Deploying Java applications¶
Overview¶
This document is a hands-on guide to deploying a simple Java application on tsuru. The example application is a simple mvn generated archetype, in order to generate it, just run:
$ mvn archetype:generate -DgroupId=io.tsuru.javasample -DartifactId=helloweb -DarchetypeArtifactId=maven-archetype-webapp
You can also deploy any other Java application you have on a tsuru server. Another alternative is to just download the code available at GitHub: https://github.com/tsuru/tsuru-java-sample.
Creating the app¶
To create an app, you use the command app create:
$ tsuru app create <app-name> <app-platform>
For Java, the app platform is, guess what, java! Let’s call our application “helloweb”:
$ tsuru app create helloweb java
To list all available platforms, use the command platform list.
You can see all your applications using the command app list:
$ tsuru app list
+-------------+-------------------------+------------------------------+
| Application | Units State Summary | Address |
+-------------+-------------------------+------------------------------+
| helloweb | 0 of 0 units in-service | helloweb.192.168.50.4.nip.io |
+-------------+-------------------------+------------------------------+
Deploying the code¶
Using the Java platform, there are two deployment strategies: users can either
upload WAR files to tsuru or send the code using the regular tsuru app deploy
approach. This guide will cover both approaches:
WAR deployment¶
Using the mvn archetype, generating the WAR is as easy as running mvn
package, then the user can deploy the code using tsuru app deploy:
$ mvn package
$ cd target
$ tsuru app deploy -a helloweb helloweb.war
Uploading files.... ok
---- Building application image ----
---> Sending image to repository (0.00MB)
---> Cleaning up
---- Starting 1 new unit ----
---> Started unit 21c3b6aafa...
---- Binding and checking 1 new units ----
---> Bound and checked unit 21c3b6aafa
---- Adding routes to 1 new units ----
---> Added route to unit 21c3b6aafa
OK
Done! Now you can access your project in the address displayed in the output of
tsuru app list. Remember to add /helloweb/.
You can also deploy you application to the / address, renaming the WAR to ROOT.war and redeploying it:
$ mv helloweb.war ROOT.war
$ tsuru app deploy -a helloweb ROOT.war
Uploading files... ok
---- Building application image ----
---> Sending image to repository (0.00MB)
---> Cleaning up
---- Starting 1 new unit ----
---> Started unit 4d155e805f...
---- Adding routes to 1 new units ----
---> Added route to unit 4d155e805f
---- Removing routes from 1 old units ----
---> Removed route from unit d2811c0801
---- Removing 1 old unit ----
---> Removed old unit 1/1
OK
And now you can access your hello world in the root of the application address!
Deployment¶
For Deployment, we will send the code to tsuru, and compile the classes there. For that, we’re going to use mvn with the Jetty plugin. For doing that, we will need to create a Procfile with the command for starting the application:
$ cat Procfile
web: mvn jetty:run
In order to compile the application classes during deployment, we need also to
add a deployment hook. tsuru parses a file called tsuru.yaml and runs some
build hooks in the deployment phase.
Here is how the file for the helloweb application looks like:
$ cat tsuru.yaml
hooks:
build:
- mvn package
You can just run tsuru app deploy command and your project will be deployed:
$ tsuru app deploy -a helloweb .
tar: Removing leading `/' from member names
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building helloweb Maven Webapp 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
Downloading: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.3/maven-resources-plugin-2.3.pom
Downloaded: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.3/maven-resources-plugin-2.3.pom (5 KB at 6.0 KB/sec)
Downloading: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/12/maven-plugins-12.pom
Downloaded: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/12/maven-plugins-12.pom (12 KB at 35.9 KB/sec)
...
[INFO] Packaging webapp
[INFO] Assembling webapp [helloweb] in [/home/application/current/target/helloweb]
[INFO] Processing war project
[INFO] Copying webapp resources [/home/application/current/src/main/webapp]
[INFO] Webapp assembled in [27 msecs]
[INFO] Building war: /home/application/current/target/helloweb.war
[INFO] WEB-INF/web.xml already added, skipping
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 51.729s
[INFO] Finished at: Tue Nov 11 17:04:05 UTC 2014
[INFO] Final Memory: 8M/19M
[INFO] ------------------------------------------------------------------------
---- Building application image ----
---> Sending image to repository (2.96MB)
---> Cleaning up
---- Starting 1 new unit ----
---> Started unit e71d176232...
---- Adding routes to 1 new units ----
---> Added route to unit e71d176232
---- Removing routes from 1 old units ----
---> Removed route from unit d8a2d14948
---- Removing 1 old unit ----
---> Removed old unit 1/1
OK
Switching between Java versions¶
In the Java platform provided by tsuru, users can use two version of Java: 7
and 8, both provided by Oracle. There’s an environment variable for defining
the Java version you wanna use: JAVA_VERSION. The default behavior of the
platform is to use Java 7, but you can change to Java 8 by running:
$ tsuru env-set -a helloweb JAVA_VERSION=8
---- Setting 1 new environment variables ----
---- Starting 1 new unit ----
---> Started unit d8a2d14948...
---- Adding routes to 1 new units ----
---> Added route to unit d8a2d14948
---- Removing routes from 1 old units ----
---> Removed route from unit 4d155e805f
---- Removing 1 old unit ----
---> Removed old unit 1/1
And… done! No need to run another deployment, your application is now running with Java 8.
Setting memory for application¶
In the Java platform provided by tsuru, users can use units with different plans and each plan may have containers with different amounts of memory. There’s an environment variable for defining the max amount of heap memory (in megabytes) that Java should use: JAVA_MAX_MEMORY ( it’s equal -Xmx). The default value for this environment variable is 128 (it can be different according to your basebuilder).
$ tsuru env-set -a helloweb JAVA_MAX_MEMORY=1024
---- Setting 1 new environment variables ----
---- Starting 1 new unit ----
---> Started unit o5p1k70289...
---- Adding routes to 1 new units ----
---> Added route to unit o5p1k70289
---- Removing routes from 1 old units ----
---> Removed route from unit d8a2d14948
---- Removing 1 old unit ----
---> Removed old unit 1/1
And… done! No need to run another deployment, your application is now running with more memory.
Going further¶
For more information, you can dig into tsuru docs, or read complete instructions of use for the tsuru command.