Multi docker containers - Using Lagun with UM-Bridge

LAGUN Installation
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The simulation launcher allows to link Lagun to a simulator. To do this, you first need to configure this link to the simulator. Several examples are provided in the Lagun gitlab repository.

In this post, we’ll look at how to link Lagun and Um-bridge, each running within a container.

Step 1 - Create a network

How do you allow one container to talk to another? The answer is networking. If you place the two containers on the same network, they can talk to each other.

https://docs.docker.com/get-started/07_multi_container/

So the first step is to create a network (let’s call it mynetwork). In a command line interpreter, execute the command:

docker network create mynetwork

Step 2 - Start a Um-Bridge model

Let’s start the tsunami model like described in the Um-Bridge documentation. In a command line interpreter, run the model as you normally would, but add two options to specify:

  • the network to connect to;
  • an hostname alias for this container (let’s called it tsunami).
docker run --network mynetwork --network-alias tsunami -it -p 4242:4242 linusseelinger/model-exahype-tsunami

Now the model is running, ready to be called by the simulations launcher.

Step 3 - Customize the Lagun simulator image

In a command line interpreter:

  • Run the simulations launcher image to modify.

    docker run -d detocs/lagun-simulations-launcher:1.1.0-I-b2-alpine

    Should return the id of the run container (for example c49d4120a7a0a62ebe95adc82bb91c92dd12400064be9cc53ac18ffe317c698f).

  • Execute the command to open a shell on this container (replace the id by yours):

    docker exec -it c49d4120a7a0a62ebe95adc82bb91c92dd12400064be9cc53ac18ffe317c698f sh

  • In this shell, execute the command to install the R package umbridge:

    R -e "install.packages('umbridge', repos = 'http://cloud.r-project.org')"

    The installation should end with a line saying DONE (umbridge) (warnings may follow).

  • Modify the simulator configuration file RSimulator.sh dedicated to Um-Bridge in the simulator-examples directory (localhost is to replace by the alias tsunami defined in step 2)

    #!/bin/sh
- Rscript --vanilla lagunClient.R http://localhost:4242 paramFile.txt
+ Rscript --vanilla lagunClient.R http://tsunami:4242 paramFile.txt

  • Exit the shell opened on this container (run the command exit).

  • Commit this container with these changes into a new image (let’s call it launcher-with-umbridge; don’t forget to replace id by yours):

    docker commit c49d4120a7a0a62ebe95adc82bb91c92dd12400064be9cc53ac18ffe317c698f launcher-with-umbridge

Step 4 - Run your modified Simulations Launcher image

In a command line interpreter, run your new image launcher-with-umbridge as you normally would, but add an option to specify the network to connect to:

docker run -dp 0.0.0.0:3000:3000 `
  --network mynetwork `
  --mount type=bind,src="$(pwd)/runningDir",target=/runningDir `
  --mount type=bind,src="$(pwd)/simulator-examples",target=/simulator-examples `
  launcher-with-umbridge

Step 5 - Import the Um-Bridge simulator configuration

Open your simulations launcher client (located by default at http://localhost:3000/) and import the launcher-server-linux.json provided in the simulator-examples directory.

A new simulator called « UM-Bridge » is now available in Lagun!

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