Provide guidance on cert-manager

[cyrille-leclerc]

Explain users that the default setup will install self-signed certs with expiration challenges and that cert-manager is recommended in production.

@theSuess do you think we can progress on your great PR:

• feat(opentelemetry-operator): auto detect presence of cert-manager CRDs open-telemetry/opentelemetry-helm-charts#2021

[cyrille-leclerc]

FYI the Amazon EKS addon for OTel recommends installing cert-manager:

https://aws-otel.github.io/docs/getting-started/adot-eks-add-on/requirements#tls-certificate-requirement

[theSuess]

In any case, we should recommend using cert-manager as well, as it's more stable and causes fewer issues in the long run.

Theoretically, we could detect cert manager dynamically, but I really don't want to complicate the installation snippet any further

[cyrille-leclerc]

In any case, we should recommend using cert-manager as well, as it's more stable and causes fewer issues in the long run.

💯 and IMO help practitioners doing a basic install of cert-manager

Theoretically, we could detect cert manager dynamically,

Do you want to continue push your upstream PR? I would be happy to help.

but I really don't want to complicate the installation snippet any further

Do you mean that you think we shouldn't ask people in the GUI if they have cert-manager in place?

[theSuess]

Yeah sorry, didn't formulate this very well: I was considering detecting if the user has cert manager installed and installing it if it's not the case.

If we make cert manager an active choice during our onboarding, we won't actually need the upstream PR as we always know the state at that point