Knative - Kubernetes Job Trigger

KNative Service for creating kubernetes jobs

PreReq

Please create the below rolebinding to give access to your ksvc to create a job

kubectl apply -f - <<EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: default-rb
  namespace: demo
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: admin
subjects:
- kind: ServiceAccount
  name: default
  namespace: demo
EOF

Creating and Running the service

This knative service looks for the job spec in a environment variable named JOB_SPEC. Below is an example of a service specification

kubectl apply -f - <<EOF
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: sample-job-trigger-svc
  namespace: demo
spec:
  template:
    spec:
      containers:
      - env:
        - name: JOB_SPEC
          value: "{\"Image\": \"murugappans/hw\",\"Name\": \"sample-job\"}"
        image: murugappans/job-trigger:v1
EOF

Configuring your Job

CMD

  "Name": "JOB_SPEC",
  "Value": "{\"Image\": \"murugappans/hw\",\"Name\": \"simplepy\",\"User\": 1002, \"Cmd\": [\"python\", \"job.py\"]}"

Environment Variables

  "Name": "JOB_SPEC",
  "Value": "{\"Image\": \"murugappans/hw\",\"Name\": \"simplego\",\"User\": 1002, \"EnvVariables\": [\"Name\": \"env\",\"Value\": \"prod\"}]}"

CM and Secret volumes

  "Name": "JOB_SPEC",
  "Value": "{\"Image\": \"murugappans/hw\",\"Name\": \"simplego\",\"User\": 1002, \"Secrets\": [{\"Name\": \"secretname\",\"MountPath\": \"pathtomount\"}],\"ConfigMaps\": [{\"Name\": \"cmname\",\"MountPath\": \"pathtomount\"}]}"

CM and Secret as env variables

  "Name": "JOB_SPEC",
  "Value": "{\"Image\": \"murugappans/hw\",\"Name\": \"simplego\",\"User\": 1002, \"EnvFromSecretorCM\": [{\"Name\": \"secretname\",\"Type\": \"Secret\"}]}"

Dynamic input

At run time you might want to inject some variables. Those variables can be passed as url query parameters

For example if the function url is as below. Key and Value will be mounted as environment variable in the job

http://sample-job-trigger.test.com?key=value

Labeling your Job

In some cases you might want to label your job. It can be provided in the query string as below.

http://sample-job-trigger.test.com?labels=label1=value,label2=value

CleanUp

To clean up old jobs, specify the history query parameter. This param specifies the number of job logs to be preseverd.

For example if history is 0, all logs will be will be deleted, for 2 , 2 latest will be preserved.

Default value is 3

http://sample-job-trigger.test.com?history=1