@Marvin How do I set an annotation on the kubernetes job pods that prefect-worker runs? I am using Prefect 2.x

To set an annotation on the Kubernetes job pods that

prefect-worker

runs in Prefect 2.x, you can modify the Kubernetes job manifest template used by the Prefect Kubernetes worker. Follow these steps: 1. Locate the Kubernetes Job Manifest Template: Modify the default job manifest template used for the worker. You will add your custom annotation here. The template should look something like this:

yaml
   apiVersion: batch/v1
   kind: Job
   metadata:
     labels: "{{ labels }}"
     namespace: "{{ namespace }}"
     generateName: "{{ name }}-"
     annotations:
       my-custom-annotation-key: "my-custom-annotation-value"
   spec:
     ttlSecondsAfterFinished: "{{ finished_job_ttl }}"
     template:
       spec:
         parallelism: 1
         completions: 1
         restartPolicy: Never
         serviceAccountName: "{{ service_account_name }}"
         containers:
         - name: "{{ name }}"
           # other container specs …

2. Configure the Worker: When you start the Kubernetes worker, point it to use this custom template.

bash
   prefect worker start --pool 'my-work-pool' --type kubernetes --job-template /path/to/custom-job-template.yaml

This will ensure that every job pod created by the Kubernetes worker includes your specified annotations. For more details, refer to the Prefect 2.x documentation related to the Kubernetes worker and job templates here: - Prefect Kubernetes Worker Let me know if you need any further assistance!

@Marvin where would this go in the base-job-template JSON file that I pass in to my “prefect work-pool create” command?

To add annotations to your Kubernetes job pods in the

base-job-template

JSON file when creating a work pool, you will need to add the annotations under the

metadata

section of the

job_configuration

part of the template, like this:

json
{
  "job_configuration": {
    "apiVersion": "batch/v1",
    "kind": "Job",
    "metadata": {
      "labels": "{{ labels }}",
      "namespace": "{{ namespace }}",
      "generateName": "{{ name }}-",
      "annotations": {
        "my-custom-annotation-key": "my-custom-annotation-value"
      }
    },
    "spec": {
      "ttlSecondsAfterFinished": "{{ finished_job_ttl }}",
      "template": {
        "spec": {
          "parallelism": 1,
          "completions": 1,
          "restartPolicy": "Never",
          "serviceAccountName": "{{ service_account_name }}",
          "containers": [
            {
              "name": "{{ name }}",
              // other container specs …
            }
          ]
        }
      }
    }
  },
  "variables": {
    "type": "object",
    "properties": {
      "labels": {
        "type": "object"
      },
      "namespace": {
        "type": "string"
      },
      "name": {
        "type": "string"
      },
      "finished_job_ttl": {
        "type": "integer"
      },
      "service_account_name": {
        "type": "string"
      }
    },
    "required": [
      "labels",
      "namespace",
      "name",
      "finished_job_ttl",
      "service_account_name"
    ]
  }
}

In this example configuration: - The

annotations

section within

metadata

is where you add your custom annotations. - You can replace

"my-custom-annotation-key"

and

"my-custom-annotation-value"

with your desired key-value pairs for annotations. After creating or updating your

base-job-template.json

file, you can pass it to the

prefect work-pool create

command like this:

sh
prefect work-pool create --type kubernetes --base-job-template /path/to/base-job-template.json my-work-pool

Or, if you are updating an existing work pool, use:

sh
prefect work-pool update --base-job-template /path/to/base-job-template.json my-work-pool

For more details, you can refer to the Prefect 2.x Work Pools documentation. Let me know if you have any more questions!

@Marvin What is the “backoffLimit” used for in the base job template?

The

backoffLimit

field in a Kubernetes job specification defines the number of retries before considering a job as failed. It sets the maximum number of times the job controller will retry the job if it fails. This setting is particularly useful for handling transient errors that might occur during job execution. Here's an example of how to include

backoffLimit

in your base job template:

json
{
  "job_configuration": {
    "apiVersion": "batch/v1",
    "kind": "Job",
    "metadata": {
      "labels": "{{ labels }}",
      "namespace": "{{ namespace }}",
      "generateName": "{{ name }}-",
      "annotations": {
        "my-custom-annotation-key": "my-custom-annotation-value"
      }
    },
    "spec": {
      "ttlSecondsAfterFinished": "{{ finished_job_ttl }}",
      "backoffLimit": 4,  // Example backoff limit
      "template": {
        "spec": {
          "parallelism": 1,
          "completions": 1,
          "restartPolicy": "Never",
          "serviceAccountName": "{{ service_account_name }}",
          "containers": [
            {
              "name": "{{ name }}",
              // other container specs …
            }
          ]
        }
      }
    }
  },
  "variables": {
    "type": "object",
    "properties": {
      "labels": {
        "type": "object"
      },
      "namespace": {
        "type": "string"
      },
      "name": {
        "type": "string"
      },
      "finished_job_ttl": {
        "type": "integer"
      },
      "service_account_name": {
        "type": "string"
      }
    },
    "required": [
      "labels",
      "namespace",
      "name",
      "finished_job_ttl",
      "service_account_name"
    ]
  }
}

In this example,

"backoffLimit": 4

means that if the job fails, it will be retried up to 4 times before it is marked as failed. For more details and examples, you can refer to the relevant sections in the Prefect 2.x documentation on work pools and Kubernetes job specifications.

