2. Installation

The preferred way to install Pegasus is with native (RPM/DEB) packages. It is recommended that you also install HTCondor (formerly Condor) (yum, debian) from native packages.

2.1. Prerequisites

Pegasus has a few dependencies:

  • Java 1.8 or higher. Check with:

    # java -version
    java version "1.8.0"
  • Python 3.5 or higher. Check with:

    # python3 --version
    Python 3.6.9

    Python3 package yaml is also required, but it will be installed automatically if you use the RPM/DEB packages.

  • HTCondor (formerly Condor) 9.0 or higher. See http://www.cs.wisc.edu/htcondor/ for more information. You should be able to run condor_q and condor_status.

2.2. Optional Software

  • mysqlclient. Python module for MySQL access. Only needed if you want to store the runtime database in MySQL (default is SQLite). On server side, MySQL server 5.7 or higher is required, as Pegasus creates databases encoded in utf8mb4 charset.

  • psycopg2. Python module for PostgreSQL access. Only needed if you want to store the runtime database in PostgreSQL (default is SQLite)

2.3. Environment

To use Pegasus, you need to have the pegasus-* tools in your PATH. If you have installed Pegasus from RPM/DEB packages. the tools will be in the default PATH, in /usr/bin. If you have installed Pegasus from binary tarballs or source, add the bin/ directory to your PATH.

Example for bourne shells:

$ export PATH=/some/install/pegasus-5.0.X/bin:$PATH

If you want to use the API to generate workflows (Workflow API), you might also need to set your PYTHONPATH, PERL5LIB, or CLASSPATH. The right setting can be found by using pegasus-config:

$ export PYTHONPATH=`pegasus-config --python`
$ export PERL5LIB=`pegasus-config --perl`
$ export CLASSPATH=`pegasus-config --classpath`

2.4. RHEL / CentOS / Rocky / Alma / SL

Binary packages provided for: RHEL 7 x86_64 and RHEL 8 x86_64 (including OSes derived from RHEL: CentOS, Rocky, AlmaLinux, SL)

curl --output /etc/yum.repos.d/pegasus.repo \
dnf install epel-release
dnf install --enablerepo devel pegasus

2.5. Ubuntu

curl https://download.pegasus.isi.edu/pegasus/gpg.txt | apt-key add -
echo 'deb https://download.pegasus.isi.edu/pegasus/ubuntu jammy main' >/etc/apt/sources.list.d/pegasus.list
apt-get update
apt-get install pegasus

2.6. Debian

wget -O - https://download.pegasus.isi.edu/pegasus/gpg.txt | apt-key add -
echo 'deb https://download.pegasus.isi.edu/pegasus/debian bullseye main' >/etc/apt/sources.list.d/pegasus.list
apt-get update
apt-get install pegasus

2.7. Mac OS X

The easiest way to install Pegasus on Mac OS is to use Homebrew. You will need to install XCode and the XCode command-line tools, as well as Homebrew. Then you just need to tap the Pegasus tools repository and install Pegasus and HTCondor like this:

$ brew tap pegasus-isi/tools
$ brew install pegasus htcondor

Once the installation is complete, you need to start the HTCondor service. The easiest way to do that is to use the Homebrew services tap:

$ brew tap homebrew/services
$ brew services list
$ brew services start htcondor

You can also stop HTCondor like this:

$ brew services stop htcondor

And you can uninstall Pegasus and HTCondor using brew rm like this:

$ brew rm pegasus htcondor


It is also possible to install the latest development versions of Pegasus using the --HEAD arguments to brew install, like this: $ brew install --HEAD pegasus

2.8. Pegasus from Tarballs

The Pegasus prebuild tarballs can be downloaded from the Pegasus Download Page.

Use these tarballs if you already have HTCondor installed or prefer to keep the HTCondor installation separate from the Pegasus installation.

  • Untar the tarball

    $ tar zxf pegasus-*.tar.gz
  • include the Pegasus bin directory in your PATH

    $ export PATH=/path/to/pegasus-install/bin:$PATH
  • If you do not already have the Python3 package yaml, and GitPython, you can create a virtual environment. For example:

    $ python3 -m venv ~/pegasus-env
    $ . ~/pegasus-env/bin/activate
    $ python3 -m pip install pyyaml GitPython

2.9. Pegasus Python Packages for PyPi

  • To install the new Pegasus API.

    $ pip install pegasus-wms.api
  • To install old Python DAX API. The old DAX API is deprecated and will be removed in Pegasus 5.1.0.

    $ pip install pegasus-wms.dax

2.10. Mixing Environments (system/venv/conda/…)

If you need to mix a Pegasus install with other environments, such as using the Pegasus command line tools from a system install, but use the Python install and libraries from Conda, you can tell Pegasus to leave the environment alone. Note that by doing this, you will need to supply the requirements in your own environment. Set the environemnt variable:


Then install the following packages:


You should now be able to use the Pegasus command line tools.