Athena Releases

Last update: 20 Sep 2017 [History] [Edit]

Release Numbers

When a particular build of an Athena project is deemed ready for production it will be installed as a numbered release onto the ATLAS production CVMFS server.

ATLAS software is numbered according to the following scheme:


A refers to the release series, e.g., release series 21 is being used for Run 2 simulation and data taking in 2017 and 2018.

B is the release flavour and usually corresponds to a particular branch in the git repository for which the code base needs to be different. e.g., 21.0 is the release for MC16 simulation (and Tier-0 reconstruction), but 21.3 is used as a development branch with MC18 code changes in it; 20.1 contains the extra-stable variant of the code for online data taking.

Principle release flavours are:

Flavour Purpose
0 Tier-0 reconstruction and corresponding simulation production
1 High Level Trigger online data taking
2 Derivations and Analysis
3 Simulation development
5 The union of .0 and .1, Tier-0 but with most recent trigger changes (also known as TrigMC)
9 Upgrade studies

Note that there is a strong correspondence between release flavour and Athena Project, However, it is not absolute, e.g., AthDerivation and AthAnalysisBase would both be built from flavour 2.

X is the major release number, monotonically increasing as code is developed with bugs fixed and enhancements added.

Y is used is a minor release number is required for developments that branched from an older major release. e.g., 21.0.20.Y contains any fixes required for MC16a, as releases 21.0.21 onwards contained incompatible changes for MC16c.

If needed additional sub-minor release numbers can be added, but this would be a rare occurrence.

Setting Up A Release

To setup a production release the release number and project need to be specified to asetup, e.g.,

asetup Athena,21.0.23

Finding Releases and Release Information

It is very easy to see which production releases are available, just by looking in CVMFS, e.g.,

$ ls /cvmfs/
21.1.0  21.1.1

Where the release series and flavour are encoded in the highest level directory, then the project, then the release number (/cvmfs/

See the full asetup users guide for further options.

Release Notes

When a git tag is made for a production release the release coordinator will add some release notes to the tag, which you can read directly in GitLab (just navigate to the tag of interest) or through the git command line:

$ git show release/21.0.23
tag release/21.0.23
Tagger: Hass AbouZeid <>
Date:   Fri May 12 10:17:36 2017 +0000

Release used to reconstruct LHC commisioning data, and cosmics 
(combined muon rec turned off) at the Tier0.  This release does 
*not* conserve FT0 policy with respect to 21.0.22
commit a55926e1404de0dc997ac370b53a0c3a3b1cff8d

Mapping Releases to Nightly Builds

If you need to find out which nightly build corresponded to a particular release the ReleaseData file contains useful information:

$ cat /cvmfs/ 
nightly name:21.0
project name:Athena
nightly release:a55926e140

You can also search for references with the right tag or hash in git using git describe:

$ git describe --tags --match 'release/*' nightly/21.0/2017-05-11T2125

$ git describe --tags --match 'nightly/*' release/21.0.23            

$ git describe --tags --match 'nightly/*' a55926e140