@Marvin My annotations do not seem to be applied to the kubernetes job pods that my work pool is running. What could be going wrong?

There could be a few reasons why your annotations are not being applied to the Kubernetes job pods. Here are some common troubleshooting steps: 1. Verify the Job Template: Ensure that your job template is correctly formatted and includes the annotations section. It should look something like this:

json
   {
     "job_configuration": {
       "apiVersion": "batch/v1",
       "kind": "Job",
       "metadata": {
         "labels": "{{ labels }}",
         "namespace": "{{ namespace }}",
         "generateName": "{{ name }}-",
         "annotations": {
           "my-custom-annotation-key": "my-custom-annotation-value"
         }
       },
       "spec": {
         "ttlSecondsAfterFinished": "{{ finished_job_ttl }}",
         "template": {
           "spec": {
             "parallelism": 1,
             "completions": 1,
             "restartPolicy": "Never",
             "serviceAccountName": "{{ service_account_name }}",
             "containers": [
               {
                 "name": "{{ name }}"
                 // other container specs ...
               }
             ]
           }
         }
       }
     },
     "variables": {
       "type": "object",
       "properties": {
         "labels": {
           "type": "object"
         },
         "namespace": {
           "type": "string"
         },
         "name": {
           "type": "string"
         },
         "finished_job_ttl": {
           "type": "integer"
         },
         "service_account_name": {
           "type": "string"
         }
       },
       "required": [
         "labels",
         "namespace",
         "name",
         "finished_job_ttl",
         "service_account_name"
       ]
     }
   }

2. Update the Work Pool: Make sure to update your work pool with the latest job template:

bash
   prefect work-pool update --base-job-template /path/to/base-job-template.json my-work-ppool

3. Inspect the Pods: Check if the pods are created and verify the annotations directly on the Kubernetes pods:

bash
   kubectl describe pod <pod_name> -n <namespace>

4. Check Prefect Worker Logs: Inspect the logs of your Prefect Kubernetes worker for any errors or warnings that might indicate issues with the job templates:

bash
   kubectl logs <prefect-worker-pod> -n <namespace>

5. Validate Variable Substitution: Ensure the variables used in your template (

{{ labels }}

,

{{ namespace }}

, etc.) are correctly defined and provided. If all of the above checks do not resolve the issue, it might help to look into the comprehensive logs for any discrepancies or consider reaching out to the Prefect community and support for more specific guidance. For further reference, here is the Prefect documentation on Work Pools which might provide additional insights. Let me know if you need any more help!

@Marvin My job spec contains my annotations when I run kubectl get job xxx -o yaml, but the pod description does not have these annotations when I run kubectl get pod xxx -o yaml

The discrepancy you're seeing where the annotations exist on the job but not on the pod can happen because the annotations are being set at the job level but not properly propagated to the pods. Kubernetes has specific places where annotations should be applied if you want them to appear on the pod, particularly under the

template.metadata.annotations

field within the job spec. Here’s how you can ensure that your annotations are applied directly to the pods: 1. Update the Job Template: Make sure the annotations are included under the

template.metadata.annotations

section. For example:

json
   {
     "job_configuration": {
       "apiVersion": "batch/v1",
       "kind": "Job",
       "metadata": {
         "labels": "{{ labels }}",
         "namespace": "{{ namespace }}",
         "generateName": "{{ name }}-"
       },
       "spec": {
         "ttlSecondsAfterFinished": "{{ finished_job_ttl }}",
         "template": {
           "metadata": {
             "annotations": {
               "my-custom-annotation-key": "my-custom-annotation-value"
             }
           },
           "spec": {
             "parallelism": 1,
             "completions": 1,
             "restartPolicy": "Never",
             "serviceAccountName": "{{ service_account_name }}",
             "containers": [
               {
                 "name": "{{ name }}",
                 // other container specs ...
               }
             ]
           }
         }
       }
     },
     "variables": {
       "type": "object",
       "properties": {
         "labels": {
           "type": "object"
         },
         "namespace": {
           "type": "string"
         },
         "name": {
           "type": "string"
         },
         "finished_job_ttl": {
           "type": "integer"
         },
         "service_account_name": {
           "type": "string"
         }
       },
       "required": [
         "labels",
         "namespace",
         "name",
         "finished_job_ttl",
         "service_account_name"
       ]
     }
   }

In this updated template, the annotations are placed under

spec.template.metadata.annotations

. This ensures that they are propagated to the pods created by the job. 2. Apply the Updated Template: Make sure to update your work pool with the revised job template:

bash
   prefect work-pool update --base-job-template /path/to/base-job-template.json my-work-pool

3. Inspect the Updated Pods: After deploying your job with the updated template, inspect the pods to verify that the annotations are now present:

bash
   kubectl get pod <pod_name> -o yaml -n <namespace>

By ensuring that the annotations are in the correct section (

template.metadata.annotations

), they should correctly appear on the individual pods created by the Kubernetes job. Let me know if you need any more help!