Monitoring Gradle Build Infrastructure with Vigilmon: CI Health, Artifact Repos, Build Time Alerts & SSL

Gradle powers JVM builds for millions of developers — compiling Java, Kotlin, Groovy, and Android projects, running tests, and publishing artifacts to registries. When Gradle's supporting infrastructure goes down, the entire engineering pipeline stalls: developers can't compile locally (if they depend on remote artifact caches), CI pipelines fail to resolve dependencies, and releases stop. Vigilmon gives you external visibility into the infrastructure Gradle depends on — artifact repositories, Gradle Enterprise (Develocity), CI runners, and build cache servers — so you catch failures before build queues pile up.

What You'll Build

• A monitor on your artifact repository (Nexus or Artifactory) to catch dependency resolution failures
• A monitor on Gradle Enterprise (Develocity) for build scan and cache availability
• A TCP check on your remote build cache server
• SSL certificate monitoring for your Gradle infrastructure domains
• Alerting that distinguishes artifact cache misses from full infrastructure outages

Prerequisites

• A Gradle project (version 7.x or 8.x) using remote artifact repositories or Gradle Enterprise
• At minimum one of: Nexus, Artifactory, or Gradle Enterprise running in your infrastructure
• A domain for each service (e.g., https://nexus.example.com, https://ge.example.com)
• A free account at vigilmon.online

Step 1: Verify Your Artifact Repository Health Endpoint

Gradle downloads dependencies from Maven repositories — Nexus, Artifactory, or Maven Central proxies. If the repository is down, every ./gradlew build that needs to resolve a new dependency fails with a network error.

Nexus Repository Manager exposes a health check endpoint:

# Nexus 3.x health check
curl -I https://nexus.example.com/service/rest/v1/status

# Returns 200 OK when Nexus is healthy
# Returns 503 when Nexus is starting or degraded

Artifactory exposes its own health endpoint:

# Artifactory health check
curl -I https://artifactory.example.com/artifactory/api/system/ping

# Returns 200 with body "OK" when healthy

Test your endpoint before configuring Vigilmon. If your artifact repository requires authentication for the health check, add credentials to the request header.

Step 2: Monitor the Artifact Repository with Vigilmon

1. Log in to Vigilmon → Add Monitor → HTTP.
2. URL: https://nexus.example.com/service/rest/v1/status (or your Artifactory ping URL).
3. Check interval: 60 seconds.
4. Response timeout: 15 seconds (artifact repositories can be slow under heavy indexing load).
5. Expected status: 200.
6. Keyword: {"status":"available"} for Nexus, or OK for Artifactory.
7. Label: Gradle artifact repository.
8. Click Save.

This monitor catches:

• Nexus or Artifactory process crashes or JVM OOM kills
• Database backend failures that prevent artifact resolution
• Disk space exhaustion on the artifact storage volume
• Corrupted repository indices that prevent metadata lookups

Alert sensitivity: Set to 2 consecutive failures. Artifact repositories occasionally return transient errors during index rebuilds; two consecutive failures reliably signal an outage that will block builds.

Step 3: Monitor Gradle Enterprise (Develocity)

Gradle Enterprise (now rebranded as Develocity) provides build scans, remote build caching, and predictive test selection. When it's down, remote build caches become unavailable — Gradle falls back to local builds, dramatically increasing CI build times without any explicit error.

Develocity exposes a status endpoint:

curl https://ge.example.com/api/builds?maxBuilds=1
# Returns 200 with JSON when Develocity is serving the API

curl https://ge.example.com/health
# Returns system health status

1. Add Monitor → HTTP.
2. URL: https://ge.example.com/health.
3. Check interval: 2 minutes.
4. Response timeout: 10 seconds.
5. Expected status: 200.
6. Label: Gradle Enterprise / Develocity health.
7. Click Save.

Gradle Enterprise Cloud: If you use Develocity as a SaaS (hosted by Gradle), you don't need to monitor the server itself — but you should still monitor whether your CI can reach it. Create an HTTP monitor for https://api.develocity.gradle.com/api/auth/token which returns 401 when the service is reachable.

When the Develocity monitor fires, your CI builds won't fail immediately — they'll silently fall back to local caching. Build times can quadruple without developers noticing. Catching this early prevents CI slowdowns from cascading into missed SLAs.

