kubeletstatsreceiver should verify the server side cert

[a-thaler]

Description
The current metric-agent setup is disabling cert verification of the kubelet (

telemetry-manager/internal/otelcollector/config/metric/agent/receivers.go

Line 39 in b7d18b2

InsecureSkipVerify: true,

)

When reading the docu and comments it should be possible to enable verification using the regular serviceaccount setup (open-telemetry/opentelemetry-helm-charts#1034 (comment))

Enabling the feature on Gardener results in an error message:

{"level":"error","ts":"2025-01-29T15:06:48.572Z","caller":"[email protected]/scraper.go:103","msg":"call to /stats/summary endpoint failed","kind":"receiver","name":"kubeletstats","data_type":"metrics","error":"Get \"https://ip-10-250-0-28.eu-central-1.compute.internal:10250/stats/summary\": tls: failed to verify certificate: x509: certificate signed by unknown authority","stacktrace":"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/kubeletstatsreceiver.(*kubletScraper).scrape\n\tgithub.com/open-telemetry/opentelemetry-collector-contrib/receiver/[email protected]/scraper.go:103\ngo.opentelemetry.io/collector/scraper.ScrapeMetricsFunc.ScrapeMetrics\n\tgo.opentelemetry.io/collector/[email protected]/metrics.go:24\ngo.opentelemetry.io/collector/receiver/scraperhelper.newObsMetrics.func1\n\tgo.opentelemetry.io/collector/[email protected]/scraperhelper/obs_metrics.go:52\ngo.opentelemetry.io/collector/scraper.ScrapeMetricsFunc.ScrapeMetrics\n\tgo.opentelemetry.io/collector/[email protected]/metrics.go:24\ngo.opentelemetry.io/collector/receiver/scraperhelper.(*controller).scrapeMetricsAndReport\n\tgo.opentelemetry.io/collector/[email protected]/scraperhelper/scrapercontroller.go:195\ngo.opentelemetry.io/collector/receiver/scraperhelper.(*controller).startScraping.func1\n\tgo.opentelemetry.io/collector/[email protected]/scraperhelper/scrapercontroller.go:178"}

Please investigate why it is not working on a Gardener cluster.