Prometheus

Prometheus is a popular open-source monitoring and alerting system. In 2016, Prometheus joined the Cloud Native Computing Foundation (CNCF), becoming the second hosted project after Kubernetes. The project has a very active developer and user community.

Prometheus provides remote_write and remote_read interfaces to utilize other database products as its storage engine. To enable users in the Prometheus ecosystem to leverage TDengine's efficient writing and querying capabilities, TDengine also supports these two interfaces.

With proper configuration, Prometheus data can be stored in TDengine via the remote_write interface and queried via the remote_read interface, fully utilizing TDengine's efficient storage and querying performance for time-series data and cluster processing capabilities.

Prerequisites

The following preparations are needed to write Prometheus data into TDengine:

• TDengine cluster is deployed and running normally
• taosAdapter is installed and running normally. For details, please refer to taosAdapter user manual
• Prometheus is installed. For installation of Prometheus, please refer to the official documentation

Configuration Steps

Configuring Prometheus is done by editing the Prometheus configuration file prometheus.yml (default location /etc/prometheus/prometheus.yml).

Configure Third-Party Database Address

Set the remote_read url and remote_write url to point to the domain name or IP address of the server running the taosAdapter service, the REST service port (taosAdapter defaults to 6041), and the name of the database you want to write to in TDengine, ensuring the URLs are formatted as follows:

• remote_read url: http://<taosAdapter's host>:<REST service port>/prometheus/v1/remote_read/<database name>
• remote_write url: http://<taosAdapter's host>:<REST service port>/prometheus/v1/remote_write/<database name>

Configure Basic Authentication

• username: <TDengine's username>
• password: <TDengine's password>

Example configuration of remote_write and remote_read in the prometheus.yml file

remote_write:
  - url: "http://localhost:6041/prometheus/v1/remote_write/prometheus_data"
    basic_auth:
      username: root
      password: taosdata

remote_read:
  - url: "http://localhost:6041/prometheus/v1/remote_read/prometheus_data"
    basic_auth:
      username: root
      password: taosdata
    remote_timeout: 10s
    read_recent: true

Verification Method

After restarting Prometheus, you can refer to the following example to verify that data is written from Prometheus to TDengine and can be correctly read.

Querying Written Data Using TDengine CLI

taos> show databases;
              name              |
=================================
 information_schema             |
 performance_schema             |
 prometheus_data                |
Query OK, 3 row(s) in set (0.000585s)

taos> use prometheus_data;
Database changed.

taos> show stables;
              name              |
=================================
 metrics                        |
Query OK, 1 row(s) in set (0.000487s)

taos> select * from metrics limit 10;
              ts               |           value           |             labels             |
=============================================================================================
 2022-04-20 07:21:09.193000000 |               0.000024996 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:14.193000000 |               0.000024996 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:19.193000000 |               0.000024996 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:24.193000000 |               0.000024996 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:29.193000000 |               0.000024996 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:09.193000000 |               0.000054249 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:14.193000000 |               0.000054249 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:19.193000000 |               0.000054249 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:24.193000000 |               0.000054249 | {"__name__":"go_gc_duration... |
 2022-04-20 07:21:29.193000000 |               0.000054249 | {"__name__":"go_gc_duration... |
Query OK, 10 row(s) in set (0.011146s)

Using promql-cli to Read Data from TDengine via remote_read

Install promql-cli

go install github.com/nalbury/promql-cli@latest

Query Prometheus data while TDengine and taosAdapter services are running

ubuntu@shuduo-1804 ~ $ promql-cli --host "http://127.0.0.1:9090" "sum(up) by (job)"
JOB           VALUE    TIMESTAMP
prometheus    1        2022-04-20T08:05:26Z
node          1        2022-04-20T08:05:26Z

Query Prometheus data after pausing the taosAdapter service

ubuntu@shuduo-1804 ~ $ sudo systemctl stop taosadapter.service
ubuntu@shuduo-1804 ~ $ promql-cli --host "http://127.0.0.1:9090" "sum(up) by (job)"
VALUE    TIMESTAMP

note

• The default subtable names generated by TDengine are unique IDs based on a set of rules.