Red Hat Enteprise Linux roadmap: Summit Q&A

If you attended the Red Hat Enterprise Linux roadmap session at this year’s Red Hat Summit, you saw it was a packed house with a lot of great questions. And now that Red Hat Enterprise Linux 7 is generally available, we want to provide even more explanation and details on questions asked by attendees.

Check out what attendees wanted to learn more about – sorted by topic – in the 2014 roadmap session below. You’ll also find links to additional information where available. In case you missed it, you can download the presentation slides here.

RED HAT ENTERPRISE LINUX 7

Q: You select the packages based on popularity. But do you have a limit on how many packages you give support? Does this limit grow or decrease over time?

A: We select packages based on what enterprise customers need to support their environments; we do not have a set limit or target number of packages. If you have a need for a specific package, we suggest that you file a feature request for us to review. Here’s the link of the customer portal to file a feature request:  https://access.redhat.com/site/solutions/73513

Q: How does Red Hat leverage relationships with other vendors such as SAP and Oracle? Are these vendors already working to make their software Red Hat Enterprise Linux 7 compatible?

A: Red Hat works with many ecosystem partners to certify that their products work well with all of the products in our portfolio.  In order to increase reach beyond what we can accomplish on a one to one basis, we invite ecosystem partners to participate in one of our many partner programs. For those we cannot reach directly or through one of these programs, we make betas publicly available for them to download and test with.

Q: Does HERM support include Power and s390 platforms?

A: At present HERM is supported on x86_64 on Red Hat Enterprise Linux 7.

Q: Do you foresee any issues with Red Hat Enterprise Linux 7 supporting current Java apps such as JBoss 6?

A: OpenJDK 7 is the system default Java SE compliant runtime available in Red Hat Enterprise Linux 7.   In addition to being available in Red Hat Enterprise Linux 7, OpenJDK 7 can also be installed in Red Hat Enterprise Linux 5 and 6.   While there are no technical issues preventing applications from running on Red Hat Enterprise Linux 7 using OpenJDK 7, customers are advised to consult the respective third-party ISV application support matrices to ensure that their application is supported in this configuration.

JBoss EAP 6 running on OpenJDK 7 and Red Hat Enterprise Linux 6 is available as a supported configuration today[1]. Please contact Red Hat Global Support Services for information on availability of JBoss EAP on Red Hat Enterprise Linux 7 as a supported configuration.

Red Hat recommends that customers not deploy Java applications on Red Hat Enterprise Linux 7 if they are designed to run on Java 6 (or earlier versions of Java.) Java 6 is available in Red Hat Enterprise Linux 7 for legacy applications that are self-contained and have no dependencies on system Java packages.
[1] https://access.redhat.com/site/articles/111663

Q: Will DTrace be in Red Hat Enterprise Linux 7?

A: SystemTap on Linux provides similar capabilities to DTrace. If you are familiar  with DTrace, and have existing DTrace scripts, you can use the following URLs to convert them into equivalent SystemTap scripts and find helpful examples:

For a complete guide on SystemTap consult: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/SystemTap_Beginners_Guide/index.html

Q: Why was Thunderbird removed as a mail client?  For desktop users, what are the endorsed alternatives, and what benefits do they offer?

A: As part of the package selection process, Red Hat evaluates the health of a project and looks for an active community to help address and accept bug fixes and security errata, as well as to provide continuous improvement with regards to functionality.  With the support for this project becoming limited, we elected to not include Thunderbird at this point in time.  Red Hat Enterprise Linux 7 will deliver Evolution, which has been delivered with Red Hat Enterprise Linux 5 and 6, as it is still an actively maintained project.

Red Hat continues to evaluate Thunderbird for inclusion in Red Hat Enterprise Linux 7 and may include it in a future release. Users who wish to use Thunderbird today are encouraged to download and install Thunderbird from Fedora EPEL 7.

RED HAT ENTERPRISE LINUX 7: CONTAINERS

Q: Believe it or not we have legacy Red Hat Enterprise Linux 4 applications that we can’t move off… yet.  Could they be put into a container?

A: We do not plan to support Red Hat Enterprise Linux 4 as a container format.

Q: Can I limit the CPU usage of all processes except login on terminals using containers? In my environment today I sometimes find a virtual machine stuck at 100% CPU utilization – due to a Java process – and can’t login to see what is happening! Note: we use LDAP-AD authentication… which may be why login doesn’t work.

