configmap-reload

Utils

Updated on July 27

Configmap-Reload Overview

Secure your stack with a hardened Configmap-Reload image freshly-built by Minimus. Minimus images always include the most up-to-date package version for all packages and dependencies contained in the image.

Configmap-Reload is used to trigger and reload automatically when a Kubernetes ConfigMap is updated.

Try It Out

Take the image for a test run to view usage information:

docker run --rm \
reg.mini.dev/configmap-reload -h

Ready to deploy in Kubernetes?

In this example, we will deploy configmap-reload as a sidecar image along with Prometheus Alertmanager. The configmap-reload sidecar watches the ConfigMap for changes and sends a reload signal to the AlertManager pod.

Step 1: Start Cluster

If you have a cluster to work with, skip this step. Otherwise, start a Minikube cluster. Deployment instructions

Step 2: Download the Custom YAML

Download the deployment file alertmanager-deployment.yaml from the Minimus examples repo:

wget https://raw.githubusercontent.com/minimusio/examples/main/configmap-reload/alertmanager-deployment.yaml

Check that the manifest is set to deploy Minimus images:

kubectl apply -f alertmanager-deployment.yaml --dry-run=client -o yaml | grep image:

Step 3: Deploy configmap-reload with prometheus-alertmanager

Run the command from your project directory to deploy prometheus-alertmanager and configmap-reload:

kubectl apply -f alertmanager-deployment.yaml

Step 4: Check the Pods

Check that the Pods are running:

kubectl get pods -l app=alertmanager
kubectl get configmap alertmanager-config
kubectl get svc alertmanager-service

Step 5: Update ConfigMap

Update a ConfigMap with new values:

kubectl patch configmap alertmanager-config --patch '{"data":{"alertmanager.yml":"global:\n  resolve_timeout: 10m\nroute:\n  receiver: updated-receiver\nreceivers:\n- name: updated-receiver"}}'

Open the logs to view the ConfigMap update:

kubectl logs -f deployment/alertmanager -c configmap-reload

The expected output should look like this:

2025/07/30 13:05:41 config map updated
2025/07/30 13:05:41 performing webhook request (1/1)
2025/07/30 13:05:41 successfully triggered reload

Technical Considerations

The Configmap-Reload image provided by Minimus is a slim, security-hardened alternative to the public image from Docker Hub. The images are largely interchangeable, with a few differences as noted below.

Configmap-Reload built by Minimus:

Runs as non-root by default for a security-first approach that protects against privilege escalation attacks. The public image runs as user 65534.
Drill down on the version specification tab to see the default user, listening ports, entrypoint, volumes, environment variables, etc.

The Payoff

A hardened, minimal image that will remain more secure for the long run and accrue vulnerabilities at a slower rate.

See the risk reduction dashboard for a detailed CVE comparison over the past 30 days.
Review the compliance report to see the default hardening and security configurations for the image.

Terms & Info

Trademark

This catalog is published by Minimus. All product names, logos, and marks, other than those belonging to Minimus, shown are owned by their respective rights holders and appear here only to identify the open source software each image contains. Minimus claims no ownership of those marks and implies no affiliation with, endorsement by, certification by, or sponsorship by any rights holder.

Disclaimer

Images are provided "as-is" without warranty of any kind. "Hardened" refers to the security configuration applied at the time of build and does not constitute a guarantee of ongoing security or absence of vulnerabilities. The free tier is provided without support, SLA, or guaranteed patching timelines. Security updates may be applied to paid subscriptions before or instead of free tier images. By pulling or using any image you agree to our Terms of Use.