sentry-uptime-checker

packaged by Chainguard

Chainguard Container for sentry-uptime-checker

Sentry's uptime monitoring service, which runs HTTP checks against monitored URLs and reports the results

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/sentry-uptime-checker:latest

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

Compatibility Notes

Chainguard's sentry-uptime-checker image is comparable to the upstream uptime-checker image that self-hosted Sentry runs (ghcr.io/getsentry/uptime-checker), with the following differences:

• Like upstream, it runs /usr/local/bin/uptime-checker under tini as the app user (UID 1000), with RUST_BACKTRACE=1 and no default command. The binary is also available at /usr/bin/uptime-checker.
• Upstream adds the SSL.com TLS-T-ECC-R2 intermediate certificate to its CA store, because some sites served through Cloudflare do not send it. This image uses the system CA bundle only, so a check against a site that relies on that intermediate can fail with a TLS error. To restore upstream's behavior, mount a CA bundle that includes the intermediate and point SSL_CERT_FILE at it.
• Like other Chainguard Containers, it has a minimal design with no shell or package manager, and it has few to zero CVEs.

Getting Started

The checker reads check configurations from Redis and also serves an API on port 12345 that runs a single check on demand. The following example starts Valkey, an nginx server to monitor, and the checker, then runs an HTTP check against nginx:

docker network create uptime
docker run -d --name valkey --network uptime cgr.dev/ORGANIZATION/valkey:latest
docker run -d --name target --network uptime cgr.dev/ORGANIZATION/nginx:latest

docker run -d --name uptime-checker --network uptime -p 12345:12345 \
  -e UPTIME_CHECKER_REDIS_HOST=redis://valkey:6379 \
  -e UPTIME_CHECKER_PRODUCER_MODE=vector \
  -e UPTIME_CHECKER_ALLOW_INTERNAL_IPS=true \
  cgr.dev/ORGANIZATION/sentry-uptime-checker:latest run

UPTIME_CHECKER_ALLOW_INTERNAL_IPS=true lets the checker reach the nginx container's private address; leave it unset in production so checks cannot probe your internal network. Run the check:

curl -s -X POST -H 'Content-Type: application/json' \
  -d '{"subscription_id": "d7b2c8f0a1e34b5c9d6e7f8091a2b3c4", "interval_seconds": 60, "timeout_ms": 5000, "url": "http://target:8080/"}' \
  http://localhost:12345/execute_config | jq '.check_result | {status, http_status_code: .request_info.http_status_code}'

{
  "status": "success",
  "http_status_code": 200
}

Configuration

In self-hosted Sentry, the checker reads check configurations that Sentry writes to Redis and produces results to Kafka. Run it on the same Docker network as those services. This mirrors the self-hosted configuration:

docker run -d --name uptime-checker --network <sentry-network> \
  -e UPTIME_CHECKER_RESULTS_KAFKA_CLUSTER=kafka:9092 \
  -e UPTIME_CHECKER_REDIS_HOST=redis://redis:6379 \
  -e UPTIME_CHECKER_ALLOW_INTERNAL_IPS=false \
  -e UPTIME_CHECKER_FAILURE_RETRIES=1 \
  cgr.dev/ORGANIZATION/sentry-uptime-checker:latest run

UPTIME_CHECKER_FAILURE_RETRIES sets how many times a failed check is retried before it is reported as failed. To resolve check targets through specific name servers instead of the system resolver, set UPTIME_CHECKER_HTTP_CHECKER_DNS_NAMESERVERS to a comma-separated list.

To use this image in self-hosted Sentry, set UPTIME_CHECKER_IMAGE in your .env file to cgr.dev/ORGANIZATION/sentry-uptime-checker:latest.

Documentation and Resources

• uptime-checker on GitHub
• Self-hosted Sentry documentation
• Uptime Monitoring in Sentry

What are Chainguard Containers?

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• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
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• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

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Need additional packages?

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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.

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Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.