Step 4: Monitor the Remote Build Cache Server

Gradle's remote build cache stores task outputs that can be reused across builds and machines. If you run a self-hosted Gradle Build Cache Node (or an HTTP build cache backend like hazelcast-cache-node), monitor its port directly:

# Verify the build cache server is accepting connections
nc -zv build-cache.example.com 5071

1. Add Monitor → TCP.
2. Host: build-cache.example.com.
3. Port: 5071 (default Gradle build cache node port; check your settings.gradle for the actual port).
4. Check interval: 2 minutes.
5. Response timeout: 10 seconds.
6. Label: Gradle remote build cache.
7. Click Save.

Your settings.gradle build cache configuration typically looks like:

// settings.gradle.kts
buildCache {
    remote(HttpBuildCache::class) {
        url = uri("https://build-cache.example.com/cache/")
        isPush = true
    }
}

When the TCP monitor fires but your artifact repository is healthy, the build cache is down but dependency resolution will still work — builds will be slow but won't fail outright. This distinction helps your team triage correctly.

Step 5: Monitor the Maven Central Proxy (If Applicable)

Most Gradle projects proxy Maven Central through an internal repository to avoid external network dependencies in CI. If you don't run a proxy, your builds depend directly on Maven Central availability.

Monitor your proxy:

# Test that your Nexus/Artifactory proxy can resolve a known artifact
curl -I "https://nexus.example.com/repository/maven-central/org/springframework/boot/spring-boot/3.0.0/spring-boot-3.0.0.pom"

1. Add Monitor → HTTP.
2. URL: https://nexus.example.com/repository/maven-central/ (your proxy URL).
3. Check interval: 5 minutes.
4. Expected status: 200.
5. Label: Maven Central proxy.
6. Click Save.

Step 6: Monitor SSL Certificates for Gradle Infrastructure

Gradle verifies TLS certificates when downloading dependencies. An expired certificate on your artifact repository causes every ./gradlew build to fail with PKIX path building failed — one of the most confusing and hard-to-diagnose Gradle errors:

openssl s_client -connect nexus.example.com:443 2>/dev/null | openssl x509 -noout -dates
openssl s_client -connect ge.example.com:443 2>/dev/null | openssl x509 -noout -dates

For each domain in your Gradle infrastructure:

1. Add Monitor → SSL Certificate.
2. Domain: nexus.example.com (repeat for ge.example.com, build-cache.example.com).
3. Alert when expiry is within: 30 days.
4. Alert again: 14 days, 7 days, 3 days.
5. Click Save.

Gradle trust store: Gradle uses the JVM's trust store. If your certificates are issued by an internal CA, Gradle may still fail even after public CA renewal. Monitor both the certificate expiry and ensure the trust chain is complete.

Step 7: Configure Alerting

In Vigilmon under Settings → Notifications, set up your alert routing:

| Monitor | Trigger | Action | |---|---|---| | Artifact repository | Non-200 or keyword missing | Check systemctl status nexus; inspect disk space on artifact volume | | Gradle Enterprise | Non-200 | CI builds will silently slow down; check Develocity server logs | | Build cache TCP | Connection refused | Build cache node down; Gradle falls back to local cache — builds slow but functional | | Maven Central proxy | Non-200 | New dependency resolution blocked; check proxy connectivity to Maven Central | | SSL certificate | < 30 days to expiry | Renew certificate; alert all Gradle-using teams of the pending expiry |

Alert after: 2 consecutive failures for HTTP monitors; 1 failure for TCP monitors.

Common Gradle Infrastructure Failure Modes and What Vigilmon Catches

| Scenario | Vigilmon monitor | |---|---| | Nexus/Artifactory crashes | Artifact repository HTTP monitor fires; all new dependency resolution fails | | Build cache node OOM | TCP monitor on port 5071 fires; build times increase 2–5× silently | | SSL certificate expires on Nexus | SSL monitor alerts at 30 days; Gradle PKIX errors appear in CI | | Maven Central proxy loses upstream | Maven Central proxy monitor fires; new artifact resolution blocked | | Develocity server disk full | Health endpoint returns 500; build scans fail silently | | Network partition blocks artifact repo | All Gradle infrastructure monitors fire simultaneously | | Gradle Enterprise auth service fails | Develocity API returns 503; build scans and predictive test selection stop | | Build cache node disk full | Cache writes start failing; TCP port may still respond (monitor HTTP if available) |

When Gradle's supporting infrastructure fails silently, the symptoms are insidious: build times creep up, occasional Could not resolve errors appear, and developers blame flaky tests before realizing the build cache has been down for six hours. Vigilmon surfaces infrastructure failures at the moment they happen — artifact repository outages, build cache degradation, SSL certificate expiry — so your team can respond in seconds rather than spending hours debugging cryptic Gradle error messages.

Start monitoring your Gradle build infrastructure in under 5 minutes — register free at vigilmon.online.