Prometheus

Expose metrics related to IAM and proxied upstream services in Prometheus exposition format, which can be scraped by a Prometheus Server.

Terminology

• plugin: a plugin executing actions inside IAM before or after a request has been proxied to the upstream API.
• Service: the IAM entity representing an external upstream API or microservice.
• upstream service: this refers to your own API/service sitting behind IAM, to which client requests are forwarded.

Configuration

This plugin is compatible with requests with the following protocols:

• http
• https
• tcp
• tls
• grpc
• grpcs

This plugin is compatible with DB-less mode.

Enabling the plugin on a Service

With a database

Configure this plugin on a Service by making the following request:

$ curl -X POST http://localhost:8001/services/{service}/plugins \
    --data "name=prometheus"

Without a database

Configure this plugin on a Service by adding this section do your declarative configuration file:

plugins:
- name: prometheus
  service: {service}
  config:

In both cases, {service} is the id or name of the Service that this plugin configuration will target.

Global plugins

• Using a database, all plugins can be configured using the http://localhost:8001/plugins/ endpoint.
• Without a database, all plugins can be configured via the plugins: entry on the declarative configuration file.

A plugin which is not associated to any Service, Route or Consumer (or API, if you are using an older version of IAM) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Metrics are available on the Admin API at the http://localhost:8001/metrics endpoint. Note that the URL to the Admin API will be specific to your installation; see Accessing the metrics below.

This plugin records and exposes metrics at the node-level. Your Prometheus server will need to discover all IAM nodes via a service discovery mechanism, and consume data from each node's configured /metric endpoint. IAM nodes that are set to proxy only (that is their Admin API has been disabled by specifying admin_listen = off) will need to use a custom Nginx configuration template to expose the metrics data.

Grafana dashboard

Metrics exported by the plugin can be graphed in Grafana using a drop in dashboard: https://grafana.com/dashboards/7424.

Available metrics

• Status codes: HTTP status codes returned by upstream services. These are available per service and across all services.
• Latencies Histograms: Latency as measured at IAM:
  • Request: Total time taken by IAM and upstream services to serve requests.
  • IAM: Time taken for IAM to route a request and run all configured plugins.
  • Upstream: Time taken by the upstream service to respond to requests.
• Bandwidth: Total Bandwidth (egress/ingress) flowing through IAM. This metric is available per service and as a sum across all services.
• DB reachability: A gauge type with a value of 0 or 1, representing if DB can be reached by an IAM node or not.
• Connections: Various Nginx connection metrics like active, reading, writing, and number of accepted connections.

Here is an example of output you could expect from the /metrics endpoint:

$ curl -i http://localhost:8001/metrics
HTTP/1.1 200 OK
Server: openresty/1.11.2.5
Date: Mon, 11 Jun 2018 01:39:38 GMT
Content-Type: text/plain; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Access-Control-Allow-Origin: *

