no sampling strategy provider specified, expecting 'adaptive

Error message

no sampling strategy provider specified, expecting 'adaptive' or 'file'

What it means

errNoProvider is returned by Config.Validate in the remote sampling extension when neither the 'adaptive' nor the 'file' sampling strategy provider is configured. The extension must know which strategy source to serve to clients, so an empty provider section is a configuration error.

Source

Thrown at cmd/jaeger/internal/extension/remotesampling/config.go:21

package remotesampling

import (
	"errors"
	"time"

	"github.com/asaskevich/govalidator"
	"go.opentelemetry.io/collector/component"
	"go.opentelemetry.io/collector/config/configgrpc"
	"go.opentelemetry.io/collector/config/confighttp"
	"go.opentelemetry.io/collector/config/configoptional"
	"go.opentelemetry.io/collector/confmap"

	"github.com/jaegertracing/jaeger/internal/sampling/samplingstrategy/adaptive"
)

var (
	errNoProvider        = errors.New("no sampling strategy provider specified, expecting 'adaptive' or 'file'")
	errMultipleProviders = errors.New("only one sampling strategy provider can be specified, 'adaptive' or 'file'")
	errNegativeInterval  = errors.New("reload interval must be a positive value, or zero to disable automatic reloading")
)

var (
	_ component.Config  = (*Config)(nil)
	_ confmap.Validator = (*Config)(nil)
)

type Config struct {
	File     configoptional.Optional[FileConfig]              `mapstructure:"file"`
	Adaptive configoptional.Optional[AdaptiveConfig]          `mapstructure:"adaptive"`
	HTTP     configoptional.Optional[confighttp.ServerConfig] `mapstructure:"http"`
	GRPC     configoptional.Optional[configgrpc.ServerConfig] `mapstructure:"grpc"`
}

type FileConfig struct {
	// File specifies a local file as the source of sampling strategies.

View on GitHub (pinned to 806f444784)

Solutions

Add either a 'file:' block (with the strategy file path) or an 'adaptive:' block to the remotesampling extension config
If you don't need remote sampling, remove the remotesampling extension from the service extensions list and its reference from the pipelines extensions
Run `jaeger validate` or your collector config validator before deploying to catch this at startup config time

Example fix

// before
extensions:
  remote_sampling:
    http:
      endpoint: 0.0.0.0:5778
// after
extensions:
  remote_sampling:
    file:
      path: /etc/jaeger/sampling.json
    http:
      endpoint: 0.0.0.0:5778

Defensive patterns

Strategy: validation

Validate before calling

// validate config before starting the extension
cfg := &remotesampling.Config{}
if cfg.Adaptive == nil && cfg.File == nil {
    return fmt.Errorf("remotesampling requires either 'adaptive' or 'file' provider")
}
if err := cfg.Validate(); err != nil {
    return err
}

Type guard

func hasProvider(cfg *remotesampling.Config) bool {
    return cfg.Adaptive != nil || cfg.File != nil
}

Try / catch

if err := ext.Start(ctx, host); err != nil {
    if strings.Contains(err.Error(), "no sampling strategy provider specified") {
        return fmt.Errorf("fix remotesampling config: %w", err)
    }
    return err
}

Prevention

Always define exactly one of adaptive/file in the remotesampling extension config
Validate collector configs in CI before deployment
Use config templates that default to the file provider

When it happens

Trigger: Starting the jaeger collector extension with remotesampling config where both 'adaptive' and 'file' blocks are absent or empty; Validate() checks exactly one provider is set and fails if zero are.

Common situations: Deploying the OTLP-based jaeger binary with a remotesampling extension stanza that only sets http/server config but omits the provider; copying an example config and deleting the file block; upgrading from an older config format that put the provider elsewhere.

Understand the failure class

Background: "X is required", "must be set", "cannot be empty": the missing-required-config error family, from Vertex AI project/location to WeChat keys — this error's family across 18 libraries.

Related errors

AI-assisted analysis of jaegertracing/jaeger@806f444784 (2026-09-01). Data as JSON: /api/errors/f035a99a9fe1d3a2. Report an issue: GitHub.