covalent-ssh-plugin 0.7.0rc0

Covalent SSH Plugin

Covalent is a Pythonic workflow tool used to execute tasks on advanced computing hardware. This executor plugin interfaces Covalent with other machines accessible to the user over SSH. It is appropriate to use this plugin to distribute tasks to one or more compute backends which are not controlled by a cluster management system, such as computers on a LAN, or even a collection of small-form-factor Linux-based devices such as Raspberry Pis, NVIDIA Jetsons, or Xeon Phi co-processors.

To use this plugin with Covalent, simply install it using pip:

pip install covalent-ssh-plugin

The following shows an example of how a user might modify their Covalent configuration to support this plugin:

[executors.ssh]
username = "user"
hostname = "host.hostname.org"
remote_cache_dir = "/home/user/.cache/covalent"
ssh_key_file = "/home/user/.ssh/id_rsa"
python_path = "/home/centos/miniconda3/envs/my-python-3.8-env/bin/python"

Note that python_path is optional (see below for more information).

This setup assumes the user has the ability to connect to the remote machine using ssh -i /home/user/.ssh/id_rsa user@host.hostname.org and has write-permissions on the remote directory /home/user/.cache/covalent (if it exists) or the closest parent directory (if it does not).

It may be necessary to specify the absolute path to python that you are using if you rely on activating a virtualenv to manage your python dependencies on your remote machine. For example when creating a new conda environment you can explicitly specify the python path by using the python_path configuration option (as above) otherwise it will default to resolving your python installation with which python.

Within a workflow, users can decorate electrons using the default settings:

import covalent as ct

@ct.electron(executor="ssh")
def my_task():
    import socket
    return socket.gethostname()

or use a class object to customize behavior within particular tasks:

executor = ct.executor.SSHExecutor(
    username="user",
    hostname="host2.hostname.org",
    remote_cache_dir="/tmp/covalent",
    ssh_key_file="/home/user/.ssh/host2/id_rsa",
    python_path="/home/centos/miniconda3/envs/my-python-3.8-env/bin/python"
)

@ct.electron(executor=executor)
def my_custom_task(x, y):
    return x + y

For more information on how to get started with Covalent, check out the project homepage and the official documentation.

Release Notes

Release notes are available in the Changelog.

Citation

Please use the following citation in any publications:

W. J. Cunningham, S. K. Radha, F. Hasan, J. Kanem, S. W. Neagle, and S. Sanand. Covalent. Zenodo, 2022. https://doi.org/10.5281/zenodo.5903364

License

Covalent is licensed under the GNU Affero GPL 3.0 License. Covalent may be distributed under other licenses upon request. See the LICENSE file or contact the support team for more details.