Configuration

Servers

Since DFControl utilizes a client-server rest-api model, each server will have its own local deamon running, which stores certain server-side items such as pseudopotentials, Environments and Execs.

Make sure that both julia and DFControl are installed on the target remote server before trying to create a connection to it. Also, it is necessary that your ssh keys are registered on the remote so that no passwords are required for ssh connections.

To up a new Server, in this case with name = "daint" an interactive menu can be called like:

Server("daint")

This will set up all the required information and store it for later use. To start a Server simply call start(server), which will launch the daemon externally. Make sure that the host address points to a persistent server, i.e. if a cluster has multiple frontend nodes, find the ip address of one particular one, and set that one as the host address. During the setup of an external server, it may ask whether a local_tunnel should be created. If enabled, a persistent ssh tunnel will be created from the local machine to the target host through which the http requests will be sent. This is useful when the remote is behind an authentication firewall.

To reconfigure a Server you can always do:

s = Server("daint")
s.root_jobdir = "<where you want jobs to be saved>"
save(s)

If a Server was running first stop it using kill(server).

Pseudopotentials

Pseudopotentials are grouped in sets, which are stored for later ease of use. They can be set up using the configure_pseudoset function.

configure_pseudoset(local_server(), "set_name", "/dir/to/pseudos")

This will go through the specified directories and find files that follow the naming convention element.x_y_z.xyz e.g. Si.pbesol-n-kjpaw_psl.0.1.UPF or si.pbesol-n-kjpaw_psl.0.1.UPF. If multiple are found, all will be stored and the required one can be later specified.

The pseudos will remain on the server where they are stored, and can be listed using list_pseudosets. See Pseudo Potentials for further usage details.

configure_pseudoset(set_name::String, dir::String)

Environments

Environments specify the skeleton of the job script, i.e. which environment variables need to be set, which scheduler flags, etc. Here we will set up an environment and save it on the local Server. Change the information according to your own setup.

e = Environment(name="default", parallel_exec=Exec(exec="mpirun", flags=Dict("-np"=> 4), directives=Dict("N" => 1, "partition" => "parallel"), exports=Dict("OMP_NUM_THREADS"=>1)))
save(local_server(), e)

Execs

An Exec embodies an executable as the name suggests. They hold both the executable, directory and modules required to run the executable. Similar to Environments, they are stored on the server for later use. When storing it is verified that they are able to run.

e = Exec(name="pw", exec="pw.x", dir="/home/user/Softare/qe/bin", modules = ["intel", "intel-mpi", "intel-mkl"])
save(local_server(), e)

Loading/Saving

As shown above there are three main methods related to storing and retrieving data i.e.:

load(server::Server, j::Job)

save(job::Job)

After completing this configuration, it is suggested to look at the (Basic Usage)[@ref] for an introduction to the basic usage of DFControl.