Telegraf

Telegraf collects metrics from a wide array of inputs and writes them to a wide array of outputs. It is plugin-driven for both collection and output of data so it is extendable. It is written in Go, which means that it is a compiled and standalone binary that can be run on any system with no need for external dependencies, or package management tools required.

Telegraf is an open source tool. It contains over 200 plugins for gathering and writing different types of data written by people who work with that data.

Before you begin

Ingest metrics using Telegraf plugin to TimescaleDB

Generating a configuration file

  1. Check the version of Telegraf that you installed:

    1. telegraf --version

  2. Generate a sample configuration file for Telegraf using:

    1. telegraf --input-filter=cpu --output-filter=postgresql config > telegraf.conf

    A configuration file enables a CPU input plugin that samples various metrics about CPU usage, and the PostgreSQL output plugin. The file also includes all available input, output, processor, and aggregator plugins. These are commented out commented out by default. You can enable them as required.

  3. Test the sample configuration file telegraf.conf that you generated:

    1. telegraf --config telegraf.conf --test

    An output similar to this appears:

    1. 2022-11-28T12:53:44Z I! Starting Telegraf 1.24.3
    3. 2022-11-28T12:53:44Z I! Available plugins: 208 inputs, 9 aggregators, 26 processors, 20 parsers, 57 outputs
    5. 2022-11-28T12:53:44Z I! Loaded inputs: cpu
    7. 2022-11-28T12:53:44Z I! Loaded aggregators:
    1. 2022-11-28T12:53:44Z I! Loaded processors:
    1. 2022-11-28T12:53:44Z W! Outputs are not used in testing mode!
    3. 2022-11-28T12:53:44Z I! Tags enabled: host=localhost
    5. > cpu,cpu=cpu0,host=localhost usage_guest=0,usage_guest_nice=0,usage_idle=90.00000000087311,usage_iowait=0,usage_irq=0,usage_nice=0,usage_softirq=0,usage_steal=0,usage_system=6.000000000040018,usage_user=3.999999999996362 1669640025000000000
    7. > cpu,cpu=cpu1,host=localhost usage_guest=0,usage_guest_nice=0,usage_idle=92.15686274495818,usage_iowait=0,usage_irq=0,usage_nice=0,usage_softirq=0,usage_steal=0,usage_system=5.882352941192206,usage_user=1.9607843136712912 1669640025000000000
    9. > cpu,cpu=cpu2,host=localhost usage_guest=0,usage_guest_nice=0,usage_idle=91.99999999982538,usage_iowait=0,usage_irq=0,usage_nice=0,usage_softirq=0,usage_steal=0,usage_system=3.999999999996362,usage_user=3.999999999996362 1669640025000000000

Configuring the PostgreSQL output plugin

  1. Open the telegraf.conf file using an editor of your choice:

    1. nano telegraf.conf

  2. Set the connection parameter in the [[outputs.postgresql]] section to the<SERVICE URL> of the TimescaleDB service that you created:

    1. connection = "<SERVICE URL>"

  3. Create a hypertable by adding the table_template parameter in the config file to execute when creating a new table:

    1. ## Templated statements to execute when creating a new table.
    3. # create_templates = [
    5. #   '''CREATE TABLE {{ .table }} ({{ .columns }})''',
    7. # ]
    8. `
    10. #  table_template=`CREATE TABLE IF NOT EXISTS {TABLE}({COLUMNS}); SELECT create_hypertable({TABLELITERAL},'time',chunk_time_interval := INTERVAL '1 week',if_not_exists := true);`
    11. `

Viewing the metrics collected by Telegraf in TimescaleDB

  1. Run Telegraf to collect the metrics:

    1. telegraf --config telegraf.conf

    The output uses loaded inputs cpuand outputs postgresql along with global tags, and the intervals with which the agent collects the data from the inputs, and flushes to the outputs.

