Documentation Grafana Alloy Reference Components otelcol otelcol.extension.jaeger_remote_sampling

otelcol.extension.jaeger_remote_sampling

otelcol.extension.jaeger_remote_sampling serves a specified Jaeger remote sampling document.

You can specify multiple otelcol.extension.jaeger_remote_sampling components by giving them different labels.

Usage

alloy Copy

otelcol.extension.jaeger_remote_sampling "<LABEL>" {
  source {
  }
}

Arguments

otelcol.extension.jaeger_remote_sampling doesn’t support any arguments and is configured fully through inner blocks.

Blocks

You can use the following blocks with otelcol.extension.jaeger_remote_sampling:

The > symbol indicates deeper levels of nesting. For example, grpc > tls refers to a tls block defined inside a grpc block.

source

Required

The source block configures the method of retrieving the Jaeger remote sampling document that’s served by the servers specified in the grpc and http blocks.

The following arguments are supported:

Exactly one of the file argument, content argument or remote block must be specified.

remote

The remote block configures the gRPC client used by the component.

The following arguments are supported:

By default, requests are compressed with Gzip. The compression argument controls which compression mechanism to use. Supported strings are:

• "gzip"
• "zlib"
• "deflate"
• "snappy"
• "zstd"

If you set compression to "none" or an empty string "", the requests aren’t compressed.

The supported values for balancer_name are listed in the gRPC documentation on Load balancing:

• pick_first: Tries to connect to the first address. It uses the address for all RPCs if it connects, or if it fails, it tries the next address and keeps trying until one connection is successful. Because of this, all the RPCs are sent to the same backend.
• round_robin: Connects to all the addresses it sees and sends an RPC to each backend one at a time in order. For example, the first RPC is sent to backend-1, the second RPC is sent to backend-2, and the third RPC is sent to backend-1.

The :authority header in gRPC specifies the host to which the request is being sent. It’s similar to the Host header in HTTP requests. By default, the value for :authority is derived from the endpoint URL used for the gRPC call. Overriding :authority could be useful when routing traffic using a proxy like Envoy, which makes routing decisions based on the value of the :authority header.

An HTTP proxy can be configured through the following environment variables:

• HTTPS_PROXY
• NO_PROXY

The HTTPS_PROXY environment variable specifies a URL to use for proxying requests. Connections to the proxy are established via the HTTP CONNECT method.

The NO_PROXY environment variable is an optional list of comma-separated hostnames for which the HTTPS proxy should not be used. Each hostname can be provided as an IP address (1.2.3.4), an IP address in CIDR notation (1.2.3.4/8), a domain name (example.com), or *. A domain name matches that domain and all subdomains. A domain name with a leading “.” (.example.com) matches subdomains only. NO_PROXY is only read when HTTPS_PROXY is set.

Because otelcol.extension.jaeger_remote_sampling uses gRPC, the configured proxy server must be able to handle and proxy HTTP/2 traffic.

keepalive client

This keepalive block configures keepalive settings for gRPC client connections.

The following arguments are supported:

tls client

This tls block configures TLS settings used for the connection to the gRPC server.

The following arguments are supported:

If the server doesn’t support TLS, you must set the insecure argument to true.

To disable tls for connections to the server, set the insecure argument to true.

If you set reload_interval to "0s", the certificate never reloaded.

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

• ca_pem and ca_file
• cert_pem and cert_file
• key_pem and key_file

If cipher_suites is left blank, a safe default list is used. Refer to the Go TLS documentation for a list of supported cipher suites.

The curve_preferences argument determines the set of elliptic curves to prefer during a handshake in preference order. If not provided, a default list is used. The set of elliptic curves available are X25519, P521, P256, and P384.

http

The http block configures an HTTP server which serves the Jaeger remote sampling document.

The following arguments are supported:

cors

The cors block configures CORS settings for an HTTP server.

The following arguments are supported:

The allowed_headers specifies which headers are acceptable from a CORS request. The following headers are always implicitly allowed:

• Accept
• Accept-Language
• Content-Type
• Content-Language

If allowed_headers includes "*", all headers will be permitted.

tls

The tls block configures TLS settings used for a server. If the tls block isn’t provided, TLS won’t be used for connections to the server.

The following arguments are supported:

If reload_interval is set to "0s", the certificate never reloaded.

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

• ca_pem and ca_file
• cert_pem and cert_file
• key_pem and key_file

If cipher_suites is left blank, a safe default list is used. Refer to the Go Cipher Suites documentation for a list of supported cipher suites.

client_ca_file sets the ClientCA and ClientAuth to RequireAndVerifyClientCert in the TLSConfig. Refer to the Go TLS documentation for more information.

The curve_preferences argument determines the set of elliptic curves to prefer during a handshake in preference order. If not provided, a default list is used. The set of elliptic curves available are X25519, P521, P256, and P384.

grpc

The grpc block configures a gRPC server which serves the Jaeger remote sampling document.

The following arguments are supported:

keepalive

The keepalive block configures keepalive settings for connections to a gRPC server.

keepalive doesn’t support any arguments and is configured fully through inner blocks.

enforcement_policy

The enforcement_policy block configures the keepalive enforcement policy for gRPC servers. The server will close connections from clients that violate the configured policy.

The following arguments are supported:

server_parameters

The server_parameters block controls keepalive and maximum age settings for gRPC servers.

The following arguments are supported:

debug_metrics

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

disable_high_cardinality_metrics is the Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.

Component health

otelcol.extension.jaeger_remote_sampling is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.extension.jaeger_remote_sampling doesn’t expose any component-specific debug information.

Examples

Serve from a file

This example configures the Jaeger remote sampling extension to load a local JSON document and serve it over the default HTTP port of 5778. Currently this configuration style exists for consistency with upstream OpenTelemetry Collector components and may be removed.

alloy Copy

otelcol.extension.jaeger_remote_sampling "example" {
  http {
  }
  source {
    file             = "/path/to/jaeger-sampling.json"
    reload_interval  = "10s"
  }
}

Serve from another component

This example uses the output of a component to determine what sampling rules to serve:

alloy Copy

local.file "sampling" {
  filename  = "/path/to/jaeger-sampling.json"
}

otelcol.extension.jaeger_remote_sampling "example" {
  http {
  }
  source {
    content = local.file.sampling.content
  }
}

Enable authentication

You can use jaeger_remote_sampling to authenticate requests. This allows you to limit access to the sampling document.

alloy Copy

otelcol.extension.jaeger_remote_sampling "default" {
  http {
    auth = otelcol.auth.basic.creds.handler
  }
  grpc {
     auth = otelcol.auth.basic.creds.handler
  }
}

otelcol.auth.basic "creds" {
    username = sys.env("USERNAME")
    password = sys.env("PASSWORD")
}