Is it possible to dictate which kernel to use when creating a Linode with API?

Hello,
Users are unable to specify a kernel to launch with when creating a new Linode. To boot into a desired kernel via the API, you would first have to prevent its initial boot by issuing call with "booted": false, as such (with whatever specific configurations and additional calls you require) —

curl -X POST https://api.linode.com/v4/linode/instances \
-H "Authorization: Bearer $TOKEN" -H "Content-type: application/json" \
-d '{"type": "g6-standard-2", "region": "us-east", "image": "linode/debian9", "root_pass": "$annpl3p@$$w0Rd", "label": "nameoflinode", "booted": false}'

Once this Linode has been created, you can issue a call altering the kernel of the desired configuration.

curl -H "Content-Type: application/json" \
    -H "Authorization: Bearer $TOKEN" \
    -X PUT -d '{
      "kernel": "linode/direct-disk"
    }' \
    https://api.linode.com/v4/linode/instances/$LINODE_ID/configs/$CONFIG_ID

Your Linodes and relevant Configuration ID required for the above command can be gathered from the following calls, respectively:

curl -H "Authorization: Bearer $TOKEN" \
    https://api.linode.com/v4/linode/instances

curl -H "Authorization: Bearer $TOKEN" \
    https://api.linode.com/v4/linode/instances/$LINODE_ID/configs

Once the configuration has been updated with the desired kernel, issue a boot command as featured below, and your Linode will be booted with the desired kernel.

curl -H "Content-Type: application/json" \
    -H "Authorization: Bearer $TOKEN" \
    -X POST \
    https://api.linode.com/v4/linode/instances/$LINODE_ID/boot

More information about each of these calls can be found at our API Documentation.