configmap-reload-iamguarded

Chainguard Container for configmap-reload-iamguarded

configmap-reload is a simple binary to trigger a reload when Kubernetes ConfigMaps or Secrets, mounted into pods, are updated.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/configmap-reload-iamguarded:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

This is the IAMGuarded variant of configmap-reload, optimized for enhanced security with least-privilege access controls. Key differences from the standard configmap-reload image:

• Custom Installation Path: Binary installed at /opt/iamguarded/configmap-reload/bin/configmap-reload
• Non-Root User: Runs as UID/GID 1001 (non-root) by default for improved security
• PATH Configuration: Custom PATH includes /opt/iamguarded/configmap-reload/bin as the first directory
• Minimal Attack Surface: Built on minimal Chainguard base images with only essential dependencies

Getting Started

The configmap-reload-iamguarded image is a lightweight sidecar container that monitors Kubernetes ConfigMaps and Secrets for changes, automatically triggering application reloads when configuration updates are detected.

Basic Docker Usage

Run configmap-reload to watch a directory and trigger an HTTP webhook on changes:

docker run \
  -v /path/to/config:/config:ro \
  cgr.dev/ORGANIZATION/configmap-reload-iamguarded:latest \
    -webhook-url=http://localhost:8080/reload \
    -volume-dir=/config

Command-Line Options

Common configuration flags:

• -webhook-url: URL to send reload notification (required)
• -volume-dir: Directory to watch for changes (can be specified multiple times)
• -webhook-method: HTTP method for webhook (default: POST)
• -webhook-status-code: Expected successful status code (default: 200)
• -webhook-retries: Number of retry attempts (default: 1)

Helm Chart

This image is designed to work with the IAMGuarded Grafana Alloy Helm chart as a sidecar container.

Configuration

The global.org value is required and specifies your Chainguard organization:

cat > values.yaml <<EOF
global:
  org: ORGANIZATION
EOF

To install the chart, use helm with the values.yaml:

helm upgrade --install grafana-alloy oci://cgr.dev/ORGANIZATION/iamguarded-charts/grafana-alloy \
  --namespace grafana-alloy \
  --create-namespace \
  --values values.yaml

The configmap-reload sidecar is automatically configured within the Grafana Alloy chart to watch for configuration changes and trigger Alloy reloads without requiring pod restarts.

Manual Sidecar Configuration

To use this image as a sidecar in your own deployments:

cat > pod.yaml <<EOF
apiVersion: v1
kind: Pod
metadata:
  name: app-with-fips-reload
spec:
  containers:
  - name: app
    image: cgr.dev/ORGANIZATION/my-app-fips:latest
    volumeMounts:
    - name: config
      mountPath: /etc/app-config

  - name: configmap-reload
    image: cgr.dev/ORGANIZATION/configmap-reload-iamguarded-fips:latest
    args:
      - -webhook-url=http://localhost:8080/-/reload
      - -volume-dir=/etc/app-config
    volumeMounts:
    - name: config
      mountPath: /etc/app-config
      readOnly: true

  volumes:
  - name: config
    configMap:
      name: app-config
EOF

Use Cases

Grafana Alloy (Primary Use Case)

When deployed with Grafana Alloy, configmap-reload watches the Alloy configuration file and triggers a reload when changes are detected, enabling dynamic configuration updates without pod restarts.

Prometheus and Alerting

Can also be used with Prometheus, Alertmanager, and similar applications that support configuration reload endpoints:

# Prometheus
-webhook-url=http://localhost:9090/-/reload

# Alertmanager
-webhook-url=http://localhost:9093/-/reload

Custom Applications

Any application that exposes an HTTP reload endpoint can benefit from automatic configuration reloading.

Monitoring

The sidecar exposes Prometheus metrics on port 9533:

# Access metrics
curl http://localhost:9533/metrics

Metrics include:

• configmap_reload_last_reload_successful: Whether the last reload succeeded
• configmap_reload_last_reload_error_timestamp_seconds: Timestamp of last error
• configmap_reload_success_total: Total successful reloads
• configmap_reload_error_total: Total failed reloads

Documentation and Resources

• configmap-reload GitHub Repository
• Grafana Alloy IAMGuarded Helm Chart
• Kubernetes ConfigMaps Documentation
• Kubernetes Secrets Documentation

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

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