A: Yes, you could do this with cgroups.  As containers are built by using various control groups  features, and in that two of the control groups, namely CPU and CPUSETS, are specifically designed to limit CPU usage on the processes inside a control group, you will be able to limit CPU usage by processes inside of a given container.  In greater detail, you could limit CPU usage by either limiting the logical CPU(s) that the process can be scheduled on or by limiting the amount of the time that a process can schedule/use a particular processor.  As for the run-away Java application in a virtual machine that eats up all CPU cycles… another way to access this system when this happens is to enable the sched_autogroup parameter:

bash# echo ‘1’ > /proc/sys/kernel/sched_autogroup_enabled

This will automatically configure the Linux  feature (cgroups) to group together related processes so that, under heavy load, certain processes still remain performant under the kernel scheduler. It allows a user login session to be free from the run-away cpu/memory process and allows an administrator to get into the system (…and kill  the run-away app). Also, for OpenJDK instances, we recommend you take a look at Thermostat, which is available via RHSCL 1.1. Thermostat will allow you to monitor, instrument and manage the resources associated with a running JVM on a physical, virtual, or cloud instance of Red Hat Enterprise Linux.

Q: How do containers functionally differ from Solaris zones?

A: Containers are conceptually similar to Solaris zones.  Containers, however, are implemented differently via different kernel and user space components in Linux.  The four parts to obtain a container environment are (1) control groups, (2) namespaces, (3) SELinux, and (4) systemd.  Control group and namespaces are implemented in the Linux kernel and exported to the user space.  SELinux (in the user space) provides security and access control for the processes inside the container and systemd provides the user space management infrastructure for the setup and tear down of the containers (in conjunction with Docker). Docker itself acts as the user interface to help create and launch applications inside of a container.

RED HAT ENTERPRISE LINUX 7: FILE SYSTEMS AND STORAGE

Q: Why is XFS the default file system in Red Hat Enterprise Linux 7?

A: Given the growth of data and file sizes, we felt it was important to introduce a scalable file system that can also handle large files, which is what XFS delivers.  We are still providing  full support for ext4, along with enhancements in the size of the files and the file system itself– a limit of 50TB which is up from the 16TB limit in Red Hat Enterprise Linux 6.  Customers can change the default to use whichever file system best satisfies their business needs.

Q: Are there any enhancements under Red Hat Enterprise Linux 7 to recover read only file systems without needing to perform a host reboot?

A: There are no changes in this area in Red Hat Enterprise Linux 7. For a non-root file system, you can unmount, complete the required admin tasks (to fix the file system), and mount it again. For a root file system you will likely need to reboot (possibly to single-user mode) in order to repair possible file system corruption.

Q: Can partitions be re-sized with or without downtime when needed?

A: Yes, you can re-size partitions; refer to the Storage Administration Guide. The guide explains that re-sizing can be done without a reboot if you unmount any partitions on the device and turn off any swap space on the device.

Q: With respect to file systems, are there any new features to help with the configuration of NFS4 with Kerberos?

A: Yes. We now have tighter integration with Red Hat Enterprise Linux Identity Management (IdM) services. Please refer to Steve Dickson’s Evolving & Improving Red Hat Enterprise Linux NFS presentation for additional information.

Q: What about an interface to setup a clustered NFS or any clustered file system?

A: This is under active development, based on the new capabilities of Pacemaker in Red Hat Enterprise Linux 7. Keep an eye out for new features in this area in future releases.

RED HAT ENTERPRISE LINUX 7: INSTALLATION

Q: Minimal install – why does this include infrared utils, cd writing tools, Bluetooth tools, etc.? I consider these bloatware for headless servers.

A:  The minimal install is the smallest recommended environment suitable for general use. For a smaller, but still relatively functional environment, use the @Base  group in a kickstart file. For an absolute bare-bones installation set, use the @core package group which is a subset of @base.

Q: Does the improved text mode installer interface include VTY support on Power systems?

A:  Yes.  Note however that terminal multiplexing during installation is provided by tmux; the VTY device should be fine to run the text mode installer.

Q: About the installer… As of Red Hat Enterprise Linux 5, the ability to install on a server via serial
console was made inoperable. This was not fixed in Red Hat Enterprise Linux 6. In order to install, I have to make custom boot images with hacked syslinux options. Is this fixed in Red Hat Enterprise Linux 7, or perhaps there are plans to fix this?

A:  The revamped text mode in the Red Hat Enterprise Linux  7 installer makes it more suitable for serial consoles.

RED HAT ENTERPRISE LINUX 7: INTEROPERABILITY

Q: Are there any new features to support Microsoft Windows integration like integrating with Active Directory, user accounts, shares and such?

A:  In addition to the SAMBA and CIFS support, Red Hat Enterprise Linux includes updates to LibreOffice which will facilitate file sharing via Sharepoint, an update to Evolution that can integrate with Exchange Server and support calendaring across a heterogeneous environment, enhancements to Identity Management for easier integration with Active Directory as well as a cross realm Kerberos trust model for easier interoperability between Active Directory and LDAP.

Q: Does Red Hat Enterprise Linux 7 Desktop support authentication of Active Directory Smartcard only accounts?

