level visibility.
Agents are available for most of the popular technologies.
Most of the monitoring capability is ‘out of the box’, including and Alerts. Another neat ‘out of the box’
feature is the ‘Application Flow Mapping’. AppDynamics discovers various subsystems and backends
and draws them beautifully on the browser. At times, you will be surprised to discover about
backends that you never thought your application was talking to. In addition AppDynamics ‘learns’
application behavior and automatically sets baselines, and alerts when the deviation from baseline is
not normal (anomaly).
The image below shows a typical AppDynamics Controller UI.
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Image Source: www.appdynamics.com
AppDynamics employs the concept of ‘Business Transaction’ (BT). A BT represents a service provided
by your application that is invoked by the user. All involved subsystems and backends for a given BT
are tracked and reported by AppDynamics. BTs are automatically discovered but you can define your
own BTs as well.
Using a special type of agent called Machine Agent’, AppDynamics can monitor hardware too. Basic
resource utilization such as CPU,Memory,Disk usage are monitored. Machine agents are available for
most OS (Windows, Linux, Solaris etc).
AppDyanmics lets you write your own extension using shell scripts or Java. It is a very powerful feature
that enables you to monitor virtually anything. There are numerous extensions already developed by
the community and available for download.
The plumbing – How does it work?
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Image Source: AppDynamics.com
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The controller is the engine of AppDynamics. It receives monitoring data from Agents installed on the
Application servers (or Database Servers, Web Servers etc). The user accesses and manages the
monitoring data by connecting to the Controller via web browser (usually at port 8090). It helps to
understand the terminology used in AppDynamics to know how it works.
Node
A node is a monitored Server or JVM (or CLR). Typically the node corresponds to an individual
Application Server (Physical or Virtual)
Tier
A tier is a logical grouping of nodes generally relating to a particular business function. Note that an
agent cannot belong to more than one Tier
Business Application
A Business Application is the top level container in AppDynamics. It contains Tiers. Role Based Access
Controls in the Controller UI are implemented at the Business Application Level
Backends
Backends are any external systems to the AppDynamics agent that are not instrumented. For example,
if a .NET Application that is instrumented makes a call to a SQL Server Database Server, if the SQL
Server is not instrumented with AppDynamics agent, it is considered a ‘backend’ in the .NET
application. The response time for the backend calls are recorded (along with load, errors etc).
However, deeper level metrics are possible only when the remote system is instrumented.
AppDynamics automatically recognizes most of the popular backend systems.
How can I get started, really?
In order to get the taste of AppDynamics, you can get started for free. At a high level, here is what you
have to do:
1. Identify a Server that can serve as AppDynamics Controller. Controller is available for the
following platforms
Windows (32 and 64 bit)
Linux (32 and 64 bit)
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Mac OS (64 bit)
2. Download and install AppDynamics Controller (https://download.AppDynamics.com).
Installation is pretty straight forward.
3. Download and install one of the App agents (Agents are available for the following):
JVM (Oracle HotSpot, JRockit, IBM JVM)
.NET
PHP
Node.js
Python
WebServer on Linux (Apache)
DB Agent (DB2,Oracle,MySQL,SQL Server, PostgreSQL, Sybase IQ)
4. Configure the App agent; Restart the Application and start monitoring like never before
(instruction on configuring a Java agent in the next section)
Note:
The controller listens on port 8090 and 8091. Make sure these ports are not blocked by Firewall.
Controller on Linux requires libaio installed. Also, the number of File Descriptors available should
be at least 65635.
You will need to create two or three user accounts during the install. Remember all the user
names and passwords (especially the root user for the Controller)
Instead of installing the Controller in your local environment, you can choose to use one of
AppDynamics hosted Controller (SaaS based). I suggest on premise to start with so that you get the
real taste of managing the Controller first hand.
Configure your first Java Agent
Installing and Configuring a Java agent is pretty straight forward and simple. You can do this two
ways: Use the ‘Agent download Wizard’ from the controller UI (recommended if this is the first agent
you are configuring), or simply download the agent software from https://download.AppDynamics.com.
Using the Agent download Wizard
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From the Controller UI, click on the ‘Agent Download Tab’. Choose ‘Java’ as the Agent Type
Select JVM
The controller Information is auto populated (this is the advantage of using the wizard)
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Choose or create a new Application
Choose or create Tier
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Your agent is now ready for download
Once you download the Agent (zip or tar file), take the file to the Server you need to instrument and
unzip/untar the file. Now all you have to do is configure your java application to load the agent when it
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starts. The only required configuration is done at the java command line that starts the application.
