Allow setting additional operator flags via the Helm chart

[naemono]

closes #6091

What is this change?

Allows setting the following Operator flags via the Helm chart:

• -disable-config-watch
• -ip-family
• -operator-namespace # is set indirectly via .Release.Namespace
• -ubi-only
• -webhook-secret

Notes for review

-operator-namespace isn't allowed to be set directly, but is set indirectly via whatever namespace the Helm chart is installed within {{ .Release.Namespace }}.
-config is not allowed to be set at all, as it doesn't make sense in the context of a Helm chart. (It's used in the statefulset template --config=/conf/eck.yaml.

Testing done

❯ helm upgrade -i elastic-operator . -n elastic-system --create-namespace --set=config.disableConfigWatch=true --set=config.ipFamily=IPv4 --set=config.ubiOnly=true --set=image.tag=2.9.0

❯ kubectl get cm -n elastic-system elastic-operator -o yaml | yq '.data["eck.yaml"]'
log-verbosity: 0
metrics-port: 0
container-registry: docker.elastic.co
max-concurrent-reconciles: 3
ca-cert-validity: 8760h
ca-cert-rotate-before: 24h
cert-validity: 8760h
cert-rotate-before: 24h
disable-config-watch: true
exposed-node-labels: [topology.kubernetes.io/.*,failure-domain.beta.kubernetes.io/.*]
ip-family: IPv4
set-default-security-context: auto-detect
kube-client-timeout: 60s
elasticsearch-client-timeout: 180s
disable-telemetry: false
distribution-channel: helm
validate-storage-class: true
enable-webhook: true
webhook-name: elastic-operator.elastic-system.k8s.elastic.co
webhook-port: 9443
operator-namespace: elastic-system
enable-leader-election: true
elasticsearch-observation-interval: 10s
ubi-only: true

[pebrc]

Default is empty string?

[naemono]

This is coming from manifest-gen which defaults to using the 'elastic-system' namespace when generating yaml from the helm charts.

cloud-on-k8s/hack/manifest-gen/main.go

Line 121 in 20f11e7

cmd.Flags().StringVarP(&generateFlags.OperatorNamespace, "namespace", "n", "elastic-system", "Operator namespace")

And with the addition of operator-namespace: {{ .Release.Namespace }}, this is why it's now defaulting to setting this in the default configuration.

If preferred, I can just remove this from the template, as it really isn't getting us anything.

[pebrc]

Otherwise lgtm

[naemono]

💚 All backports created successfully

Status	Branch	Result
✅	2.10

Questions ?

Please refer to the Backport tool documentation