Introduction

• The JS7 Agent comes preinstalled with a Docker® 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® containers:

Pulling the Agent Image

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

docker image pull sosberlin/js7:agent-2-3-2

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

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

docker image pull sosberlin/js7:agent-2-3-2-plus

Running the Agent Container

After pulling the Agent image you can run the container with a number of options such 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-2-3-2

Explanation:

• --network The above example makes use of a Docker 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® 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 network.
• --publish The Agent is configured to listen to HTTP port 4445 by default. An outside port of the Docker host can be mapped to the Agent's inside HTTP port. This is not required for use with a Docker network, see --network, however, it will allow direct access to the Agent from the Docker 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 for the Agent, e.g. with -Xmx256m.
• --env=RUN_JS_USER_ID Inside the container the Agent is operated with the jobscheduler user account. In order to access files created by the Agent such as log files, and which are mounted to the Docker 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 variable accepts the user ID and group ID of the account that will be mapped. The above example makes use of the current user.
• --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 the operation of the Agent - see the 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, 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 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:
    
    

    Example how to create Docker volumes

    # example to map volumes to directories on the Docker 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-2-0-1: 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-2-0-1-plus for use of a "plus" image.

Time Service

It is recommended that a time service is operated on the docker host which runs the Agent 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.

When mounting a volume for log files as explained above you should have access to the files indicated with the JS7 - Log Files and Locations article.

• 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 such as workflows and jobs is not subject to compliance requirements such as non-repudiation.
• HTTP connections are used 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 in the JS7 - Agent Build for Docker Image article.