Telegraf

juju deploy telegraf

20.04 LTS 18.04 LTS 16.04 LTS

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Overview

This is a subordinate charm to deploy the telegraf metrics agent to collect metrics from related services. The metrics may be scraped by or pushed to supported systems such as Prometheus, Graphite or InfluxDB.

For details about telegraf see: https://github.com/influxdata/telegraf

Usage

Deploy telegraf alongside your service, and also a time series storage (in this case, influxdb)

juju deploy telegraf 
juju deploy influxdb 
juju deploy some-service

Add the relations:

juju add-relation telegraf:juju-info some-service:juju-info 
juju add-relation telegraf:influxdb-api influxdb:api

Network space support

The charm support the 'prometheus-client' binding for the prometheus-client interface. If the charm is deployed with 'prometheus-client' bound to a network space then the client relation will contain the network space IP address rather than the unit's private address.

Configuration

Installation method: deb or snap

The charm can deploy using either a deb (default) or a snap installation. juju config telegraf install_method=deb # to use the debian package juju config telegraf install_method=snap # to use the snap Only the needed package (deb or snap) will be installed.

To change the snap channel: juju config telegraf snap_channel=beta

Prometheus Output

By default, Prometheus output is presented available for scraping.

InfluxDB Output

When related to an InfluxDB service, metrics will be pushed to a database named telegraf.

Apache Input

For the apache input plugin, the charm provides the apache relation which uses apache-website interface. Current apache charm disables mod_status and in order to telegraf apache input to work status should be removed from the list of disable_modules in the apache charm config.

Postgresql & MySQL input

Due to relation scope issues, two relations need to be established between telegraf and the postgresql service. first a plain juju-info relation to get standard system metrics and a db-admin relation for PostgreSQL database metrics. eg.:

```
juju add-relation postgresql:juju-info telegraf
juju add-relation postgresql:db-admin telegraf
```

Similarly, for MySQL:

```
juju add-relation mysql:juju-info telegraf
juju add-relation mysql:db-admin telegraf
```

Rabbitmq Input

You will need both relations:

  • juju add-relation telegraf:juju-info rabbitmq-server:juju-info to start serving data
  • juju add-relation telegraf:amqp rabbitmq-server:amqp for the actual rabbitmq communication

This relation requires rabbitmq management plugin to be activated: juju set rabbitmq-server management_plugin=true

The rabbitmq charm doesn't appear to give true administrator privileges to relations. On the rabbitmq unit, you will need to grant permissions for the newly created charm user: rabbitmqctl set_permissions -p openstack telegraf-telegraf-XX ".*" ".*" ".*"

The charm configures telegraf to drop idle_since metrics (e.g. idle_since="2018-08-14 0:24:04") which break time series in Prometheus, since any difference in labels (presence or lack, and content) is treated as a new series.

Advanced

Input

A basic set of input plugins are setup by default, which can be overriden with the inputs_config configuration option. Both of these accept raw telegraf configuration.

To configure any of the (default or via relation) plugins, the extra_options charm config can be used. It's yaml, that needs to be encoded as a string in the config. For example:

```yaml
telegraf:
# The trailing | means the following indented section is all one string.
extra_options: |
    inputs:
        cpu:
            percpu: false
            fielddrop: ["time_*"]
        disk:
            mount_points: ["/"]
            ignore_fs: ["tmpfs", "devtmpfs"]
        elasticsearch:
            local: false
            cluster_health: true
        postgresql:
            databases: ["foo", "bar"]
            tagpass: 
                db: ["template", "postgres"]
    outputs:
        influxdb:
            precision: ms
```

This extra options will only be applied to plugins configured via relations and the following list (defined in templates/base_inputs.conf):

- inputs.cpu
- inputs.disk
- inputs.diskio
- inputs.mem
- inputs.net
- inputs.netstat
- inputs.swap
- inputs.system
Output

The only output plugin supported via relation is influxdb, any other output plugin needs to be configured manually (via juju set).

To use a different metrics storage such as Graphite, the raw telegraf plugin configuration needs to be set as a string in outputs_config configuration. For example:

```yaml
telegraf:
  # The trailing | indicates a multiline string in yaml.
  outputs_config: |
    [[outputs.graphite]]
    servers = ["10.0.3.231:2003"]
    prefix = "juju_local.devel.telegraf"
    timeout = 10
```

This will make telegraf agents to send the metrics to the graphite instance.

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