Frequently Asked Questions

Is IUS a Rackspace service or product?

No. Rackspace is not obligated to provide support of any kind for IUS packages. Using IUS does not make you a Rackspace customer.

If you are a Rackspace customer, service level agreements (SLA) don't apply to IUS packages. Contact your account manager if you have further questions.

What is the relationship between Rackspace and IUS?

IUS is sponsored by Rackspace, but is not a service or product of Rackspace. It is similar to the relationship between Red Hat and EPEL.

Can IUS add a package for {software}?

It depends. IUS is not a general purpose repository. It has the limited scope of only providing newer versions of packages already in RHEL. If the software in question is not packaged in RHEL, then it is eligible to be submitted to the EPEL (Extra Packages for Enterprise Linux) repository, and is out of scope for IUS. If the software is packaged in RHEL (or EPEL) but is an older version, it may be a good fit for IUS. You can open a new package request on our wishlist.

How is IUS different from SCL?

IUS and Software Collections (SCL) both seek to solve the problem of providing optional newer versions of software for Enterprise Linux. They differ significantly in execution.

Most IUS packages are designed to safely replace their stock equivalent, but SCL packages are designed to be parallel installable with stock packages (and each other). This means that SCL packages must install to alternate paths such as /opt/, /etc/opt/, and /var/opt/. Most IUS packages can be used just like their stock equivalents, but commands from SCL packages must be used through the scl wrapper script. Daemons from SCL packages are named differently as well.

IUS packages follow upstream releases, but SCL packages have independent life cycles that may be shorter or longer than the upstream software.

Should I use IUS so I can pass a security audit such as PCI?

Some security audits only use software versions to confirm security vulnerabilities have been addressed. This approach does not take into account Red Hat's practice of backporting of security fixes. It is not recommended to use IUS packages just to pass a security audit.

How do I know when an IUS package is being retired?

Since IUS packages follow their respective upstream life cycles, they reach end of life (EOL) before the operating system and are retired. To be notified about package retirements (and other important announcements), watch our announce repository on GitHub.

Why do some IUS packages have a "u" suffix?

RHEL 5.6 (2011) added an alternate php53 package. This name conflicted with the existing php53 package that IUS was shipping. To prevent overriding a stock package, we renamed our package to php53u. Later we Red Hat announced SCL (2013), we were faced with several other naming collisions. To avoid confusion and possible yum mix ups, we started adding a "u" suffix to all our package names.

Red Hat quickly changed their SCL naming scheme and started prefixing all their SCL packages with "rh-". All of the conflicting SCL packages are now EOL. With this change, and Red Hat moving past SCL to modularity, suffixing our packages will likely never be necessary again. In 2018 we started created new packages without the "u" suffix.

How long do updates have to wait in the testing repository before being promoted to the main repository?

Updates for our existing packages are first released in the testing repository. If no issues are reported after one week, the updated packages will be promoted to the main repository. We reserve the right to promote package sooner if necessary.

This release policy does not not apply to new packages that have yet to be added to the main repository. When a new package is requested, the requester must agree to test the package. Once the requester confirms that everything works as expected, the package is eligible to be added to the main repository.

Why doesn't IUS have packages for RHEL 8?

RHEL 8 introduced Application Streams (also know as modularity). This gives Red Hat a way to provide optional newer versions of software. EPEL plans to give package maintainers the ability to offer additional streams that Red Hat doesn't offer. If this goes according to plan, IUS simply won't be necessary in RHEL 8 going forward.

Why am I getting errors about missing packages when using IUS on UBI?

UBI is container base image that only has access to a subset of RHEL packages. IUS is built for RHEL and CentOS. While some IUS packages may install with UBI, others will fail to install due to missing dependencies. If you would like to install IUS packages in a container, you will probably be better off using RHEL or CentOS base images. UBI package requests can be submitted through Red Hat support cases (customers) or bugzilla (non-customers).

Is IUS compatible with Amazon Linux?

No. IUS packages are built to be compatible with RHEL and CentOS. Amazon Linux is loosely based on RHEL, but diverges significantly and cannot truly be considered a RHEL clone. Other third party repositories such as EPEL face this issue as well.

