[frontend] Pipeline generic installation does not include a virtual service

[nakfour]

When installing "platform-agnostic" and trying to get to the pipeline UI from the Kubeflow central dashboard, we get "Sorry, /pipeline/ is not a valid page". Checking for virtualservices in namespace kubeflow, there are none for pipelines. Looking at the code, we dont see a VirtualService created : https://github.com/kubeflow/manifests/tree/master/apps/pipeline/upstream/base/installs/generic
While multi-user install does include a virtualservice: https://github.com/kubeflow/manifests/blob/master/apps/pipeline/upstream/base/installs/multi-user/virtual-service.yaml

[zijianjoy]

Thank you @nakfour for submitting this request!

@Bobgy and I have discussed about this issue and our initial thinking is to perform following refactorings:

1. For ml-pipeline-ui VirtualService, we need to create a folder called ml-pipeline-ui under https://github.com/kubeflow/pipelines/tree/master/manifests/kustomize/base/pipeline, and put all UI related items, including virtual service file there.
2. For metadata-grpc VirtualService, we will create a folder called virtual-service under options folder: https://github.com/kubeflow/pipelines/tree/master/manifests/kustomize/base/metadata/options. And put the virtual service definition to that folder. And put the remaining files under istio option to a new folder called multi-user option. Also we need to add a README to explain that if you want to use virtual service, you can install virtual-service option.

[zijianjoy]

For now, you can use the kubeflow/pipelines instead of kubeflow/manifests repo for the virtual service definition: https://github.com/kubeflow/pipelines/blob/master/manifests/kustomize/base/metadata/options/istio/virtual-service.yaml

[Bobgy]

@zijianjoy virtual service for ml-pipeline-ui should still be put in options folder, because it's not needed for env without istio.

[nakfour]

@Bobgy @zijianjoy sounds good. since these VRs are common for all options to install pipelines, good idea to place them under base/pipeline