Prometheus monitoring example with Node.js
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README.md

Example Prometheus Monitoring

Goal

Setup monitoring with Prometheus and Grafana.

Steps

  1. Run sample server: npm install and node server
  2. Run Prometheus: see below
  3. Visit your running Prometheus and run queries
  4. Run Grafana: see below
  5. Add Prometheus data source (Url: http://localhost:9090, Access: direct)
  6. Import grafana-dashboard.json dashboard
  7. Create your own dashboard from the Prometheus queries

Requirements

  • Docker

Run

Modify: /prometheus-data/prometheus.yml, replace 192.168.0.10 with your own host machine's IP.
Host machine IP address: ifconfig | grep 'inet 192'| awk '{ print $2}'

docker run -p 9090:9090 -v "$(pwd)/prometheus-data":/prometheus-data prom/prometheus -config.file=/prometheus-data/prometheus.yml

Open Prometheus: http://localhost:9090

Example Queries

Throughput

Error rate

Range[0,1]: number of 5xx requests / total number of requests

sum(increase(http_request_duration_ms_count{code=~"^5..$"}[1m])) /  sum(increase(http_request_duration_ms_count[1m]))
Request Per Minute
sum(rate(http_request_duration_ms_count[1m])) by (service, route, method, code)  * 60

Response Time

Apdex

Apdex score approximation:
100ms target and 300ms tolerated response time

(
  sum(rate(http_request_duration_ms_bucket{le="100"}[1m])) by (service)
+
  sum(rate(http_request_duration_ms_bucket{le="300"}[1m])) by (service)
) / 2 / sum(rate(http_request_duration_ms_count[1m])) by (service)

Note that we divide the sum of both buckets. The reason is that the histogram buckets are cumulative. The le="100" bucket is also contained in the le="300" bucket; dividing it by 2 corrects for that. - Prometheus docs

95th Response Time
histogram_quantile(0.95, sum(rate(http_request_duration_ms_bucket[1m])) by (le, service, route, method))
Median Response Time:
histogram_quantile(0.5, sum(rate(http_request_duration_ms_bucket[1m])) by (le, service, route, method))
Average Response Time
avg(rate(http_request_duration_ms_sum[1m]) / rate(http_request_duration_ms_count[1m])) by (service, route, method, code)

Memory Usage

Average Memory Usage

In Megabyte.

avg(nodejs_external_memory_bytes / 1024 / 1024) by (service)

Reload config

Necessary when you modified prometheus-data.

curl -X POST http://localhost:9090/-/reload

Prometheus Data

avg(rate(http_request_duration_ms_sum[1m]) / rate(http_request_duration_ms_count[1m])) by (service, route, method, code)

Prometheus - Data

Prometheus Alerts

States of active alerts: pending, firing

Prometheus - Alert Pending Prometheus - Alert Firing

Grafana

Run

docker run -i -p 3000:3000 grafana/grafana

Open Grafana: http://localhost:3000

Username: admin
Password: admin

Setting datasource

Create a Grafana datasource with this settings:

Or use this curl request:

curl 'http://admin:admin@localhost:3000/api/datasources' -H 'Content-Type: application/json;charset=UTF-8' -H 'Accept: application/json, text/plain, */*' --data-binary '{"name":"DS_PROMETHEUS","type":"prometheus","url":"http://localhost:9090","access":"direct","jsonData":{"keepCookies":[]},"secureJsonFields":{}}' --compressed

Setting dashboard

Grafana Dashboard to import: /grafana-dashboard.json

Or use this curl request:

curl 'http://admin:admin@localhost:3000/api/dashboards/import' -H 'Accept-Encoding: gzip, deflate' -H 'Content-Type: application/json;charset=UTF-8' -H 'Accept: application/json, text/plain, */*' --data-binary '%{copy and paste grafana-dashboard.json}' --compressed

Grafana Dashboard

Grafana - Response Time Grafana - Throughput

Acknowledgements

This example is sponsored by Trace by RisingStack.