@nicks1993 since it is an index setting, you will need to update the settings.
PUT /my_index/_settings
{
"index" : {
"default_pipeline" : "my_pipeline"
}
}
index.default_pipeline
The default ingest node pipeline for this index. Index requests will fail if the default pipeline is set and the pipeline does not exist. The default may be overridden using thepipelineparameter. The special pipeline name_noneindicates no ingest pipeline should be run.