Understanding Helm Charts

Helm charts are a form of artifacts that serves as a container for numerous images. Make sure the helm chart is valid to assist the artifact scanning.

Vulnerability Scanning Service scans are used for container validation, for more information see Scanning Overview and Vulnerability Reports.

Example values in values.yaml for helm charts are as follows:

oci_meta:
 repo: default.foo.local.io
 images:
    foo:
     image: foo
     tag: 1.1
    bar:
     image: bar
     tag: 1.2

The containers are referred to as follows in the helm chart configuration yaml file:

.....
      containers:
        - name: {{ .Chart.Name }}-xyz
          image: "{{ .Values.oci_meta.repo }}{{ .Values.oci_meta.images.foo.name }}:{{ .Values.oci_meta.images.foo.tag }}"
.....

Validation and Error Codes

Validation scans help to validate the helm charts for formatting related issues. The validation types include the following:

HELM_SYSTEM_ERROR
This is system related message and is displayed when you try to pull up the helm chart.
HELM_LINTER
This message is displayed when you try to run helm provided linter on the chart
HELM_VALUES
This message is regarding values attribute validation and is displayed to refer to the field validation below for details.
HELM_TEMPLATE
This validation is for checking the container references made on template compared to the containers mentioned under oci_meta in values.yaml.

The helm value fields and descriptions are as follows:

oci_meta - Represents presence of attribute on Values.yaml
oci_meta.repo - Represents that the field can be empty or have only ocir.io references.
oci_meta.images - Represents the presence of attribute with one or more entries.
oci_meta.images[*].image - Represents the presence of attribute and is not empty.
oci_meta.images[*].tag - Represents the presence of attribute and is not empty.

A helm chart has bunch of kubernetes configuration file and one or more Values.yaml file. In the kubernetes configuration file you must have the correct references to values.yaml file. The helm templates descriptions are as follows:

Getting the value at containers.image from the chart template spec and checking its presence. Values.oci_meta.
In the kubernetes configuration yaml, the references are present in values.yaml file with the name 'oci_meta'.
Getting the value at containers.image from the chart template spec and it should only refer to as Values.oci_meta.
In the kubernetes configuration yaml, the reference should be only coming from oci_meta.
The images referred in Values.yaml file are presented as part of image map in helm artifact details in Publisher.

HELM ERROR CODES


Error Type	Error Code	Description	Validation	Publisher Error	Guidance
HELM_SYSTEM_ERROR	n/a	Failure to pulling up the helm chart.	n/a	No	n/a
HELM_SYSTEM_ERROR	n/a	Failure in loading the chart.	n/a	No	n/a
HELM_LINTER	HELM_LINTER_ERROR	Helm Linter failed.	Linter	Yes	See Helm Lint for more information.
HELM_VALUES	OCI_META_EMTPY	Absence of oci_meta attr on values.yaml.	Values	Yes	oci_meta attribute on values.yaml is required.
HELM_VALUES	OCI_META_READ_ERROR	Error in reading oci_meta.	Values	Yes	Formatting of oci_meta is incorrect.
HELM_VALUES	OCI_META_REPO_NOT_OCIR	Repository value is not ocir.io.	Values	Yes	Repository is not hosted on ocir.io.
HELM_VALUES	OCI_META_IMAGES_EMPTY	Empty image lists.	Values	Yes	Image list is required.
HELM_VALUES	OCI_META_IMAGES_IMAGE_EMPTY	Empty entry for image.	Values	Yes	Image name entry is empty.
HELM_VALUES	OCI_META_IMAGES_TAG_EMPTY	Empty entry for tag.	Values	Yes	Tag entry is empty.
HELM_TEMPLATE	n/a	Error in parsing template.	Template	Yes/No	The template has to be checked for errors, we try to substitute values.yaml on yaml templates and the cause of this error.
HELM_TEMPLATE	HELM_TEMPLATE_IMAGE_REFERENCES	Image reference mismatch.	Template	Yes	The images referred on yaml templates are not part of images mentioned on oci_meta in values.yaml.

Oracle Cloud Infrastructure Documentation

Understanding Helm Charts

Validation and Error Codes