Job Hostnames

Hostnames of Containers that Support Jobs within Workflows

Fuzzball automatically manages hostname resolution within the containers that support jobs. A new subdomain is created for each new workflow, and containers are assigned hostnames corresponding to the name of the jobs they support. Different jobs within a workflow can refer to one another by job name. A longer, Fully Qualified Domain Name (FQDN) is also constructed for each container consisting of the job name, workflows UUID, account UUID, and the domain extension “fuzzball”.

Consider a job within an workflow and account that has the following information.

job name: myjob
workflow UUID: 29344cd9-72a1-426b-a4c9-e724177b7929
account UUID: 3f363570-30d8-4e55-84ec-6046dcca6126

Fuzzball will create a new subdomain for the workflow and assign the following FQDN to the container:

myjob.29344cd9-72a1-426b-a4c9-e724177b7929.3f363570-30d8-4e55-84ec-6046dcca6126.fuzzball

Other jobs within the workflow can use the hostname myjob to resolve the ip address of container.

Hostnames of Task Array and Multinode Jobs

Task array and multinode job hostnames are appended with an integer to distinguish them from one another.

Task array job container hostnames are appended with an integer representing the task ID. So, for instance, a job array with the name myjob that produces a task with FB_TASK_ID=1 will be assigned a hostname of myjob-1.

Multinode job container hostnames are appended with an integer representing the task rank. So, for instance, an MPI job named myjob that supports a task with MPI rank 0 will be assigned a hostname of myjob-0.