Deprecate In-Cluster IstioOperator

[whitneygriffith]

Part of #156

TOC agrees that the In-Cluster IstioOperator is a good candidate for deprecation.

• Remove documentation about "Istio Operator" entirely. Hide commands in istioctl. Pretend it does not exist for all intents and purposes, other than for docs. We can move docs into operator/ or some wiki or point to archives. Add warnings to all istioctl commands using it.
• Provide an alternative solution to In-Cluster IstioOperator
• Announce deprecation

[whitneygriffith]

#44814

[whitneygriffith]

#47838

[ericvn]

Do we have any consensus on this being announced at KubeCon and/or someone planning to do the work? It seems that we are only talking deprecation of the "Istio In-Cluster Operator" and not necessarily its removal in istio/istio#44814. My main concern is what the timeline will look like for when the depreciation will be completed and the in-cluster operator is removed from the code.

[whitneygriffith]

Do we have any consensus on this being announced at KubeCon and/or someone planning to do the work? It seems that we are only talking deprecation of the "Istio In-Cluster Operator" and not necessarily its removal in istio/istio#44814. My main concern is what the timeline will look like for when the depreciation will be completed and the in-cluster operator is removed from the code.

We currently do not have an owner for the work and therefore will revist our deprecation announcement and timeline in the Enhancements Subgroup meeting today.

[howardjohn]

IMO we should do the following for Istio 1.23:

• Formally announce deprecation, with removal for Istio 1.24.
• Provide a documentation for migration. This will be, roughly:

istioctl operator remove --purge # Remove the install, so it will not reconcile anything
kubectl get istiooperator -oyaml > iop.yaml
istioctl install -f iop.yaml

We will mention Helm and Sail operator as alternative paths with no smooth migration path.

In Istio 1.24:

• Remove operator.

[whitneygriffith]

istioctl operator remove --purge # Remove the install, so it will not reconcile anything
kubectl get istiooperator -oyaml > iop.yaml
istioctl install -f iop.yaml

@howardjohn What needs to be done for the istioctl migration story beyond testing the migration path?

[howardjohn]

I suppose just docs + test

[zirain]

I'm sure some users will still want to use it, maybe we can move it out of istio(under Istio-ecosystem/istio-operator or istio-ecosystem/istio-legacy-operator) and people who really want to use it can send pr there?