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CentOS (Linux)

Update to CentOS 7

As of July 2016, CentOS 7 has become the standard PACS-supported linux distribution.  This leads to the following changes for PACS-supported linux machines:
  • All new servers and workstations will be installed with CentOS 7
  • Work has begun to update existing workstations to CentOS 7, with a tenative completion date of Jan 2017
  • Servers will be updated to CentOS 7 as time/circumstance permits, with a tenative completion date of May 2017.  (Any exceptions will be evaluated on a case-by-case, and may result in the server being declared "moribund" and removed from physics-astronomy NFS/domain trust.)

 Why CentOS? A FAQ

Up to this point, Scientific Linux has been the PACS-supported linux distribution.  Why the change to CentOS?  

Q:  What's the difference between CentOS and Scientific Linux?
A:  Both are derivatives of Red Hat and are binary compatible with Red Hat.  CentOS differs from Scientific Linux in the areas of packaging and distribution rather than content.  The changes of moving from a RHEL-6 to RHEL-7 base will be more significant than moving from Scientific Linux to CentOS.

Q:  Why are we moving from Scientific Linux to CentOS?
A:  There are several reasons why:
  1.  In 2014, Red Hat and CentOS entered into collaboration, effectively making CentOS the "official" community distro of RHEL.  (cf.
  2. The campus licence for RHEL (which we used prior to our move to Scientific Linux) is expiring at the end of June and is not being renewed.  UW-IT has moved to CentOS as their distro of choice.  (cf.
  3. Our Atlas group uses CERN-based code, and CERN is moving from Scientific Linux to CentOS with version 7.  (cf.
  4. The LSST group has explicitly asked for CentOS for one of their latest servers, based on what the LSST collaboration as a whole is using.

Changes/Issues w/ CentOS 7

There are a number of user-noticable changes and/or issues with the move to CentOS 7 (mostly due to the v6 to v7 update, rather than the change to CentOS).  What follows is a list of some of the more notable ones with reasons and work-arounds where available.

  • Gnome desktop updated to v3
    The gnome desktop has been updated to v3, and, for better or worse, has a new look and feel.  There is a "classic" mode available, which may be selected by clicking on the 'gear' icon before entering your password.  This 'gear' icon is also where you would choose the KDE or MATE desktop if that is your preference.
  • MATE desktop now available
    The MATE (Mah-TAY, as in yerba mate) is now available as an alternative to the new Gnome-3 desktop.  I may be selected by clicking on the 'gear' icon before entering your password.
  • Desktop selection stored locally per machine
    Under v6, your desktop selection (Gnome, KDE, etc) was stored in your home directory, and once you selected your desktop choice on one machine, that choice was used for all machines.  With v7, this is no longer the case, as your desktop choice is stored locally on the workstation itself.  Hence, the first time you log into any new (or reinstalled) machine, you will have to set your desktop preference.
  • Mathematica is now mathematica10
    With this update we have upgraded Mathematica to v10.4.  To invoke it, issue the command 'mathematica10' from a terminal window/command line.
  • Acroread is gone
    Acroread, the Adobe pdf reader is no longer available.  Adobe stopped supporting the linux version of acroread back in 2013, and we have been running that final version ever since.  With the update to v7, this old executable no longer runs.  Alternatives are to open your pdf files with 'evince' (the default Gnome pdf reader), or with 'firefox' (which will use its pdf plugin).
  • IDL is now in /astro/apps6
    IDL is no longer being installed locally on the workstations.  It is now available from /astro/apps6.  To use it, remove all old IDL configuration lines from your .cshrc file and add /astro/apps6/opt/idl83/idl/bin to your path.
  • Google-Chrome is now available
    Google chrome is now available as 'chrome' or 'google-chrome' on CentOS 7 workstations.
  • LaTeX style & other files have moved
    The latex style & other files have moved, and can now be found beneath /usr/share/texlive/texmf-dist/.  If you have set your TEXINPUTS or other TeX environmentals in your .cshrc/.bashrc/.profile file, you will need to adjust these.
  • AstroConda has been installed
    The AstroConda suite has been installed in /astro/apps7/opt/AstroConda. Bash shell users can 'source /astro/apps7/opt/AstroConda.setup/' in their .bashrc file to enable it.  (AstroConda is bash-based, so I have no idea if it can usefully be used by [t]csh users -- they supply no info for that.)
  • IRAF now comes from the AstroConda suite 
    The various old installations of IRAF do not work with our CentOS 7 workstations.  IRAF is available however through the newly installed AstroConda suite (qv). Those running the bash shell can 'source /astro/apps7/opt/AstroConda.setup/' in their .bashrc file to get the full IRAF variant of AstroConda.  [T]csh users can use the IRAF components (not sure about the rest, AstroConda is bash-centric) by executing 'source /astro/apps7/opt/AstroConda.setup/iraf.csh' in their .cshrc file.

 Further Info

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