nomad/website/source/docs/drivers/java.html.md

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docs	Drivers: Java	docs-drivers-java	The Java task driver is used to run Jars using the JVM.

Java Driver

Name: java

The Java driver is used to execute Java applications packaged into a Java Jar file. The driver currently requires the Jar file be accessbile via HTTP from the Nomad client.

Task Configuration

The java driver supports the following configuration in the job spec:

• jar_source - (Required) The hosted location of the source Jar file. Must be accessible from the Nomad client, via HTTP

• args - (Optional) The argument list for the java command, space seperated.

Client Requirements

The java driver requires Java to be installed and in your systems $PATH. The jar_source must be accessible by the node running Nomad. This can be an internal source, private to your cluster, but it must be reachable by the client over HTTP.

The resource isolation primitives vary by OS.

Client Attributes

The java driver will set the following client attributes:

• driver.java - This will always be set to "1", indicating the driver is available.

Resource Isolation

The resource isolation provided varies by the operating system of the client and the configuration.

On Linux, Nomad will attempt to use cgroups, namespaces, and chroot to isolate the resources of a process. If the Nomad agent is not running as root many of these mechanisms cannot be used.

As a baseline, the task driver will just execute the command with no additional resource isolation if none are available.