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License: MIT

CentOS Logo

This Guide is for CentOS Linux Operating System

Packages can be installed using RPM or YUM. YUM is preferred and easier because it handles package dependencies. A useful resource for information about available packages is https://centos.pkgs.org/

Before starting, we should verify what repositories are available to us.

# yum repolist

If not already available, we should add the following repositories for Enterprise RHEL release packages (Red Hat Enterprise Linux):

  • EPEL (Extra Packages for Enterprise Linux)
  • REMI-Safe (French guy named Remi - contains packages that are now deprecated)
  • ELRepo (Enterprise Linux Repository)

The REMI repository consists of multiple repos, and by default they are all disabled except for remi-safe. It's a good idea to enable the remi-phpxx repo for the specific PHP version running on the server as they will typically have more recent package updates compared to CentOS base repositories. To list all available installed repositories and enable/disable them:

# yum repolist all
# yum-config-manager --<enable|disable> remi-phpxx

It is recommended to try installing default "single" version packages if possible, as this will require less maintenance and additional installation steps. Default packages usually follow the naming convention of php-xxx. You can check whether a package installs to default locations or not using the repoquery tool (yum-utils package). See the Installation Notes below for more details.

We can search for a package by string from all available repositories. If there are a lot of repositories enabled, it may be more useful to restrict searches to only repositories with Enterprise packages (if the package we want is not found, only then search all available repositories, omitting the optional parameters relating to repo).

yum search --disablerepo=* --enablerepo=epel <string>

If anything is found, a list is returned showing full package names with a 1-line description. The list may contain a few different versions of what we're looking for so it's a good idea to use the info command get more information about packages. The string parameter for this command tries to match by exact package name, so it's more useful to provide wildcards for multiple matches.

yum info --disablerepo=* --enablerepo=epel *<string>*

To install a package, and automatically try installing any dependency packages. It will ask show a confirmation, detailing what package and dependencies will be installed:

yum install <package_name>

Some packages may require a specific version of a package (older one to currently installed) and fail to install the original package you requested as a result. Check all the error messages to see if this is the case - if so, we can try to force installation and ignore the requirement for older package versions.

Keeping Packages Up-to-date

By enabling the relevant remi-phpxx repo, you can easily keep your packages up to date simply by running the command (httpd would normally need to be restarted for changes to be applied):

yum update

Installation Notes

The standard installation locations are:

/etc/php.d/ (ini) /usr/lib64/php/modules (default so module)

Non-standard php packages are installed in different locations (ini and so files). To enable this extensions to load, create symbolic links for the files in the appropriate default locations (ln -s <source> <destination>). Non-standard installation paths

/opt/<vendor>/<package-name>

To find out where the files of a package are installed to, run the command repoquery -l <package-name>.