Posts Tagged ‘Prometheus’

A Prometheus exporter for Dovecot

Monday, January 16th, 2017

To start this year’s series of contribution to the open source community, we’re proud to announce the release of yet another tool that we use to monitor our production setup, namely a Prometheus metrics exporter for the Dovecot POP/IMAP mail server.

One of the key features of Prometheus is that it is very well suited for white box monitoring, i.e. having graphs and alerts based on internal state of the program, as opposed to testing just the externally visible behaviour of the system. For Dovecot we’re very interested in using white box monitoring to be able to graph traffic and resource usage per customer, domain and user.

It turns out that we’re in luck, as Dovecot 2.1 and later ship with a statistics module that provides access to this kind information. When enabled, Dovecot binds to an additional UNIX or TCP socket on which metrics are exported. The Dovecot exporter that we’ve published on GitHub is basically a light-weight proxy that converts the metrics from Dovecot’s format into Prometheus metrics, exporting them over HTTP.

Below is a screenshot of our Dovecot exporter in action. The graph shows the rate of IMAP commands sent to our mail server, broken down by IMAP username.

If your email setup is also based on Dovecot and use Prometheus for monitoring, we’d like to invite you to give this exporter a try as well. Feel free to file issues or send pull requests on GitHub.

Birdwatcher: Accessing Calico/BIRD metrics through Prometheus

Friday, October 28th, 2016

At Kumina we maintain a Kubernetes setup running on Amazon EC2. For the low-level networking between containers, we make use of Calico. Calico configures all of our EC2 systems to form a mesh network. The systems in this mesh network all run an instance of the BIRD Internet Routing Daemon.

One of the problems we ran into with Calico is that it’s sometimes hard to get a holistic view of the state of the system. Calico ships with a utility called calicoctl that can be used to print the state of a single node in the mesh, but using this utility can easily become laborious as the number of EC2 instances increases.

Given that we already make strong use of Prometheus for our monitoring, we’ve solved this by writing a tool called Birdwatcher that exports the metrics generated by BIRD in Prometheus’ format. This allows us to put alerts in place for when an excessive number of changes to routes occur, or when routes simply fail to work for a prolonged period of time.

Today we’re happy to announce that Birdwatcher is now available on our company’s GitHub page. If you’re a user of both Calico and Prometheus, be sure to give it a try. Enjoy!