[operator] support cutom autocert-certPeriod time by days

[JaredTan95]

As otel-operator matures, the default 365 days will be at risk when users choose to deploy the operator by autoGenerateCert. Therefore, this PR is intended to provide the ability to configure the expiration time.

I performed local verification in the following way:

1. using custom values to install operator-chart, the same with examples/cutstom-autoGenerateCert-period/values.yaml

cd charts/opentelemetry-operator
helm install opentelemetry-operator . -f examples/cutstom-autoGenerateCert-period/values.yaml

manager:
  collectorImage:
    repository: "otel/opentelemetry-collector-k8s"

admissionWebhooks:
  certManager:
    enabled: false
  autoGenerateCert:
    enabled: true
    # If set to true, new webhook key/certificate is generated on helm upgrade.
    recreate: false
    # Cert period time in years. The default is 1(365 days).
    certPeriodDays: 200

3. get tls.cert

kubectl get secret opentelemetry-operator-controller-manager-service-cert -o jsonpath='{.data.tls\.crt}' | base64 --decode > tls.crt

4. use openssl to check the period time of tls.crt

openssl x509 -in tls.crt -noout -dates 

and I got this:

notBefore=Jul  9 02:57:00 2024 GMT
notAfter=Jan 25 02:57:00 2025 GMT # 👈 This is in line with my expectations

[JaredTan95]

sad, https://github.com/open-telemetry/opentelemetry-helm-charts/actions/runs/9841098833/job/27166919581?pr=1249#step:5:200

Since each CI will re-generated cutstom-autoGenerateCert-period example, can not be consistent, remove cutstom-autoGenerateCert-period?

[jaronoff97]

the name of this example should be custom-auto-generate-cert-period IMO

[jaronoff97]

also, do we need to have a full example for setting this single variable?

[JaredTan95]

I think examples/cutstom-autoGenerateCert-period/values.yaml content is the full example

[jaronoff97]

yes, i'm not sure we need to make a whole new full example for this, i was mentioning that the naming with caps is a bit odd here too

[JaredTan95]

sad, https://github.com/open-telemetry/opentelemetry-helm-charts/actions/runs/9841098833/job/27166919581?pr=1249#step:5:200

Since each CI will re-generated cutstom-autoGenerateCert-period example, can not be consistent, remove cutstom-autoGenerateCert-period?

@jaronoff97 hi, any idea about this?

[jaronoff97]

@JaredTan95 what do you get if you run the make generate locally?

[JaredTan95]

every time run ``

@JaredTan95 what do you get if you run the make generate locally?

Similarly, the certificate is regenerated each time with CHARTS=opentelemetry-operator make generate-examples

[jaronoff97]

@JaredTan95 i'll try running locally and see what happens.

[jaronoff97]

@JaredTan95 seems like we have failures here too same thing.

[jaronoff97]

ohhh i see the problem now... hmmm.....

[TylerHelmuth]

Let's not add the new problematic example. The scenario is pretty straight forward (as in the values.yaml file isn't common or interesting) so I don't think we need a new example for it.