PR up at https://github.com/openshift/origin/pull/18517

3.9.3 doesn't have the fix, will check in v3.9.4 when it's ready to test

Issue 1: Should support --initial flag(don't report error unknown flag: --initial)in step4

Issue 2: migrate legacy HPAs should not bring more errors

Above was checked on # oc version
oc v3.9.4
kubernetes v1.9.1+a0ce1bc657
features: Basic-Auth GSSAPI Kerberos SPNEGO

Server <server>
openshift v3.9.4
kubernetes v1.9.1+a0ce1bc657

Issue 1: no it shouldn't, the helptext is incorrect.  Will put PR up for that.
Issue 2: Nothing's broken, except the object graph library: https://github.com/openshift/origin/blob/master/pkg/oc/graph/kubegraph/edges.go#L254-L266.  Hardcoding things is rarely the right thing to do.

At any rate, https://github.com/openshift/origin/pull/18926 fixes issue 1, and issue 2 needs a fix to the graph library, but it's not a bug in the migrate command AFAICT.

Validation steps should actually check that the HPA is working and has the correct scale target ref, not *just* that `oc status` doesn't complain.

filed https://github.com/openshift/origin/issues/18927 for issue 2

Thanks Solly, I checked the autoscaling function works well despite of the errors in "oc status".

I would wait PR 18926 merged to verify this bug

For "oc status" issue, I think I should open a separate bug to track, WDYT?

short-term fix for `oc status` up at https://github.com/openshift/origin/pull/18950
bug to track `oc status`: https://github.com/openshift/origin/issues/18927

bug 1554624 was opened to track the "oc status" fix in https://github.com/openshift/origin/issues/18927 because issue are hard to track for release and easily missed.

Per Derek, Solly's fixes will be reviewed and applied in 3.9.z.

Note to QE:

Read https://bugzilla.redhat.com/show_bug.cgi?id=1543043#c10 for guidance on verifying this.

I'm moving https://github.com/openshift/origin/pull/18926 to fix the cosmetic issue in the 'migrate legacy-hpa' subcommand help but is not part of the verification of this bug.

Tested on OCP v3.10.0-0.58.0
Prepare dc, deployment, RS, rc, and create hpa for each resource from web console seprately
Checked that "oc status" has no error about hpa scale ref now.
Here is the resource apiversion and hpa ref apiversion, including before migrating and after migrating.
1.For dc
$ oc get dc myrundc -o yaml |grep apiVersion -A 2
apiVersion: apps.openshift.io/v1
kind: DeploymentConfig
metadata:
Before migrating:
$ oc get hpa myrundc -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: v1
    kind: DeploymentConfig
    name: myrundc
After migrating:
$ oc get hpa myrundc -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: apps.openshift.io/v1
    kind: DeploymentConfig
    name: myrundc

2.For deployment
$ oc get deployment hello-openshift -o yaml |grep apiVersion -A 2
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
Before migrating:
$ oc get hpa hello-openshift -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: hello-openshift
After migrating:
$ oc get hpa hello-openshift -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: hello-openshift

3.For RS
$ oc get rs frontend -o yaml |grep apiVersion -A 2
apiVersion: extensions/v1beta1
kind: ReplicaSet
metadata:
Before migrating:
$ oc get hpa frontend -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: ReplicaSet
    name: frontend
After migrating:
$ oc get hpa frontend -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: apps/v1
    kind: ReplicaSet
    name: frontend

4.For rc
$ oc get rc myrunrc -o yaml |grep apiVersion -A 2
apiVersion: v1
kind: ReplicationController
metadata:
Before migrating:
$ oc get hpa myrunrc -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: v1
    kind: ReplicationController
    name: myrunrc
After migrating:
$ oc get hpa myrunrc -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: v1
    kind: ReplicationController
    name: myrunrc

Are these the expected results?

Yep, those are expected.  In general (at the moment):

- anything from OpenShift itself (/oapi) should be migrated to aggregated API version (e.g. `v1.DeploymentConfig` --> `apps.openshift.io/v1.DeploymentConfig`)

- anything in `extensions` (e.g. `extensions/v1beta1.ReplicaSet`) should be migrated to the proper equivalent in a non-extensions API group (e.g. `apps/v1.ReplicaSet`)

- anything with a completely incorrect group-version should be fixed (e.g. `extensions/v1beta1.DeploymentConfig`)

- anything else stays the same

When create app from image, and set hpa at the same time, on the page "/create/fromimage?", after creation, the hpa has incorrect ref apiversion and could not word normally:
$ oc get hpa pytest -o yaml |grep scaleTargetRef -A 3
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: DeploymentConfig
    name: pytest
$ oc get hpa
pytest                 DeploymentConfig/pytest           <unknown>/18%   1         4         0          1m

Check on the events page, there is warning info:
pytest 	Horizontal Pod Autoscaler 	Warning 	Failed Get Scale  	no matches for kind "DeploymentConfig" in group "extensions"

That's not a bug with this code.  That's a bug with the dashboard.  Please track that against the dashboard, and verify this bug if migrate works.

According Comment 20 and Comment 21, the migrate works well, will verify this bug, and move issue in Comment 22 in a separate bug.