You can configure mutual TLS authentication when needed for the endpoints in your Prometheus OpenMetrics integration with New Relic. Add tls_config to your configuration file for Docker, as explained in this example.
Add secret to config file
Recommendation: Put the CA bundle, key, and cert files in a secret, and include them in the Prometheus OpenMetrics integration's container.
Mutual TLS authentication is limited to a static list of URLs. To configure endpoints that require MTLS authentication, follow this example:
targets:  - description: "Secure etcd example"    urls: ["https://123.456.7.1:2379", "https://123.456.7.2:2379"]    tls_config:      ca_file_path: "/etc/etcd/etcd-client-ca.crt"      cert_file_path: "/etc/etcd/etcd-client.crt"      key_file_path: "/etc/etcd/etcd-client.key"transformations:   ...