spring-boot

Spring Boot + Alloy on another server

Ready-to-copy example: stacks/monitoring/agent/examples/spring-boot/.

On devops.local (once)

make setup          # LOKI_PUSH_USERNAME / LOKI_PUSH_PASSWORD
make monitoring
make middleware     # https://devops.local/loki/

On the application server

# 1) copy example (or your app repo + agent config)
scp -r stacks/monitoring/agent/examples/spring-boot user@appserver:/opt/note-keeper
scp stacks/monitoring/agent/config.docker.alloy user@appserver:/opt/note-keeper/../../config.docker.alloy
# simpler: copy whole agent/ tree
scp -r stacks/monitoring/agent user@appserver:/opt/alloy-agent

# 2) trust portal CA
curl -fk https://devops.local/ca.crt -o /opt/alloy-agent/examples/spring-boot/ca.crt

# 3) env
cd /opt/alloy-agent/examples/spring-boot
cp .env.example .env
# edit LOKI_PUSH_PASSWORD, AGENT_HOST

# 4) run app + agent
docker compose up -d --build

Layout on the app host:

Service	Role
note-keeper	your JAR; logs → stdout
alloy-agent	reads Docker logs via /var/run/docker.sock → https://devops.local/loki/api/v1/push

Do not add a Loki agent inside the app Dockerfile. Alloy runs as a sidecar/host agent.

Dockerfile changes (minimal)

Keep your multi-stage build. Ensure the JVM writes to the console (Spring default). Optional:

ENV JAVA_TOOL_OPTIONS="-Dlogging.pattern.console=%d{ISO8601} %-5level [%thread] %logger{36} - %msg%n"

Avoid logging only to files under /var/log unless you also mount them into Alloy.

Verify

Grafana → Explore → Loki:

{container="note-keeper"}
# or
{service="note-keeper"}
{host="note-keeper-prod"}

Actuator metrics (optional)

If you expose Micrometer Prometheus:

# application.yaml
management:
  endpoints:
    web:
      exposure:
        include: health,prometheus
  metrics:
    tags:
      application: note-keeper

Compose labels (already in the example):

labels:
  prometheus.io/scrape: "true"
  prometheus.io/port: "8080"
  prometheus.io/path: "/actuator/prometheus"

(Scraping from central Prometheus still needs network reachability or Alloy remote_write — logs work without that.)