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CANFAR Science Platform Headless Jobs

Please contact us before making use of the 'headless job' support--we are incrementally adding support for batch processing in the science platform.

Create an image

Create an image as per the regular process of making containers available in the platform: Publishing

However, label it as headless in https://images.canfar.net to make it available for headless job launching.

Launch a headless job

For the full details of the job launching API, see this section of the akaha API documentation: https://ws-uv.canfar.net/skaha#!/Session_Management/post_session

All jobs will be run as the calling user. All jobs have the /arc filesystem mounted.

With a publically available Image

Example: overriding the command and providing two arguments:

curl -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session -d "name=headless-test" -d "image=images.canfar.net/skaha/terminal:1.1.2" --data-urlencode "cmd=touch" --data-urlencode "args=/arc/home/majorb/headless-test-1a /arc/home/majorb/headless-test-1b"
With a private Image

Example: overriding the command and providing two arguments:

  1. Obtain your Image Registry secret.
    1. Login to the Harbor Image Registry
    2. In the top right, click on your Username, then click on User Profile.
    3. At the bottom of the User Profile modal dialog, there is a CLI secret field. Click on the Copy icon to copy your secret into the clipboard.
      CLI Secret field
  2. With the CLI secret in your clipboard, create a string with your username and secret, separated by a colon (:), and Base64 Encode it: 
    ENCODED_HEADER=`echo -n "myusername:my-secret" | base64 -i -`
  3. Now use that in the session create command: 
    curl --header "x-skaha-registry-auth: ${ENCODED_HEADER}" -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session -d "name=headless-test" -d "image=images.canfar.net/skaha/terminal:1.1.2" --data-urlencode "cmd=touch" --data-urlencode "args=/arc/home/myusername/headless-test-1a /arc/home/myusername/headless-test-1b"

Note The CLI Secret may need to be periodically refreshed from the Harbor page; simply repeat the process from 1.1 above.

On a successful launch from a public or private image, skaha will return the sessionID on a post (job launch). The job will remain in the system for 1 hour after completion (success or failure).

Job phases: - Pending - Running - Succeeded - Failed - Terminating - Unknown

To view all sessions and jobs: curl -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session

To view a single session or job: curl -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session/<sessionID>

To view logs for session: curl -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session/<sessionID>?view=logs

This shows the complete output (stdout and stderr) for the image for the job.

To view scheduling events for session: curl -E ~/.ssl/cadcproxy.pem https://ws-uv.canfar.net/skaha/v0/session/<sessionID>?view=events

Scheduling events will only be seen when there are issues scheduling the job on a node.

Community and Support

Dicussions of issues and platform features take place in the Science Platform Slack Channel: Science Platform Slack Channel

Reporting of bugs and new feature requests can also be made as github issues: https://github.com/opencadc/skaha/issues

Contributions to the platform (including updates or corrections to the documentation) can be submitted as pull requests to this GitHub repository.

General inquiries can be made to support@canfar.net

FAQ

  • My session is stuck in the Pending state - This can imply that the platform is unable to launch your image. There are a number of potential causes:

  • Often skaha fails to authorize you to https://images.canfar.net due to an expired CLI Secret. Try resetting this value by logging into https://images.canfar.net (using the OIDC Login button), going to your User Profile, and updating your CLI Secret. Once done you should delete the Pending session and try launching it again.

    • If the image is proprietary and the CLI Secret update did not work, check with your project administrator to ensure you have been granted access to the project in https://images.canfar.net
    • The session could be in a Pending state waiting for resources so that it can be scheduled.
    • More information about the reason for the Pending state can be found using the logging mechanisms explained in Programmatic Access.

  • How do I test a graphical container on my Mac?

  • See the instructions to have container display shown on your Mac here: Display ENV on OSX

CANFAR

Last update: November 7, 2024