Clever Cloud allows you to run WAR or EAR applications. You can deploy these projects without changing your code. We just need a configuration file with your targeted container.

In JEE , application modules are packaged as EAR and WAR based on their purpose.

  • WAR : Web modules which contains Servlet class files, JSP FIles, supporting files, GIF and HTML files are packaged as JAR file with .war extension.

  • EAR : *.war and *.jar files are packaged as JAR file with .ear extension and deployed into Application Server. EAR file contains configuration such as application security role mapping, EJB reference mapping and context root URL mapping of web modules.

Note : like other runtimes, Java application needs to listen on

Available containers

Clever Cloud supports many servlet containers. The supported containers are listed below:

Apache Tomcat 4.1 (TOMCAT4)Jetty 6.1 (JETTY6)Jboss 6.1(JBOSS6)Glassfish 3.1 (GLASSFISH3)Payara 4.1(PAYARA4)Resin 3.1 (RESIN3)WildFly 9.0.2 (WILDFLY9)
Apache Tomcat 5.5 (TOMCAT5)Jetty 7.6 (JETTY7)Jboss AS 7.1 (JBOSS7)Glassfish 4.1 (GLASSFISH4)Payara 5.2022 (PAYARA5)WildFly 17.0.1 (WILDFLY17)
Apache Tomcat 6.0 (TOMCAT6)Jetty 8.1 (JETTY8)Payara 6.2023 (PAYARA6)WildFly 23.0.2 (WILDFLY23)
Apache Tomcat 7.0 (TOMCAT7)Jetty 9.0 (JETTY9)WildFly 24.0.1 (WILDFLY24)
Apache Tomcat 8.8 (TOMCAT8)

Create an application on Clever Cloud

With the web console

Refer to Quickstart for more details on application creation via the console.

With the Clever Tools CLI

  1. Make sure you have clever-tools installed locally or follow our CLI getting started guide.
  2. In your code folder, do clever create --type <type> <app-name> --region <zone> --org <org> where :
    1. type is the type of technology you rely on
    2. app-name the name you want for your application,
    3. zone deployment zone (par for Paris and mtl for Montreal)
    4. org the organization ID the application will be created under.

Refer to clever create for more details on application creation with Clever Tools.

Setting up environment variables on Clever Cloud

With the Clever Cloud console

  1. Go to the Clever Cloud console, and find the app you want to fine tune under it’s organization.
  2. Find the Environment variables menu and select it.
  3. In this menu, you will see a form with VARIABLE_NAME and variable value fields.
  4. Fill them with the desired values then select Add.
  5. Don’t forget to “Update Changes” at the end of the menu.

With the Clever Tools CLI

  1. Make sure you have clever-tools installed locally. Refer to our CLI getting started.
  2. In your code folder, do clever env set <variable-name> <variable-value>

Refer to environment variables reference for more details on available environment variables on Clever Cloud.

You can of course create custom ones with the interface we just demonstrated, they will be available for your application.

Available Java versions

Simply set the environment variable CC_JAVA_VERSION to the version you want.

⚠️ Clever Cloud uses Java version 11 by default. New applications have the CC_JAVA_VERSION environment variable set to 21.

Accepted values are 7, 8, 11, 17, 21, 22 or graalvm-ce (for GraalVM, based on OpenJDK 11.0).

We follow the official Java roadmap by supporting both LTS and latest non-LTS versions.

We are using OpenJDK distribution for mentioned Java versions.

Every non-LTS versions where Premier support ends will be removed without warning as you should be able to switch to the next available non-LTS version without any trouble.

Configure your Java application

You must provide a clevercloud/war.json file in your application repository.

Full configuration example

Here’s what your configuration file can look like:

   "build": {
      "type": "maven",
      "goal": "package"
   "deploy": {
      "container": "TOMCAT8",
      "war": [
            "file": "target/my-app-1.0-SNAPSHOT.war",
            "context": "/app1",
            "checkMe": "/app1/ping"
            "file": "my-second-app.war",
            "context": "/app2",
            "checkMe": "/app2/web/foobar"

Breaking down the configuration


Here are the mandatory fields:

   "deploy": {
      "war": [
            "file": "<string>",
            "context": "/<string>",
            "checkMe": "/<string>"
RequiredcontainerName of the container to use. Should contain one of the values inside parentheses in the containers table (uppercase).
RequiredfileShould contain the path of the war/ear file relative to your application root.
Optionalcontext- Must start with a slash (/), can be “/”
- Defines the base path you want your app to be under. If your app has a /foobar endpoint, it will be available under the /{my-context}/foobar path.
- Not needed for an ear file.
- The default value for a war is the name of the war without the extensions: helloworld-1.0.war will be deployed under the /helloworld-1.0 context.
OptionalcheckMe- This field is recommended.
- A path to GET in order to test if the application is really running.
- By default we will consider that the application is up if the container is up.
- With this option, we will try to GET /{checkMe} for each one of your wars and consider the app down until every single checkMe path that replies a 200.

Let Clever Cloud build your application

The mandatory part alone is enough… if you directly push a dry war file to deploy. You might want to just push your code to Clever Cloud and let us build the app and generate the war.

