Introduction

• The JS7 Agent comes preinstalled from a container image.
  • The image includes a recent OpenJDK Java LTS release.
  • Users who wish to run JS7 - JavaScript Jobs that require JS7 - Installing Oracle GraalVM should consider to build their own images, see JS7 - Agent Build of Container Image.
• Initial operation for JS7 Agents includes:
  
  • registering the Controller instance(s) and Agents that are used in the job scheduling environment.
  • optionally registering a JS7 - Agent Cluster. 

As an alternative to the instructions from this article users can refer to the JS7 - Agent Installation using Docker Compose article.

Installation Video

This video explains how to install the JS7 Agent for Docker® containersfrom a container image:

Pulling the Agent Image

Pull the version of the Agent container image that corresponds to the JS7 release in use, for example:

docker image pull sosberlin/js7:agent-2-1-15-0

Note: Current releases should be applied as available from https://hub.docker.com/r/sosberlin/js7

Alternatively, "'plus" ' container images are available that include a recent PowerShell environment and the the JS7 - PowerShell Module:

docker image pull sosberlin/js7:agent-2-5-10-1plus

Running the Agent Container

After pulling the Agent image you can run the container with a number of options like thissuch as:

#!/bin/sh

docker run -dit --rm \
      --hostname=js7-agent-primary \
      --network=js7 \
      --publish=16445:4445 \
      --env="RUN_JS_JAVA_OPTIONS=-Xmx256m" \
      --env="RUN_JS_USER_ID=$(id -u $USER):$(id -g $USER)" \
      --mount="type=volume,src=js7-agent-primary-var,dst=/var/sos-berlin.com/js7/agent/var_4445" \
      --name js7-agent-primary \
      sosberlin/js7:agent-2-15-10

Explanation:

• --network The above example makes use of a Docker container network - created, for example, using the command docker network create js7  - to allow network sharing between containers. Note that any inside ports used by Docker containers are visible within a Docker® networkcontainer network. Therefore an Agent running for the inside port 4445 is accessible in conjunction with the container's hostname and the same port within the Docker container network.
• --publish The Agent is prepared configured to listen to the HTTP port 4445 by default. An outside port of the Docker container's host can be mapped to the Agent's inside HTTP port. This is not required for use with a Docker container network, see --network, however, it will allow direct access to the Agent from the Docker container's host via its outside port .
• --env=RUN_JS_JAVA_OPTIONS This allows Java options to be injected into the Agent's container. Preferably this is used to specify memory requirements of for the Agent, e.g. with -Xmx256m.
• --env=RUN_JS_USER_ID Inside the container the Agent is operated with the jobscheduler user account jobscheduler. In order to access e.g. log files created by the Agent that such as log files, and which are mounted to the Docker container's host, it is recommended that you map the account that is starting the container to the jobscheduler account inside the container. The RUN_JS_USER_ID environment environment variable accepts the user User ID and group Group ID of the account that will be mapped. The above example makes use of the current user, for details see JS7 - Running Containers for User Accounts.
• --mount The following volume mounts are suggested:
  • var: This folder works as an entry point to the following sub-folders:
    • config: The configuration folder allows the specification of individual settings for Agent operation, the operation of the Agent - see the chapters sections below and the JS7 - Agent Configuration Items article. Default settings are available on initial operation.
    • logs: In order to have persistent Agent log files they have to be written to a volume that is mounted for the container. Feel free to adjust the volume name from the src attribute, however. However, the value of the dst attribute should not be changed as it reflects the directory hierarchy inside the container.
    • state: The Agent requires a directory for journal information that should also be persistent. The journal is required to restore the state of orders when restarting the Agent.

  • Docker offers Containers offer a number of methods for mounting volumes to containers that include, for example, creating a local folder and mapping the folder to a volume before executing the docker run command listed above:
    
    

    Code Block
    language bash title Example how to create Docker volumes linenumbers true
    # example to map volumes to directories on the Dockercontainer's host prior to running the Agent container mkdir -p /home/sos/js7/js7-agent-primary/var docker volume create --driver local --opt o=bind --opt type=none --opt device="/home/sos/js7/js7-agent-primary/var" js7-agent-primary-var

• sosberlin/js7:agent-2-5-0-1: The name of the base image is the same as that which was previously used with the docker pull command. Alternatively this could be sosberlin/js7:agent-2-5-0-1-plus for use of a "plus" image.

Time Service

It is recommended that a time service is operated on the host which runs the Agent container in order to synchronize the system clock's time.

Log Files

Access to log files is essential to identify problems during installation and operation of containers.

...

• The agent.log file reports general information, warnings and errors.
• The watchdog.log file includes information about automated restarts of the Agent.

Further Resources

Running the Agent Container from a "plus" Image

• See the JS7 - Agent Installation for Docker Containers with "'plus" ' images article.

Manage Agents

• JS7 - Management of Standalone Agents
• JS7 - Management of Agent Clusters

Configure the Agent

Note that it is not necessary to configure the Agent - it runs out-of-the-box. The default configuration specifies that:

• deployment of objects , e.g. such as workflows and jobs , is not subject to compliance requirements such as non-repudiation.
• HTTP connections are used that which expose unencrypted communication between Controller instances and Agent. Authentication is performed by hashed passwords.

Users who intend to operate a compliant and secure job scheduling environment are recommended to familiarize themselves with the JS7 - Agent Configuration for Docker Containers article series.

Build the Agent Image

User who wish to create individual images of the Agent will find instructions with in the JS7 - Agent Build for Docker of Container Image article.