Simply add the following parameter
-javaagent:AGENT_HOME/javaagent.jar
The Agent log file is at <AGENT_HOME>/logs/<Node name>/agent<date>.log
Using AppDynamics download site
Instead of using the wizard, you may choose to download the agent from AppDynamics website and
manually configure the agent. You can download the agent from https://download.AppDynamics.com.
Once you unzip/untar the agent on the server to be instrumented, all you have to do is update
controller-info.xml and add the java command line parameter to the startup script of your application.
Configure controller-info.xml
This file is found at <AGENT_HOME>/conf/controller-info.xml. Here are the important parameters to be
configured
<controller-host>myServer</controller-host>
<controller-port>8090</controller-port>
<application-name>AcmeShoppingPortal</application-name>
<tier-name>OrderFulfillment</tier-name>
<account-name>***</account-name>
<account-access-key>***</account-access-key>
If you don’t know the account name and access key, check the license page at the controller UI (You
can access the license page by click on the ‘Settings’ button and choosing ‘License’).
Add the following parameter to your Application startup script and restart your application.
-javaagent:AGENT_HOME/javaagent.jar
The Agent log file is at <AGENT_HOME>/logs/<Node name>/agent<date>.log
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Look inside your Java Application, like never before
As soon as you have your Java application reporting to Controller, you can learn a lot about your
application. Some of the things you learn about your application may even be surprising to you.
Appdyanmics automatically creates a flow map of your application. It discovers backends and plots it
for you.
Login to the Controller UI (typically http://<controllerHost>:8080). Navigate to your Application and
Tier if required. A typical application flow may look like the following:
From this point, you can drill down to any of the components to get deeper level metrics.
AppDynamics automatically captures ‘slow response times’ and presents them in ‘Slow response times’
Dashboad from the home page of the Application. Slow response times include remote service calls and
jdbc calls. In addition AppDynamics captures any application ‘errors’ such as a Java Exception or a
HTTP error code and presents them in its own dashboard.
A tremendous feature of AppDynamics is the Transaction snapshot. With a Transaction snapshot, you
can dismantle the transaction down to the code level and see the response time in various subsystems.
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For example, you can clearly see if a transaction is slow because of a DB call or because of a remote
web service call (or because of JVM time itself, which may indicate Garbage Collection or other Memory
issues)
Image Source: www.appdynamics.com
Get alerted before things get worse
AppDynamics automatically learns the application behavior by determining the baseline value for any
metric. When the current value deviates from baseline over a certain limit, it triggers an alert. The
deviation is configurable.
AppDynamics implements alerting using two elements: Health rules and Policies. Health rule is where
you will define the performance metric to monitor and the threshold to watch for. Policy tells
AppDynamics what to do when Health rules are violated. The action could be emailing or paging
someone (or a group), or even executing a program.
AppDynamics come prebuilt with several Default Health Rules. An example is JVM memory utilization
(Heap). You can update the thresholds for these default health rules.
In addition you can create an Email Digest that includes a summary of events over a certain period.
This can be useful item for senior management.
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Image Source: www.appdynamics.com
Monitor your hardware too
With AppDynamics Machine Agent, you can monitor basic metrics such as CPU utilization, Memory
Utilization etc for most of the popular Operating Systems.
Some default Metrics monitored:
CPU Metrics
Disks Metrics
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Machine Metrics
Memory Metrics
Network Metrics
System Metrics
In addition to monitoring the hardware, Machine Agent lets you write your own monitoring programs
and send the data to AppDynamics Controller. This is a very powerful future as it virtually allows you to
monitor anything. These programs are called extensions and there are tons of extensions already
available for download at https://www.appdynamics.com/community/exchange/
Where to go next?
Congratulations on learning what AppDynamics can do for your organization. I have just covered the
tip of iceberg. What you can do with AppDynamics is only up to you. You can take your monitoring to
an entirely different level by leveraging all the features that AppDynamics offers.
I recommend downloading and trying out your own AppDynamics Controller. Install a Java Agent on
one of your test environments and play with it for a while. Start at
https://download.appdynamics.com. For documentation, start at https://docs.appdynamics.com. There
is also a community at http://www.appdynamics.com/community/
AppDynamics offers tons of webminars. Check out the events calendar at
http://www.appdynamics.com/community/events/
Happy Monitoring !!!