That you can do, by setting the “build” field object in the war.json file:

  "build": {
    "type": "<string>",
    "goal": "<string>"
Requiredtype- The tool you want to use to build your app.
- Can be “maven”, “gradle”, “sbt” or “ant”
Requiredgoal- The goal you want the tool to execute.
- Basically, for maven, you want to put “package” in here.

Available containers for war.json

Here’s the list of the configuration values for the “container” field in war.json:

GLASSFISH3Use Glassfish 3.x (see https://glassfish.java.net/)
GLASSFISH4Use Glassfish 4.x (see https://glassfish.java.net/)
JBOSS6Use JBoss AS 6.x (see https://www.jboss.org/jbossas)
JBOSS7Use JBoss AS 7.x (see https://www.jboss.org/jbossas)
RESIN3Use Resin AS 3.x (see https://www.caucho.com/resin-3.1/doc/)
RESIN4Use Resin AS 4.x (see https://www.caucho.com/resin-4/doc/)
JETTY6Use Jetty servlet container 6.x (see https://jetty.codehaus.org/jetty/)
JETTY7Use Jetty servlet container 7.x (see https://www.eclipse.org/jetty/)
JETTY8Use Jetty servlet container 8.x (see https://www.eclipse.org/jetty/)
JETTY9Use Jetty servlet container 9.x (see https://www.eclipse.org/jetty/documentation/current/)
TOMCAT4Use Tomcat servlet container 4.x (see https://tomcat.apache.org/)
TOMCAT5Use Tomcat servlet container 5.x (see https://tomcat.apache.org/)
TOMCAT6Use Tomcat servlet container 6.x (see https://tomcat.apache.org/)
TOMCAT7Use Tomcat servlet container 7.x (see https://tomcat.apache.org/)
TOMCAT8Use Tomcat servlet container 8.x (see https://tomcat.apache.org/)
PAYARA4Use Payara servlet container 4.x (see https://www.payara.fish/)
WILDFLY9Use Wildfly servlet container 9.x (see https://wildfly.org/)
WILDFLY17Use Wildfly servlet container 17.x (see https://wildfly.org/)
WILDFLY23Use Wildfly servlet container 23.x (see https://wildfly.org/)

Enable health check during deployment

The healthcheck allows you to limit downtimes. Indeed, you can provide Clever Cloud with paths to check. If these paths return something other than 200, the deployment will fail.

Add one (or several) environment variable as such:




The deployment process checks all paths. All of them must reply with a 200 OK response code.

By default, when no environment variable (for ex: APP_HOME) is defined, the monitoring checks your repository root path /.


Using the path listed above, below are the expected logs:

Response from GET /my/awesome/path is 200
Response from GET /my/other/path is 500
Health check failed:
- GET /my/other/path returned 500.
If the deployment fails after this message, please update your configuration and redeploy.

In this example, the first path is OK, but the second one failed. This gives you a hint on what failed in your application.

Best practice for healthcheck endpoints

To make the most of a healthcheck endpoint, have it check your critical dependencies. For example:

  • execute SELECT 1 + 1; on your database
  • retrieve a specific Cellar file
  • ping a specific IP through a VPN

Custom run command

If you need to run a custom command you can specify it through the CC_RUN_COMMAND environment variable. This will override the default way of running your application.


CC_RUN_COMMAND="java -jar somefile.jar <options>"

Monitor your application with New Relic

You can use New Relic to monitor your application on Clever Cloud.

Please refer to our New Relic documentation to configure it for your application.

Git Deployment on Clever Cloud

You need Git on your computer to deploy via this tool. Here is the official website of Git to get more information: git-scm.com

Setting up your remotes

  1. The “Information” page of your app gives you your Git deployment URL, it looks like this:

    1. git+ssh://git@push.clever-cloud.com/<your_app_id>.git
    2. Copy it in your clipboard
  2. Locally, under your code folder, type in git init to set up a new git repository or skip this step if you already have one

  3. Add the deploy URL with git remote add <name> <your-git-deployment-url>

  4. Add your files via git add <files path> and commit them via git commit -m <your commit message>

  5. Now push your application on Clever Cloud with git push <name> master

Refer to git deployments for more details.

Linking a database or any other add-on to your application

By linking an application to an add-on, the application has the add-on environment variables in its own environment by default.

On add-on creation

Many add-ons do exist on Clever Cloud: refer to the full list and check add-ons dedicated pages for full instructions.

During add-on creation, an Applications screen appears, with a list of your applications. You can toggle the button to Link and click next. If you finish the process of add-on creation, the application is automatically linked to it.

Add-on already exists

In the Clever Cloud console, under the Service Dependencies menu of your application, you can use the Link add-ons dropdown menu to select the name of the add-on you want to link and use the add button to finish the process.

You can also link another application from the same page in the Clever Cloud console, using the Link applications dropdown menu.

More configuration

Need more configuration? To run a script at the end of your deployment? To add your private SSH key to access private dependencies?

Go check the Common configuration page.

You may want to have an advanced usage of your application, in which case we recommend you to read the Administrate documentation section.

If you can’t find something or have a specific need like using a non supported version of a particular software, please reach out to the support.

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