    An output similar to this appears:

    1. 2022-12-05T12:32:00Z I! Starting Telegraf 1.24.3
    3. 2022-12-05T12:32:00Z I! Available plugins: 208 inputs, 9 aggregators, 26 processors, 20 parsers, 57 outputs
    5. 2022-12-05T12:32:00Z I! Loaded inputs: cpu
    7. 2022-12-05T12:32:00Z I! Loaded aggregators:
    1. 2022-12-05T12:32:00Z I! Loaded processors:
    1. 2022-12-05T12:32:00Z I! Loaded outputs: postgresql
    3. 2022-12-05T12:32:00Z I! Tags enabled: host=test
    5. 2022-12-05T12:32:00Z I! [agent] Config: Interval:10s, Quiet:false, Hostname:"test", Flush Interval:10s

  2. Stop running Telegraf to collect the metrics after approximately 15 to 20 seconds.

  3. Connect to TimescaleDB and provide the <PASSWORD> for tsdbadmin:

    1. psql <SERVICE URL>
    3. Password for user tsdbadmin: <PASSWORD>

  4. View the metrics collected in the cpu table in tsdb:

    1. SELECT*FROM cpu;

    An output similar to this appears:

    1. time         |    cpu    |               host               | usage_guest | usage_guest_nice |    usage_idle     | usage_iowait | usage_irq | usage_nice | usage_softirq | usage_steal |    usage_system     |     usage_user
    1. ---------------------+-----------+----------------------------------+-------------+------------------+-------------------+--------------+-----------+------------+---------------+-------------+---------------------+---------------------
    3. 2022-12-05 12:25:20 | cpu0      | hostname |           0 |                0 | 83.08605341237833 |            0 |         0 |          0 |             0 |           0 |   6.824925815961274 |  10.089020771444481
    5. 2022-12-05 12:25:20 | cpu1      | hostname |           0 |                0 | 84.27299703278959 |            0 |         0 |          0 |             0 |           0 |   5.934718100814769 |   9.792284866395647
    7. 2022-12-05 12:25:20 | cpu2      | hostname |           0 |                0 | 87.53709198848934 |            0 |         0 |          0 |             0 |           0 |   4.747774480755411 |   7.715133531241037
    9. 2022-12-05 12:25:20 | cpu3      | hostname|           0 |                0 | 86.68639053296472 |            0 |         0 |          0 |             0 |           0 |    4.43786982253345 |   8.875739645039992
    11. 2022-12-05 12:25:20 | cpu4      | hostname |           0 |                0 | 96.15384615371369 |            0 |         0 |          0 |             0 |           0 |  1.1834319526667423 |  2.6627218934917614

  5. To view the average usage per CPU core, use:

    1. SELECT cpu, avg(usage_user) FROM cpu GROUP BY cpu;

    An output similar to this appears:

    1. cpu    |         avg
    1.  -----------+---------------------
    3.   cpu7      | 0.36239363864003277
    5.   cpu-total |  2.7778985775548013
    7.   cpu4      |  1.9990184779524285
    9.   cpu2      |   4.083993994915682
    11.   cpu0      |   5.281711648540422
    13.   cpu1      |  4.9013756546309155
    15.   cpu6      |  0.6719913538159535
    17.   cpu5      |  1.0512637475474937
    19.   cpu3      |   3.871919066617788

For more information about the options that you can configure in Telegraf, see PostgreQL output plugin.

Visualizing data in Grafana

  1. Log in to Grafana and navigate to Configuration → Data sources. The data sources page lists previously configured data sources for the Grafana instance.
  2. Click Add data source to see a list of all supported data sources.
  3. Type PostgreSQL in the search field and click Select.
  4. Configure the data source:
    • In the Name field, type the name that you would like to use for the dataset.
    • In the PostgreSQL Connection section, type the Database, User, and Password fields using the .sql file that you downloaded when creating the TimescaleDB service.
    • In the Host field, type <HOST>:<PORT> from the .sql file that you downloaded.
    • Set TLS/SSL Mode to require.
    • In PostgreSQL details, enable TimescaleDB
  5. Click Save & test. If the connection is successful, Database Connection OK is shown.

When you have configured TimescaleDB as a data source in Grafana, you can create panels that are populated with data using SQL.