Databases Reference
In-Depth Information
CHAPTER 2
Getting Started
In this chapter, we'll create a Storm project and our first Storm topology.
The following assumes that you have at least version 1.6 of the Java
Runtime Environment (JRE) installed. Our recommendation is to use
the JRE provided by Oracle, which can be found at
http://www.java
Operation Modes
Before we start, it's important to understand Storm
operation modes
. There are two
ways to run Storm.
Local Mode
In
Local Mode
, Storm topologies run on the local machine in a single JVM. This mode
is used for development, testing, and debugging because it's the easiest way to see all
topology components working together. In this mode, we can adjust parameters that
enable us to see how our topology runs in different Storm configuration environments.
To run topologies in Local Mode, we'll need to download the Storm development
dependencies, which are all the things that we need to develop and test our topologies.
We'll see how soon, when we create our first Storm project.
Running a topology in Local Mode is similar to running it in a Storm
cluster. However it's important to make sure that all components are
thread safe
, because when they are deployed in
Remote Mode
they may
run in different JVMs or on different physical machines without direct
communication or shared memory.
In all of the examples in this chapter, we'll work in Local Mode.