A:  Yes, this should work fine via pam_pkcs11 and pam_krb5.

RED HAT ENTERPRISE LINUX 7: NETWORKING

Q: What are the differences between network bonding and teaming?

A:  Team Driver is new for RHEL 7 and provides a mechanism to team multiple network devices (ports) into a single logical interface at the data link layer (Layer 2).  This is typically used to increase the maximum bandwidth and provide redundancy.

Even though this capability is similar to the existing Linux kernel bonding driver, the Team Driver project doesn’t try to replicate it and instead solves the same problem very differently using a modern, modular user-space based controlling approach.  Only the necessary data fast-path parts are found in the kernel and the majority of the logic is implemented as a user space daemon.  This approach provides a number of advantages over traditional bonding including more stability, easier debugging, and much simpler to extend while still providing equal or better performance in some cases.

Team Driver supports LACP (IEEE 802.3ad) and can be managed from either NetworkManager or the traditional network initscripts infrastructure.

RED HAT ENTERPRISE LINUX 7: UPGRADE / MIGRATION

Q: We are still on Red Hat Enterprise Linux 5, and have around 300 systems… is it worth migrating to Red Hat Enterprise Linux 6 now, or should we wait and move directly to Red Hat Enterprise Linux 7?

A: Our general recommendation is to use the most recent version of Red Hat Enterprise Linux for maximum performance, stability, features and hardware support.

Q: I understand that upgrading from Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 6 is unsupported.  Does the existence of an ‘upgrade assist’ feature in Red Hat Enterprise Linux 7 suggest that Red Hat will support and upgrade from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7?

A: Yes, with certain limitations. For more information, refer to this knowledge base article at the Red Hat Customer Portal.

Q: What about an upgrade assistant from Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 7? Context: enterprise customer with significant inertia / resistance to change. And will Red Hat Enterprise Linux 7 support in-place migration from Red Hat Enterprise Linux 5?

A: We have investigated this and determined that there are a large number of incompatibilities between the two releases and that an in-place upgrade will result in a customer having to perform a significant amount of clean-up.  That being said, we are investigating what we can do with the pre-migration assistant tool to help customers plan a migration from Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 7.

RED HAT ENTERPRISE LINUX 7: VIRTUALIZATION

Q: Are there any new features to integrate Red Hat Enterprise Linux and VMware and vCenter?

A: Red Hat Enterprise Linux has been supported as a guest on VMware since Red Hat Enterprise Linux 4; Red Hat Enterprise Linux 7 will be supported as a guest on VMware.  In addition, Red Hat has collaborated with VMware to have openvm-tools added to Red Hat Enterprise Linux 7. Openvm-tools was designed to simplify the deployment of Linux guests in a VMware environment. For addition information visit: http://open-vm-tools.sourceforge.net/

Q: Is NPIV supported in KVM?

A: NPIV is supported with KVM. For additional information on how to setup NPIV with libvirt, visit: http://wiki.libvirt.org/page/NPIV_in_libvirt

Q: Will Red Hat Enterprise Linux 7 x86_64 host support an IA64 Red Hat Enterprise Linux 5 or IA64 Red Hat Enterprise Linux 6 guest?

A: No, Red Hat Enterprise Linux 7 with KVM will only support x86_64 guests. KVM is a virtual machine hypervisor, not an emulator. The Red Hat Enterprise Linux virtualization support matrix may provide you with additional insight.

Q: Will the utilities for upgrade from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 work if Red Hat Enterprise Linux is a guest that resides on vSphere?

A: Yes. You should be able to upgrade a Red Hat Enterprise Linux 6 guest to a Red Hat Enterprise Linux 7 guest.

RED HAT SATELLITE

Q: We have six Red Hat Satellite servers and we’re about to build the seventh – all are disconnected – my Q: how do we synchronize the channel dump ISOs we download from access.redhat.com?

A:  If you need to update channel content to Satellite servers which cannot connect to each other the best option is to mount the content ISOs locally by:

  1. Loading the initial content ISOs downloaded from the Customer Portal and mounting to a drive which can be used local to each Satellite. Click here for access to documentation on how to mount the individual ISOs into a directory and to run the  ‘satellite-sync -m /path/to/mount-point -c <name of channel>’  command to sync the channel content.
  2. Once a Satellite has finished the initial sync of channel content, the channel content can be updated periodically by using the Incremental Content ISOs found on the Customer Portal. Click here to review example Red Hat Enterprise Linux 6 64-bit Satellite 5.5 incremental content ISOs.

You can also find more info in this kbase article:  https://access.redhat.com/site/solutions/367603

MISCELLANEOUS

Q: Where can I get the SELinux coloring book?

A: You can download the PDF and browse the source here. If you find any errors or issues, you can even submit a patch and git pull request!