# HELP kong_bandwidth_total Total bandwidth in bytes for all proxied requests in IAM
# TYPE kong_bandwidth_total counter
kong_bandwidth_total{type="egress"} 1277
kong_bandwidth_total{type="ingress"} 254
# HELP kong_bandwidth Total bandwidth in bytes consumed per service in IAM
# TYPE kong_bandwidth counter
kong_bandwidth{type="egress",service="google"} 1277
kong_bandwidth{type="ingress",service="google"} 254
# HELP kong_datastore_reachable Datastore reachable from IAM, 0 is unreachable
# TYPE kong_datastore_reachable gauge
kong_datastore_reachable 1
# HELP kong_http_status_total HTTP status codes aggreggated across all services in IAM
# TYPE kong_http_status_total counter
kong_http_status_total{code="301"} 2
# HELP kong_http_status HTTP status codes per service in IAM
# TYPE kong_http_status counter
kong_http_status{code="301",service="google"} 2
# HELP kong_latency Latency added by IAM, total request time and upstream latency for each service in IAM
# TYPE kong_latency histogram
kong_latency_bucket{type="kong",service="google",le="00001.0"} 1
kong_latency_bucket{type="kong",service="google",le="00002.0"} 1
.
.
.
kong_latency_bucket{type="kong",service="google",le="+Inf"} 2
kong_latency_bucket{type="request",service="google",le="00300.0"} 1
kong_latency_bucket{type="request",service="google",le="00400.0"} 1
.
.
kong_latency_bucket{type="request",service="google",le="+Inf"} 2
kong_latency_bucket{type="upstream",service="google",le="00300.0"} 2
kong_latency_bucket{type="upstream",service="google",le="00400.0"} 2
.
.
kong_latency_bucket{type="upstream",service="google",le="+Inf"} 2
kong_latency_count{type="kong",service="google"} 2
kong_latency_count{type="request",service="google"} 2
kong_latency_count{type="upstream",service="google"} 2
kong_latency_sum{type="kong",service="google"} 2145
kong_latency_sum{type="request",service="google"} 2672
kong_latency_sum{type="upstream",service="google"} 527
# HELP kong_latency_total Latency added by IAM, total request time and upstream latency aggreggated across all services in IAM
# TYPE kong_latency_total histogram
kong_latency_total_bucket{type="kong",le="00001.0"} 1
kong_latency_total_bucket{type="kong",le="00002.0"} 1
.
.
kong_latency_total_bucket{type="kong",le="+Inf"} 2
kong_latency_total_bucket{type="request",le="00300.0"} 1
kong_latency_total_bucket{type="request",le="00400.0"} 1
.
.
kong_latency_total_bucket{type="request",le="+Inf"} 2
kong_latency_total_bucket{type="upstream",le="00300.0"} 2
kong_latency_total_bucket{type="upstream",le="00400.0"} 2
.
.
.
kong_latency_total_bucket{type="upstream",le="+Inf"} 2
kong_latency_total_count{type="kong"} 2
kong_latency_total_count{type="request"} 2
kong_latency_total_count{type="upstream"} 2
kong_latency_total_sum{type="kong"} 2145
kong_latency_total_sum{type="request"} 2672
kong_latency_total_sum{type="upstream"} 527
# HELP kong_nginx_http_current_connections Number of HTTP connections
# TYPE kong_nginx_http_current_connections gauge
kong_nginx_http_current_connections{state="accepted"} 8
kong_nginx_http_current_connections{state="active"} 1
kong_nginx_http_current_connections{state="handled"} 8
kong_nginx_http_current_connections{state="reading"} 0
kong_nginx_http_current_connections{state="total"} 8
kong_nginx_http_current_connections{state="waiting"} 0
kong_nginx_http_current_connections{state="writing"} 1
# HELP kong_nginx_metric_errors_total Number of nginx-lua-prometheus errors
# TYPE kong_nginx_metric_errors_total counter
kong_nginx_metric_errors_total 0

Accessing the metrics

In most configurations, the IAM Admin API will be behind a firewall or would need to be set up to require authentication, here are a couple of options to allow access to the /metrics endpoint to Prometheus.

1. You can proxy the Admin API through IAM itself then use plugins to limit access. For example, you can create a route /metrics endpoint and have Prometheus access this endpoint to slurp in the metrics while preventing others from access it. The specifics of how this is configured will depend on your specific setup. Read the docs Securing the Admin API for details.

2. Finally, you could serve the content on a different port with a custom server block using a custom Nginx template with IAM.

   The following block is an example custom nginx template which can be used by IAM:

    server {
        server_name kong_prometheus_exporter;
        listen 0.0.0.0:9542; # can be any other port as well
   
        location / {
            default_type text/plain;
            content_by_lua_block {
                local serve = require "kong.plugins.prometheus.serve"
                serve.prometheus_server()
            }
        }
   
        location /nginx_status {
            internal;
            access_log off;
            stub_status;
        }
    }