# 5.1. Installation

This file is a very short overview of building and installing the PMIx library. Much more information is available in the How-To section on the PMIx web site.

## 5.1.1. Developer Builds

If you have checked out a DEVELOPER’S COPY of PMIx (i.e., you checked out from Git), you should read the Developer’s Guide section before attempting to build PMIx. You must then run:

    shell$ ./autogen.pl

You will need very recent versions of GNU Autoconf, Automake, and Libtool. If `autogen.pl` fails, read the Developer’s Guide. If anything else fails, read the Developer’s Guide. Finally, we suggest reading the Developer’s Guide.

Note

Developer’s copies of OpenPMIx typically include a large performance penalty at run-time because of extra debugging overhead.

## 5.1.2. User Builds

Building PMIx is typically a combination of running `configure` and `make`. Execute the following commands to install the PMIx system from within the directory at the top of the tree:

    shell$ ./configure --prefix=/where/to/install
    [...lots of output...]
    shell$ make all install

Note

This version of PMIx requires the following 3rd-party packages to build and operate:

- either the Libevent package (any version of Libevent greater than or equal to 2.0.21 is acceptable) or the libev package (no minimum version has been identified).

- the HWLOC package for providing topology information to both the host environment (by collecting local inventory for rollup) and local client processes. Any version of HWLOC greater than 1.10 is supported, although versions in the 2.x series are recommended.

Note that you must point `configure` at these packages if they are in a non-standard location - libevent using the `--with-libevent=<dir>` option; libev using the `-with-libev=<dir>` option, and HWLOC package using the `--with-hwloc=<dir>` option. In all cases, PMIx will automatically detect these packages in standard locations and use them unless otherwise specified using the respective configure option.

If you need special access to install, then you can execute `make all` as a user with write permissions in the build tree, and a separate `make install` as a user with write permissions to the install tree.

Compiling support for specific compilers and environments may require additional command line flags when running `configure`. See the compiler flags entry for more details.

Note that VPATH builds are fully supported. For example:

    shell$ tar xf pmix-X.Y.Z.tar.gz
    shell$ cd pmix-X.Y.Z
    shell$ mkdir build
    shell$ cd build
    shell$ ../configure ...your options...
    [...lots of output...]
    shell$ make all install

Parallel builds are also supported (although some versions of `make`, such as GNU make, will only use the first target listed on the command line when executable parallel builds). For example (assume GNU make):

    shell$ make -j 4 all
    [...lots of output...]
    shell$ make install

Parallel make is generally only helpful in the build phase; the installation process is mostly serial and does not benefit much from parallel make.

## 5.1.3. `configure` options

There are many available options to `configure` (see `./configure --help` for a full list); a summary of the more commonly used ones follows:

- `--prefix=<directory>`: Install PMIx into the base directory named `<directory>`. Hence, PMIx will place its executables in `<directory>/bin`, its header files in `<directory>/include`, its libraries in `<directory>/lib`, etc.

- `--disable-shared`: By default, `libpmix` is built as a shared library. This switch disables this default; it is really only useful when used with `--enable-static`. Specifically, this option does not imply `--enable-static`; enabling static libraries and disabling shared libraries are two independent options.

- `--enable-static`: Build `libpmix` as a static library. Note that this option does not imply `--disable-shared`; enabling static libraries and disabling shared libraries are two independent options. Please see the Building Static Libraries section below for important details on building PMIx as a static library.

- `--disable-show-load-errors-by-default`: Set the default value of the `mca_base_component_show_load_errors` MCA variable: the `--enable` form of this option sets the MCA variable to true, the `--disable` form sets the MCA variable to false. The MCA `mca_base_component_show_load_errors` variable can still be overridden at run time via the usual MCA-variable-setting mechanisms; this configure option simply sets the default value.

  The `--disable` form of this option is intended for OpenPMIx packagers who tend to enable support for many different types of networks and systems in their packages. For example, consider a packager who includes support for both the FOO and BAR networks in their PMIx package, both of which require support libraries (`libFOO.so` and `libBAR.so`). If an end user only has BAR hardware, they likely only have `libBAR.so` available on their systems – not `libFOO.so`. Disabling load errors by default will prevent the user from seeing potentially confusing warnings about the FOO components failing to load because `libFOO.so` is not available on their systems.

  Conversely, system administrators tend to build an OpenPMIx that is targeted at their specific environment, and contains few (if any) components that are not needed. In such cases, they might want their users to be warned that the FOO network components failed to load (e.g., if `libFOO.so` was mistakenly unavailable), and thus some PMIx calls might unexpectedly return “not supported”.

- `--with-platform=FILE`: Load configure options for the build from `FILE`. Options on the command line that are not in `FILE` are also used. Options on the command line and in `FILE` are replaced by what is in `FILE`.

- `--enable-python-bindings`: Build the Python bindings for PMIx. Note the following packages are required to be installed:

      shell$ yum install Cython python3 python3-devel
      or...
      shell$ pip3 install Cython

Once OpenPMIx has been built and installed, it is safe to run `make clean` and/or remove the entire build tree.

VPATH and parallel builds are fully supported.

Generally speaking, the only thing that users need to do to use OpenPMIx is ensure that `<prefix>/lib` is in their `LD_LIBRARY_PATH`. Users may need to ensure to set `LD_LIBRARY_PATH` in their shell setup files (e.g., `.bashrc`, `.cshrc`) so that non-interactive SSH-based logins will be able to find the OpenPMIx library.

## 5.1.4. Building Static Libraries

PMIx depends on a number of external libraries for critical functionality. Some of these libraries, such as HWLOC, can have dependencies on a varying number of additional libraries (such as libpci or libudev). While PMIx’s wrapper compiler will add the correct direct dependencies for third party packages, it will frequently not pull in the right sub-libraries. When linking against dyanamic library versions of these dependencies, this is not a problem (and is preferred behavior to avoid adding unnecessary indirect linking dependencies). However, this does cause problems for building entirely static versions of PMIx. It may be necessary in some circumstances to add these dependencies via the `LIBS` environment variable (for building PMIx binaries) or `--with-wrapper-libs=LIBS` for the wrapper compiler.