Application Subsystem

Overview

The purpose of the application subsystem is to facilitate easy software delivery and management across all ONOS instances in a cluster. The subsystem uses ONOS eventually consistent map and the inter-node communication mechanism to fully replicate the inventory of applications across the entire ONOS cluster. To install and ignite software as sets of OSGi bundles, the subsystem relies on the underlying Apache Karaf feature mechanism.

All builtin sample and test applications provided by ONOS are now delivered using this mechanism and come pre-installed - although not activated - as part of the standard ONOS distribution. This includes any providers, such as OpenFlow providers. In this way, all optional software components can be installed into and withdrawn from ONOS without the need to rebuild, or even to reconfigure ONOS itself.

Application Package

Applications can be packaged into a single .oar (ONOS Application aRchive) file, for easy delivery of software to a running ONOS cluster. The .oar file is a ZIP file that contains all artifacts, such as feature definitions or OSGi bundles, which may otherwise not be available on Maven central. The following describes the structure of the .oar file:

app.xml - application descriptor
m2/<groupId>/<artifactId>/<version>/<featuresRepo>
m2/<groupId>/<artifactId>/<version>/<artifact>
...

The application package files can be produced using onos-maven-plugin quite easily. The pom.xml file needs to include onos-maven-plugin in its build section and if the pom.xml defines onos.app.name property, or if the module base directory contains app.xml file, the plugin will build the application .oar file and this file will be installed into M2 repository during Maven install phase. See the Maven example below.

Application Definition

Single bundle applications can be easily produced by specifying the following properties in the bundle's pom.xml file:

onos.app.name - name of the application, should be specified in reverse DNS notation, e.g. org.onosproject.fwd
onos.app.origin - name of the originating entity or company, e.g. ON.Lab

Multi-bundle applications, or those that need to bring in other artifacts, or custom feature dependencies can be defined using the app.xml file, located in the module base directory. The app.xml file specifies the following attributes:

name - application name, specified in reverse DNS notation
version - application version
origin - company or organization where application originated
description - short description of the application
features - list of Apache Karaf features that comprise the application
featuresRepo - optional URL of application feature definition artifact
artifact - lists artifacts that are to be included in application package

The following is an example of of the ONOS OnePing sample application app.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<app name="org.onosproject.oneping" origin="ON.Lab" version="1.2.0"
     featuresRepo="mvn:org.onosproject/oneping-app-features/1.2.0-SNAPSHOT/xml/features"
     features="oneping-app,onos-app-tvue">
    <description>One-Ping-Only sample application!</description>
    <artifact>mvn:...</artifact>
</app>

The app.xml file can contain Maven properties such as ${project.groupId}, ${project.artifactId}, ${project.version}, ${project.description}, ${short.version}, which will result in substitution of the appropriate value from the Maven pom.xml file. It is highly recommended to use these in order to minimize the amount of maintenance required.

The ONOS code-base contains examples of both approaches under the apps source tree.

CLI Commands

Administrators can interact with the inventory of applications using the following console commands:

apps - lists all installed applications
app install <mvn-url> ... - installs applications by downloading from the specified URLs
app activate <app-name> ... - activates all specified applications
app deactivate <app-name> ... - deactivates all specified applications
app uninstall <app-name> ... - uninstalls all specified applications

REST API and Shell Utility

Orchestration systems and tools can use the REST API to interact with the application subsystem either directly, or using the onos-app shell utility, which uses the REST API and has the following usage:

onos-app install <app.xml or app.zip> ... - installs application by uploading the specified app.xml or application package file
onos-app install! <app.xml or app.zip> ... - installs and activates applications by uploading the specified app.xml or application package file
onos-app reinstall <app-name> <app.xml or app.zip> ... - re-installs application by uploading the specified app.xml or application package file
onos-app reinstall! <app-name> <app.xml or app.zip> ... - re-installs and activates applications by uploading the specified app.xml or application package file
onos-app activate <app-name> ... - activates the specified application
onos-app deactivate <app-name> ... - deactivates the specified application
onos-app uninstall <app-name> ... - uninstalls the specified application

Maven Example

The following snippet shows the required onos-maven-plugin configuration. ONOS built-in and sample application modules inherit this configuration from the ONOS root pom, but external applications, need to include this configuration in their POM hierarchy or they need to inherit from ONOS root POM:

<plugins>
    ...
    <plugin>
        <groupId>org.onosproject</groupId>
        <artifactId>onos-maven-plugin</artifactId>
        <version>1.4-SNAPSHOT</version>
        <executions>
            <execution>
                <id>app</id>
                <phase>package</phase>
                <goals>
                    <goal>app</goal>
                </goals>
            </execution>
        </executions>
    </plugin>
    ...
</plugins>

Note that the plugin will tag the .oar file as installation artifact, resulting in its installation or deployment into the Maven repository when the Maven install or deploy goals are invoked.

Builtin Sample and Test Applications

The following list describes the inventory of all builtin drivers, providers and the various sample and test applications:

org.onosproject.drivers - Builtin device drivers
org.onosproject.openflow - OpenFlow protocol southbound providers

org.onosproject.bgprouter - BGP router application, features
org.onosproject.config - Network configuration application
org.onosproject.demo - Flow throughput test application
org.onosproject.election - Master election test application
org.onosproject.fwd - Reactive forwarding application using flow subsystem
org.onosproject.intentperf - Intent performance test application
org.onosproject.metrics - Performance metrics collection
org.onosproject.mobility - Host mobility application
org.onosproject.null - Null southbound providers for testing
org.onosproject.optical - Packet/Optical use-case application
org.onosproject.proxyarp - Proxy ARP/NDP application
org.onosproject.sdnip - SDN/IP use-case application

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