Why does yum fail with conflict errors when installing a non-IUS package?

This can happen if the package you want to install has dependencies that could be satisfied by multiple IUS packages. Yum's dependency resolution is not always smart enough to pull in all the correct dependencies. You can work around this by explicitly requesting a few more package names to help the transaction resolve successfully. yum deplist <package> shows dependencies including alternatives.

Alternatively, you can install DNF, which has more sophisticated dependency resolution capabilities and can determine the right thing to do.

Why does composer fail to install with IUS enabled?

This is explained above. You can explicitly request these package names to help yum resolve the transaction.

  • yum install composer php72u-{cli,common,gd,intl,mbstring,pdo,process}
  • yum install composer php73-{cli,common,gd,intl,mbstring,pdo,process}
  • yum install composer php74-{gd,mbstring,pdo,process,pecl-zip}

Alternatively, you can use DNF. If you already have some PHP packages installed, it will resolve matching ones. If you don't have any PHP packages installed yet, it will resolve to the latest ones available to satisfy composer's dependencies. If you ask for any specific PHP package in your yum command, DNF will resolve the rest of the dependencies to match.

  • dnf install composer (with any other php package already installed)
  • dnf install composer php72u-common
  • dnf install composer php73-common
  • dnf install composer php74-common

I don't see php73 in the repos, where is it?

Traditionally in Red Hat and Fedora PHP packages, the php package contains the PHP module for the Apache HTTPD Server, commonly known as mod_php. The PHP language is packaged as php-common. This naming is confusing, but Fedora has declined to change it.

IUS decided to fix this in our PHP packages to reduce user confusion. We move the mod_php files into a subpackage such as mod_php73. When you want to use our PHP packages, you must explicitly choose the PHP SAPI (server API) you want, such as mod_php73 or php73-fpm.

Why can't I install mod_php71u with httpd24u?

mod_php compiles against the MMN (magic module number) of httpd. This means that if you build mod_php against httpd 2.2, it can only install with httpd 2.2. When we created httpd24u, we decided to continue building our mod_php packages against stock httpd. Building mod_php for every combination of php and httpd was far more complexity than we were willing to maintain. If you would like to use php71u with httpd24u, you must use php71u-fpm.

How can I report an issue with an IUS package?

If you think you've discovered a problem with an IUS package, please let us know. Locate the appropriate package source GitHub repository and open an issue. If you are familiar with RPM packaging and know what the fix is, you can send a pull requests. If the problem is with the software and not the packaging, we can usually assist in reporting it upstream. We also like to determine if Fedora is affected as well, and coordinate the fix there as well.

If the issue affects multiple packages, you may consider reporting it against our packaging meta repository. We also have an infrastructure meta repository for reporting infrastructure issues.

Why am I getting a GPG key error when I attempt to update my IUS package?

In 2019 the IUS project switched to new package signing keys. These are listed (along with our legacy key) here. Make sure your ius-release package is updated to at least version 2, then check in /etc/yum.repos.d/ for any *.rpmnew files that need to be merged. Then go subscribe to our announce repository on GitHub to be notified of changes like this in the future.

Where can I find packages for RHEL 6 and older versions?

RHEL 6 has reached end of life and is no longer receiving security patches. The IUS packages for RHEL 6 and older are not maintained and should not be used. For historical purposes, these packages are available at

Can I become an IUS mirror?

For many years we relied on a network of mirrors to distribute our content. Organizations would volunteer to mirror our content, and we would direct our users to them via our mirrorlist API. We referred to these as public mirrors. Some organizations only wanted to mirror our content for their own use and not serve it as part of the mirror network. We referred to these as private mirrors.

In 2019 we switched to using the Rackspace CDN. This means we no longer need public mirrors. If you would still like to mirror our content for your own needs (private mirror), you can use the following endpoints to bypass the CDN and sync straight from the source. Do not use these endpoints to directly consume IUS packages.

  • http:
  • https:
  • rsync: rsync://