Restoring init container support.

[rachitchauhan43]

Signed-off-by: rachitchauhan43 rachitchauhan43@gmail.com

What this PR does / why we need it:
Use cases are:

1. In case of Inference graphs, we need to make calls to external services from within a pre/post-process method and for that we need to construct auth headers using secrets loaded by init-container.
2. Similarly, there is a use case where have sensitive data that needs to be decrypted first inside predict method using secret loaded using init container.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #2139

Type of changes
Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Feature/Issue validation/testing:

Please describe the tests that you ran to verify your changes and relevent result summary. Provide instructions so it can be reproduced.
Please also list any relevant details for your test configuration.

• Test A

• Test B

• Logs

Special notes for your reviewer:

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Checklist:

• Have you added unit/e2e tests that prove your fix is effective or that this feature works?
• Has code been commented, particularly in hard-to-understand areas?
• Have you made corresponding changes to the documentation?

Release note:

[rachitchauhan43]

/cc @yuzisun

[rachitchauhan43]

How I tested ?

Used this yaml for ISVC:

kind: InferenceService
metadata:
  name: test-init-container
  namespace: kserve-test
spec:
  predictor:
    volumes:
      - emptyDir: { }
        name: shared-data
    initContainers:
      - image: docker.myorg.com/data-mlplatform/utils/secret-loader:latest
        name: secrets-loader
        volumeMounts:
          - mountPath: /secrets
            name: shared-data
        command: [ 'sh',
                   '-c',
                   'date > /secrets/my-value' ]
    containers:
      - args:
          - --model_name
          - qbo-in
        image: docker.myorg.com/personal/myuser/qbo-in:v1
        name: kserve-container
        volumeMounts:
          - mountPath: /secrets
            name: shared-data
        resources:
          requests:
            cpu: 101m
            memory: 256Mi

As you can see below, i ssh into container and can see my secrets mounted:

See the finally YAML with status and spec both:

isvc_with_initcontainer_yaml.txt

[yuzisun]

Thanks @rachitchauhan43 ! I will re-generate the swagger json later and updated the doc for the process of code-gen.
/lgtm
/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: rachitchauhan43, yuzisun

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[rachitchauhan43]

Thanks @rachitchauhan43 ! I will re-generate the swagger json later and updated the doc for the process of code-gen. /lgtm /approve

@yuzisun: Can you point me where you updated the doc for the process of code-gen ?

[yuzisun]

Thanks @rachitchauhan43 ! I will re-generate the swagger json later and updated the doc for the process of code-gen. /lgtm /approve

@yuzisun: Can you point me where you updated the doc for the process of code-gen ?

It is here in the developer guide https://kserve.github.io/website/master/developer/developer/#iterating