Tomdee

Deploying InfluxDB using Docker

There are a number of datastores aimed at the system monitoring space. These typically focus on storing time-series data. Currently, key players include

• Graphite
• InfluxDB
• OpenTSDB
• Prometheus

These different systems have different scopes; some focus entirely on the storage of data whilst others have additional features for graphing and alerting. Prometheus have a good overview.

I was looking for something that had a simple API for getting data in and simple installation and operational requirements were a must. I wasn't too keen on something that included too many bells and whistles, rather I preferred using the best tool for the job. If this meant using a different system for graphing or displaying the data then that was fine. Likewise for alerting.

Despite the wide support for Graphite, I settled on InfluxDB. It ticked the normal boxes of being modern, well supported and active. But crucially, I could dump data into it using curl, and there was a good Docker image for deploying it. The Tutum image lacks clustering and SSL support in the latest image but neither of these features are required.

Running InfluxDB

Creating a container running InfluxDB is as simple as

docker run -d --volume=/var/influxdb:/data --restart=always -e PRE_CREATE_DB="tomdee" -p 127.0.0.1:8083:8083 -p 127.0.0.1:8086:8086 --name influxdb  tutum/influxdb

This stores the data in a volume (/var/influxdb), ensures the container is restarted if it crashes or the server reboots, exposes the management APIs to the localhost and creates an initial database.

Managing InfluxDB

The influx CLI is available with  docker exec -ti influxdb /opt/influxdb/influx

The REST and Managment UIs are available over HTTP on ports 8083 and 8086. To connect to them remotely, an SSH tunnel can be used

ssh -L 8086:localhost:8086 user@example.com

Upgrading InfluxDB

The original container can be stopped and removed (since the data is in a volume).

docker rm -f influxdb

Then a new container can be pulled and started (without the need to create the database since it already exists)

docker pull tutum/influxdb

docker run -d --volume=/var/influxdb:/data --restart=always --name influxdb  tutum/influxdb

Backing up InfluxDB

Although influxdb has a hot backup feature I found it produced zero length files. Not good. Instead, I'm happy just taking a copy of the data on disk. If I was worried about data consistency I could pause the docker container whilst doing this.

e.g.  tar -czvf influxdb.$(date +%Y-%m-%d-%H.%M.%S).tgz /var/influxdb

Running InfluxDB on a single server for simple monitoring applications is easy and the operational requirements are low. Bugs in the backup code are a concern but at my scale I'm happy taking the risk.