cortex - config and running issues

[infa-ddeore]

got below issue while installing the chart:

issue 1 :

$ helm install --namespace cortex -n cortex afcharts/cortex -f values.yaml
Error: release cortex failed: Service "cortex-nginx" is invalid: spec.ports[0].nodePort: Forbidden: may not be used when `type` is 'ClusterIP'

fix: removed "nodePort" in stable/cortex/templates/nginx-service.yaml

issue 2:
dns resolver is hardcoded in stable/cortex/templates/nginx-configmap.yaml, it can be added in values.yaml to provide override option, for now I changed "resolver" to my dns name

issue 3:
ruler pod failing with "open /migrations: no such file or directory" error:

$ k -n cortex logs cortex-ruler-6b75b8dc65-2cc9g   
level=info ts=2019-02-28T06:33:23.295079678Z caller=override.go:33 msg="per-tenant overides disabled"
level=info ts=2019-02-28T06:33:23.308854973Z caller=postgres.go:76 msg="running database migrations..."
level=error ts=2019-02-28T06:33:23.314943399Z caller=postgres.go:79 err="open /migrations: no such file or directory"
level=error ts=2019-02-28T06:33:23.31498671Z caller=main.go:97 msg="error initializing rules API" err="database migrations failed"

another pod cortex-config has this dir.

can you suggest what could be the problem, where else can I look?