Default behavior of the Subscription regarding major version updates.

[shnoru1]

Feature Request

Is your feature request related to a problem? Please describe.
I had an issue with Keycloak deployment in the morning.
There was a problem when the Keycloak operator was upgraded automatically from version 16.1.0 to version 17.0.0.
After investigation, it was not the problem of Keycloak itself, but there was an incompatibility issue between Keycloak and a third party plugin (keycloak-metrics-spi in my case).
Here is my environment setup.

• operator-lifecycle-manager version:

  / # /bin/olm --version
  OLM version: 0.18.1
  git commit: 02d278ba2d9d884888eb6f8a5ce2f4abdc56e581
  

• Kubernetes version information:

  Server Version: version.Info{Major:"1", Minor:"20+", GitVersion:"v1.20.11-eks-f17b81", GitCommit:"f17b810c9e5a82200d28b6210b458497ddfcf31b", GitTreeState:"clean", BuildDate:"2021-10-15T21:46:21Z", GoVersion:"go1.15.15", Compiler:"gc", Platform:"linux/amd64"}
  

• Kubernetes cluster kind:
  EKS
  The detail of my scenario is as follows.
• I created a Subscription with the following yaml.

  apiVersion: operators.coreos.com/v1alpha1
  kind: Subscription
  metadata:
    name: keycloak-operator
    namespace: keycloak
  spec:
    channel: alpha
    name: keycloak-operator
    source: operatorhubio-catalog
    sourceNamespace: olm

• I deployed a Keycloak instance with the following yaml.

  apiVersion: keycloak.org/v1alpha1
  kind: Keycloak
  metadata:
    name: keycloak
  spec:
    instances: 3
    extensions:
      - >-
        https://github.com/aerogear/keycloak-metrics-spi/releases/download/2.3.1/keycloak-metrics-spi-2.3.1.jar

• New install plans are created and approved automatically by default.

  NAMESPACE   NAME            CSV                         APPROVAL   APPROVED
  keycloak    install-xxxxx   keycloak-operator.v15.1.0   Automatic  true
  keycloak    install-xxxxx   keycloak-operator.v15.1.1   Automatic  true
  keycloak    install-xxxxx   keycloak-operator.v16.0.0   Automatic  true
  keycloak    install-4dcc5   keycloak-operator.v16.1.0   Automatic  true
  keycloak    install-9g7cw   keycloak-operator.v17.0.0   Automatic  true
  

• When the keycloak operator's version is upgraded to 17.0.0, the keycloak-metrics-spi plugin (with version 2.3.1) complained about the method compatibility and made the whole Keycloak deployment crash.
• I removed and re-deployed the Subscription with changes in installPlanApproval and startingCSV to solve compatibility problems.

  apiVersion: operators.coreos.com/v1alpha1
  kind: Subscription
  metadata:
    name: keycloak-operator
    namespace: keycloak
  spec:
    channel: alpha
    name: keycloak-operator
    source: operatorhubio-catalog
    sourceNamespace: olm
    installPlanApproval: Manual
    startingCSV: keycloak-operator.v16.1.0

Describe the solution you'd like
I'd like to suggest the default behavior of the Subscription to upgrade automatically within minor or patch versions but not to major versions.
I think the major versions are considered to have incompatible API changes, and almost all services follow the semver notation with their versions.
I suggest the type of installPlanApproval field be divided to AutomaticPatch, AutomaticMinor, AutomaticMajor, and the original Automatic can be an alias of AutomaticMinor and AutomaticPatch.

[exdx]

Hi @shnoru1,

Thank you for opening this issue -- this feature request makes sense and is a reasonable ask. The default OLM behavior is to move through all versions in the catalog to the latest version based on semver, and this behavior has been standard through all releases of OLM. A feature that limits automatic updates only based on minor or patch versions would be interesting but would have to be opt-in to not break existing OLM users.

That being said, providing more flexible UX for users around installation is part of the goal of developing the new OLM v2 APIs.

[cdjohnson]

An alternative that Keycloak could implement: Add separate channels per major version. Their git repo for this is here.

They could have:

alpha-v15
alpha-v16
alpha-v17
alpha

This gives the consumer the option to PIN to a specific major version, allowing automatic minor and patch upgrades within that major version.

Your subscription would look like this:

apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: keycloak-operator
  namespace: keycloak
spec:
  channel: v16
  name: keycloak-operator
  source: operatorhubio-catalog
  sourceNamespace: olm
  installPlanApproval: Automatic