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syslog-ng 3.37 released

by | Jun 7, 2022 | plan, technology | 0 comments

syslog-ng 3.37 has just been released, packages available in various platforms this week. You can get the detailed release notes on the github releases page, however I felt this would be a good opportunity to revisit my draft on the syslog-ng long term objectives and how this release builds in that direction.

The Edge: deployment and CI/CD

Being better at the edge means that we need to improve support for use-cases where syslog-ng is directly deployed on the node/server or is deployed close to such nodes or servers. One way to deploy syslog-ng is to use a .deb or .rpm package, but more and more syslog-ng is used in a container. Our production docker image is built based on Debian. Creating this image has been a partially manual process with all the issues that this entails.

With the merge of PR #4014 and #4003, Attila Szakács automated the entire workflow in a beautiful set of GitHub Action scripts, so that:

  • Official source and binary packages (for CentOS, Debian, Fedora and Ubuntu) are built automatically, once a syslog-ng release is tagged
  • The production docker image is built and pushed automatically, once the required binary packages are successfully built.

While we have pretty good, automated unit and functional tests, we did not test the installation packages themselves. Until now. András Mitzky implemented a smoke tests for the packages themselves, doing an install & upgrade and a start-stop test.

The Edge: Kubernetes

Increasingly, the edge is often running on an orchestrated, container based infrastructure, such as Kubernetes. Using syslog-ng in these systems were possible but required manual integration. With the merger of PR #4015, this is becoming more out of the box, expect another blog post on this in the coming days.

Application awareness

syslog is used as an infrastructure for logging serving a wide variety of applications. For these applications, logging is not a primary concern, unfortunately. The consequence is that they often produce invalid or incorrect data. To handle these applications well, we need to cater for these issues.

For instance, certain Aruba products use a timestamp like this:

2022-03-10 08:04:08,449

Looking at this, the problem might not even be apparent: it uses a comma to separate seconds from the fractions part.

You might argue that this is not an important problem at all, who needs fractions anyway?

There are two issues with this:

  1. Fractions might be important to some (e.g. for ordering with thousands of logs per second).
  2. It breaks the parsing the message itself (as the timestamp is embedded in a larger message), causing message related metadata to be incorrectly extracted (e.g. which device you want to attribute this message). This means that your dashboard in a SIEM may miss vital information.

And this is not the only similar case. See for this pull request for example for a similar example.

This is exactly why application awareness is important, fixing these cases means that your log data becomes more usable as a whole.

Usually it is not the programming of the solution that is difficult here, rather the difficulty lies in having to learn that the problem exists in the first place. If you have a similar parsing problem, please let us know by opening a GitHub issue. The past few such problems were submitted to us by the Splunk Connect for Syslog team, thanks for their efforts. Btw, sc4s is great if you want to feed syslog to Splunk and it uses syslog-ng internally.

On a similar note, we have improved the cisco-parser() that extracts fields from Cisco gear and added a parser for MariaDB audit logs. Both of these parsers are part of our app-parser() framework.


There are a few other features I find interesting, just a short summary

  • Type support is nearing completion. We added support for types in template expressions, groupset() & map-value-pairs().
  • We improved syslog-ng’s own trace messages: we added the unique message ID (e.g. $RCPTID) as a tag in all message related trace messages, so that you can correlate trace messages to a specific message. We also included type information as a part of the type support effort.
  • We improved handling of list/array like data in this pull request.
  • We extended our set of TLS options by adding support for sigalgs & client-sigalgs.


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