Getting to know Telegraf

I first mentioned Telegraf in the My Monitoring Journey: Cacti, Graphite, Grafana & Chronograf post and then covered its installation and setup in the Installing & Setting up InfluxDB, Telegraf & Grafana post. Let’s now delve a little deeper, shall we?

The good news is that there’s a lot less to Telegraf’s configuration than what there is to InfluxDB so you’ll likely find this post easier to follow than the Getting to know InfluxDB and article.

What is it?

Before diving into configurations, it would be best to first cover off what Telegraf actually is. To quote the Telegraf GitHub page:

Telegraf is an agent written in Go for collecting, processing, aggregating, and writing metrics.

Design goals are to have a minimal memory footprint with a plugin system so that developers in the community can easily add support for collecting metrics from well known services (like Hadoop, Postgres, or Redis) and third party APIs (like Mailchimp, AWS CloudWatch, or Google Analytics).

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Navigating InfluxDB CLI

I’ve demonstrated a few InfluxDB commands in my Getting to know InfluxDB and InfluxDB: Retention Policies & Shard Groups posts but though it would be a good idea to write a post completely dedicated to useful CLI commands – so here it is.

SHOW DATABASES

This command is self explanatory. It lists all of your InfluxDB databases:

USE <DATBASE_NAME>

Enters a database so that subsequent commands will be run against it:

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InfluxDB: Retention Policies & Shard Groups

Note: This is a continuation of the Getting to know InfluxDB post. If you haven’t read it yet, I suggest you do before reading this post.

I found InfluxDB’s documentation around Retention Policies (RP) and Shard Groups quite unclear in parts and am therefore writing this post to assist others who find themselves feeling the same way.

What is a Retention Policy?

As the documentation says:

The part of InfluxDB’s data structure that describes for how long InfluxDB keeps data (duration), how many copies of those data are stored in the cluster (replication factor), and the time range covered by shard groups (shard group duration). RPs are unique per database and along with the measurement and tag set define a series.

When you create a database, InfluxDB automatically creates a retention policy called autogen with an infinite duration, a replication factor set to one, and a shard group duration set to seven days. See Database Management for retention policy management.

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Getting to know InfluxDB

I touched on InfluxDB in the My Monitoring Journey: Cacti, Graphite, Grafana & Chronograf post and then covered its installation and setup in the Installing & Setting up InfluxDB, Telegraf & Grafana post. Now it’s time to look at how the database actually works and commands we can use to integrate it.

InfluxDB Structure

In the latter mentioned post above we saw that Telegraf had created a telegraf  database in InfluxDB. Let’s now jump into InfluxDB and take a look at this database:

To view a list of all of the databases, issue the following show databases  command:

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