Docker Compose does not support configs.*.template_driver

Error message

Docker Compose does not support configs.*.template_driver

What it means

`template_driver` on a config tells SwarmKit to run a plugin that templates the config content before delivery (a Swarm-only feature). Compose has no equivalent when it converts configs into bind mounts, so container creation fails with this explicit unsupported-feature error.

Source

Thrown at pkg/compose/create.go:1176

	configsBaseDir := "/"
	for _, config := range s.Configs {
		target := config.Target
		if config.Target == "" {
			target = configsBaseDir + config.Source
		} else if !isAbsTarget(config.Target) {
			target = configsBaseDir + config.Target
		}

		definedConfig := p.Configs[config.Source]
		if definedConfig.External {
			return nil, fmt.Errorf("unsupported external config %s", definedConfig.Name)
		}

		if definedConfig.Driver != "" {
			return nil, errors.New("Docker Compose does not support configs.*.driver") //nolint:staticcheck
		}
		if definedConfig.TemplateDriver != "" {
			return nil, errors.New("Docker Compose does not support configs.*.template_driver") //nolint:staticcheck
		}

		if definedConfig.Environment != "" || definedConfig.Content != "" {
			continue
		}

		if config.UID != "" || config.GID != "" || config.Mode != nil {
			logrus.Warn("config `uid`, `gid` and `mode` are not supported, they will be ignored")
		}

		bindMount, err := buildMount(p, types.ServiceVolumeConfig{
			Type:     types.VolumeTypeBind,
			Source:   definedConfig.File,
			Target:   target,
			ReadOnly: true,
		})
		if err != nil {
			return nil, err

View on GitHub (pinned to ddc4b044b6)

Solutions

Remove `template_driver:` and inline the final content via `content:` (or pre-render the template yourself into a `file:`)
Keep a separate compose file without template drivers for local dev, sharing anchors for the rest
Deploy the stack with `docker stack deploy` where template drivers are supported

Example fix

# before
configs:
  nginx-conf:
    template_driver: golang
    file: ./nginx.tmpl
# after
configs:
  nginx-conf:
    file: ./nginx-rendered.conf

Defensive patterns

Strategy: validation

Validate before calling

python3 - <<'EOF'
import yaml,sys
cfg=yaml.safe_load(open('compose.yaml'))
for n,c in (cfg.get('configs') or {}).items():
    if 'template_driver' in c: sys.exit(f"config {n} uses unsupported template_driver")
print('ok')
EOF

Prevention

Run `docker compose config` in CI to catch unsupported keys early
Pre-render templated configs in your build step instead of relying on Swarm drivers

When it happens

Trigger: Top-level configs entry with `template_driver: <driver>` referenced by a service during `docker compose up`/create.

Common situations: Swarm-style golang-templated configs (e.g. template_driver: golang) reused under compose; stack files ported from Swarm; CI that validates the same file with both engines.

Related errors

AI-assisted analysis of docker/compose@ddc4b044b6 (2026-08-15). Data as JSON: /api/errors/e6af9bf14774d235. Report an issue: GitHub.