opentelemetry-collector/config/configtls

TLS Configuration Settings

Crypto TLS exposes a variety of settings. Several of these settings are available for configuration within individual receivers or exporters.

Note that mutual TLS (mTLS) is also supported.

TLS / mTLS Configuration

By default, TLS is enabled:

• insecure (default = false): whether to enable client transport security for the exporter's HTTPs or gRPC connection. See grpc.WithInsecure() for gRPC.
• curve_preferences (default = []): specify your curve preferences that will be used in an ECDHE handshake, in preference order. Accepted values are:
  • X25519
  • P521
  • P256
  • P384

As a result, the following parameters are also required:

• cert_file: Path to the TLS cert to use for TLS required connections. Should only be used if insecure is set to false.

  • cert_pem: Alternative to cert_file. Provide the certificate contents as a string instead of a filepath.

• key_file: Path to the TLS key to use for TLS required connections. Should only be used if insecure is set to false.

  • key_pem: Alternative to key_file. Provide the key contents as a string instead of a filepath.

A certificate authority may also need to be defined:

• ca_file: Path to the CA cert. For a client this verifies the server certificate. For a server this verifies client certificates. If empty uses system root CA. Should only be used if insecure is set to false.
  • ca_pem: Alternative to ca_file. Provide the CA cert contents as a string instead of a filepath.

You can also combine defining a certificate authority with the system certificate authorities.

• include_system_ca_certs_pool (default = false): whether to load the system certificate authorities pool alongside the certificate authority.

Additionally you can configure TLS to be enabled but skip verifying the server's certificate chain. This cannot be combined with insecure since insecure won't use TLS at all.

• insecure_skip_verify (default = false): whether to skip verifying the certificate or not.

Minimum and maximum TLS version can be set:

IMPORTANT: TLS 1.0 and 1.1 are deprecated due to known vulnerabilities and should be avoided.

• min_version (default = "1.2"): Minimum acceptable TLS version.

  • options: ["1.0", "1.1", "1.2", "1.3"]

• max_version (default = "" handled by crypto/tls - currently TLS 1.3): Maximum acceptable TLS version.

  • options: ["1.0", "1.1", "1.2", "1.3"]

Explicit cipher suites can be set. If left blank, a safe default list is used. See https://go.dev/src/crypto/tls/cipher_suites.go for a list of supported cipher suites.

• cipher_suites: (default = []): List of cipher suites to use.

Example:

  cipher_suites:
    - TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
    - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
    - TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256

Additionally certificates may be reloaded by setting the below configuration.

• reload_interval (optional) : ReloadInterval specifies the duration after which the certificate will be reloaded. If not set, it will never be reloaded. Accepts a duration string, valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".

How TLS/mTLS is configured depends on whether configuring the client or server. See below for examples.

• tpm (optional): Use the trusted platform module to retrieve the TLS key.

Client Configuration

Exporters leverage client configuration. The TLS configuration parameters are defined under tls, like server configuration.

Beyond TLS configuration, the following setting can optionally be configured:

• server_name_override: If set to a non-empty string, it will override the virtual host name of authority (e.g. :authority header field) in requests (typically used for testing).

Example:

exporters:
  otlp:
    endpoint: myserver.local:55690
    tls:
      insecure: false
      ca_file: server.crt
      cert_file: client.crt
      key_file: client.key
      min_version: "1.1"
      max_version: "1.2"
  otlp/insecure:
    endpoint: myserver.local:55690
    tls:
      insecure: true
  otlp/secure_no_verify:
    endpoint: myserver.local:55690
    tls:
      insecure: false
      insecure_skip_verify: true

Server Configuration

Receivers leverage server configuration.

Beyond TLS configuration, the following setting can optionally be configured (required for mTLS):

• client_ca_file: Path to the TLS cert to use by the server to verify a client certificate. (optional) This sets the ClientCAs and ClientAuth to RequireAndVerifyClientCert in the TLSConfig. Please refer to https://godoc.org/crypto/tls#Config for more information.
• client_ca_file_reload (default = false): Reload the ClientCAs file when it is modified.

Example:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: mysite.local:55690
        tls:
          cert_file: server.crt
          key_file: server.key
  otlp/mtls:
    protocols:
      grpc:
        endpoint: mysite.local:55690
        tls:
          client_ca_file: client.pem
          cert_file: server.crt
          key_file: server.key
  otlp/notls:
    protocols:
      grpc:
        endpoint: mysite.local:55690

Trusted platform module (TPM) configuration

The trusted platform module (TPM) configuration can be used for loading TLS key from TPM. Currently only TSS2 format is supported.

• enabled (default = false): Enables loading tls.key_file from TPM.

• path (default = ""): The path to the TPM device or Unix domain socket. For instance /dev/tpm0 or /dev/tpmrm0. This option is not supported on Windows.

• owner_auth (default = ""): The owner authorization value. This is used to authenticate the TPM device. If not set, the default owner authorization will be used.

• auth (default = ""): The authorization value. This is used to authenticate the TPM device. If not set, the default authorization will be used.

Example:

exporters:
  otlp:
    endpoint: myserver.local:55690
    tls:
      ca_file: ca.crt
      cert_file: client.crt
      key_file: client-tss2.key
      tpm:
        enabled: true
        path: /dev/tpmrm0

The client-tss2.key private key with TSS2 format will be loaded from the TPM device /dev/tpmrm0.