otel-collector-builder

OpenTelemetry Collector Builder (OCB)

OCB generates and compiles a custom Collector binary from a YAML manifest that lists exactly the components to include. Source of truth: cmd/builder in opentelemetry-collector.

Use OCB when the stock otelcol/otelcol-contrib distributions don't fit: you need a component that ships in no distribution, a private/local component, or a slimmer binary with only the components you run.

This skill covers building the distribution. For configuring individual components, see otel-collector; for writing a new component, see the component-authoring guidance; for generating test traffic against the built binary, see otel-telemetrygen.

Workflow

1. Install OCB at the version matching your target Collector version (see Install).
2. Write the manifest — dist: block plus component lists. Start from the minimal manifest; full key reference in references/manifest.md.
3. Align versions. All core components share one v0.x.0 version, contrib components use the same v0.x.0, and confmap providers use the paired stable v1.y.0. Getting this wrong is the #1 build failure — see Version alignment.
4. Build with ocb --config=builder.yaml (binary is named builder when installed via go install). CI, Docker, multi-arch, and local-component workflows are in references/workflows.md.
5. Verify: run ./dist/<name> validate --config=<collector-config>.yaml, then start it and send test data (otel-telemetrygen skill). If the build fails, see references/troubleshooting.md.

Install

Pick the OCB version equal to the Collector core version you're targeting.

# Release binary (named ocb): https://github.com/open-telemetry/opentelemetry-collector-releases/releases?q=cmd/builder
# Go install (binary is named `builder`, not `ocb`):
go install go.opentelemetry.io/collector/cmd/[email protected]

ocb init (experimental) scaffolds a new distribution repo — manifest, Makefile, sample config, README — in --path (default .).

Minimal manifest

# builder.yaml
dist:
  name: otelcol-custom
  description: Custom OpenTelemetry Collector distribution
  output_path: ./dist
  version: 1.0.0

receivers:
  - gomod: go.opentelemetry.io/collector/receiver/otlpreceiver v0.156.0

processors:
  - gomod: go.opentelemetry.io/collector/processor/batchprocessor v0.156.0

exporters:
  - gomod: go.opentelemetry.io/collector/exporter/otlpexporter v0.156.0
  - gomod: go.opentelemetry.io/collector/exporter/debugexporter v0.156.0

providers:
  - gomod: go.opentelemetry.io/collector/confmap/provider/fileprovider v1.62.0
  - gomod: go.opentelemetry.io/collector/confmap/provider/envprovider v1.62.0

providers: semantics. Omitting the key entirely keeps OCB's built-in default set (env, file, http, https, yaml at the paired stable version). But setting providers: at all replaces that set. The generated Collector defaults conf_resolver.default_uri_scheme to env, so an explicit list without envprovider fails configuration validation unless you set another included provider as the default. Either omit the key, or include envprovider plus every scheme the collector's config will use.

Contrib components use the same list syntax:

processors:
  - gomod: github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor v0.156.0

Version alignment

Two version streams exist and must be paired:

Stream	Modules	Example
v0.x.0	OCB itself, all core components (go.opentelemetry.io/collector/...), all contrib components	v0.156.0
v1.y.0 (stable)	confmap providers (confmap/provider/...), other 1.x modules (pdata, etc.)	v1.62.0

Rules:

• Use the same v0.x.0 for every core and contrib component, matched to the OCB version.
• The paired provider version for a given release is authoritative in that release's embedded default manifest: https://github.com/open-telemetry/opentelemetry-collector/blob/cmd/builder/v0.x.0/cmd/builder/internal/config/default.yaml — check it rather than guessing (for v0.156.0 it is v1.62.0).
• Versions require the v prefix (v0.156.0, not 0.156.0).
• --skip-strict-versioning defaults to true, so mismatches surface as Go module resolution errors, not friendly OCB errors. Align versions up front instead of debugging go mod tidy output.

Build commands and flags

ocb --config=builder.yaml                                  # full build: generate + go mod tidy + compile
ocb --config=builder.yaml --skip-compilation               # generate sources only (two-stage CI)
ocb --config=builder.yaml --skip-generate --skip-get-modules  # compile pre-generated sources untouched

Flag	Default	Purpose
--config	embedded default manifest	Manifest path. With no --config, OCB builds otelcorecol, a minimal test-only distribution.
--skip-generate	false	Don't regenerate Go sources
--skip-compilation	false	Generate sources, don't compile
--skip-get-modules	false	Don't run go mod tidy/downloads. Since v0.154.0 also leaves go.mod unregenerated.
--skip-strict-versioning	true	Set to false to make OCB verify resolved versions against the manifest
--ldflags / --gcflags	—	Extra go build flags
--verbose	false	Log the underlying Go commands

Generated output in output_path: main.go, components.go, main_others.go, main_windows.go, go.mod, go.sum, and the compiled binary named dist.name. By default binaries are stripped (-s -w); set dist.debug_compilation: true for Delve-friendly builds.

Reference files

• references/manifest.md — every manifest key: dist: fields, component spec (gomod/import/name/path), providers, replaces, excludes, conf_resolver, telemetry
• references/workflows.md — local component development, CI two-stage builds, Docker and multi-arch builds, relationship to opentelemetry-collector-releases
• references/troubleshooting.md — version mismatches, module conflicts, CGO, missing providers, runtime failures