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# Deploy Dockerized load generators on Linux

This section describes how to run a Dockerized load generator on a Linux distribution.

For supported protocols on Dockerized load generators, see Supported Protocols.

In this topic:

## Prerequisites

Note: The Ubuntu image for the OneLG load generator replaces the previous Ubuntu load generator docker image.

For information on OneLG, seeLoad generators.

- Install Docker on the target machine, along with its dependencies, and set up the target machine environment as required. Currently, only the 64-bit version is supported. For installation details, see the Docker online documentation.

- Obtain the predefined load generator Docker image. Two images are available for Linux: Ubuntu and RHEL.

  Pull the image from the from the relevant page, accessible from the performance testing page (https://hub.docker.com/u/performancetesting) in the Docker hub.

  Use one of the following commands and appropriate <tag version number>, for example, 24.1:

  Ubuntu

  docker pull performancetesting/opentext_onelg_ubuntu:<tag version number>

  RHEL

  podman pull performancetesting/opentext_onelg_rhel:<tag version number>

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## Run a Dockerized load generator using the predefined image

Use the ready-to-use image to run a load generator on Docker for Linux. If you need customization for your container, for example, for proxy servers, see Run a Dockerized load generator using a custom image.

To run the Ubuntu OneLG image, the appropriate environment variable must be included in the run command: `ONELG_FLAVOR=1`

In addition, you can use the following environment variables to enable JMeter and Gatling on the load generator, if required:

- `ENABLE_JMETER`
- `ENABLE_GATLING`

To run a Dockerized load generator:

Run the load generator container using the appropriate command for Ubuntu or RHEL (to enable Gatling or JMeter, include the bold variables).

Check that the <host_port> on the Linux machine is available and allows incoming requests. You specify this port on the Controller side when connecting to this load generator.

- Ubuntu:

  docker run -id -p <host_port>:54345 -e "ONELG_FLAVOR=1" -e "ENABLE_GATLING=1" -e "ENABLE_JMETER=1" --net=host performancetesting/opentext_onelg_ubuntu:<tag version number>

- RHEL:

  podman run -id -p <host_port>:54345 -e "ENABLE_GATLING=1" -e "ENABLE_JMETER=1" performancetesting/opentext_onelg_rhel:<tag version number>

Example using SSH

The following gives a simple C# code example for running multiple load generator containers using SSH. There are container orchestrator tools which do the same, for example, Kubernetes, OpenShift, Docker Swarm.

    using (var client = new SshClient(dockerHost, dockerHostUserName, dockerHostPasswd))
    {
      client.Connect();
      for (int i =0; i > numOfContainers; i++)
      {
    	string command = "docker run -id -p " + lgInitialPort + i) + ":54345 -e "ONELG_FLAVOR=1" --net=host performancetesting/opentext_onelg_ubuntu:<tag version number>";
    	var terminal = client.RunCommand(command);
    	if (terminal.ExistStatus != 0)
    	{
    	throw new Exception("Failed to create new Docker container");
    	}
    	Console.WriteLine("Docker LG with external port" + lgInitialPort + i + "created.");
      }
       client.Disconnect();
    }

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## Run a Dockerized load generator using a custom image

If your environment requires customized settings for running the container, for example for proxy servers, you can follow the procedure below to create a Dockerfile to build a custom image.

Alternatively, you can do the following: Start the container; once it is running, set up the load generator environment variables, then start the load generator manually inside the container.

To create a Dockerfile to run a custom Dockerized load generator:

1. Create a new folder, and within it create a file named dockerfile. Paste the FROM line, plus the required customization lines, into the file, using the appropriate OpenText Professional Performance Engineering version for the <tag version number>.

   For example, for Ubuntu:

   FROM performancetesting/opentext_onelg_ubuntu:<tag version number>
   ENV http_proxy http://my_proxy_name:port

   Note: The above customization example is for a proxy. It defines an environment variable for the proxy server host and port in the target image.

2. Save dockerfile.

3. Open a command line at the dockerfile folder path and run the following command, using the name you want for your custom image:

   Linux-Ubuntu:

   docker build -t <custom image name> .

   RHEL:

   podman build -t <custom image name> .

4. Create a container for each load generator you want to use, by running the following command:

   Ubuntu:

   docker run -id -p <host_port>:54345 -e "ONELG_FLAVOR=1" --net=host <custom image name>

   RHEL:

   podman run -id -p <host_port>:54345 <custom image name>

   If the custom image in step 3 was built with a tag then include it in the command, for example:

   docker run -id -p <host_port>:54345 -e "ONELG_FLAVOR=1" --net=host <custom image name>:<tag version number>

   Note: Check that the <host_port> on the Linux machine is available and allows incoming requests. You specify this port on the Controller side when connecting to this load generator.

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## After running the load generator containers

Add the load generators containers to scenarios. For details, see Configure Dockerized load generators.

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## Tips and guidelines

- Dockerized load generators that are run from the predefined image are not supported when running over a firewall. (Workaround for advanced users: You can develop your own Docker image with MI Listener support.)

- Use `docker ps` to list the containers that are running.

- To stop the load generator service:

  - Use `docker stop <load generator container name or ID>` if you want to reuse the same load generator.

  - Use `docker rm -f <load generator container name or ID>` in order to remove the load generator container.

- The Dockerfile container has an ENTRYPOINT section. The container first runs the commands in ENTRYPOINT. It sets up the environment and then starts the load generator. The command uses a While loop to wait for input, in order to keep the container from exiting. This behavior prevents you from accessing the container while it is running. Make sure to add -i while starting the container; otherwise the While loop will consume an excessive amount of CPU.

- If you need entry into the container, add an argument such as `--entrypoint=/bin/bash` when starting the container. After entering the container, set the load generator environments and start the load generator . You can then switch to the host using CTRL+p and CTRL+q while keeping the container running in the background. To access the container again, use the `docker attach container_id` command.

- To access the host network directly, use `--net=host` in place of `-p <host_port>:54345`. We recommend you use this flag if the AUT generates a lot of network activity.

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See also:

- Install a load generator
- Prepare for installation

https://admhelp.microfocus.com Professional Performance Engineering,VuGen 8942
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