RHEL6 « Luc de Louw's Blog

Posts Tagged ‘RHEL6’

RHEL6 as a web server

Sunday, May 2nd, 2010

New software versions

Today I’m writing about the changes and benefits of RHEL6 as a web server compared to RHEL5. Red Hat is well known for its stable API and ABI over the life-cycle of a major release. For some usage types this is a major problem. Sticking to old version of PHP, MySQL, Tomcat you-name-it-piece-of-software is problematic since web applications are rapidly changing its requirements.

Instead of PHP 5.1.6, RHEL6 ships almost up-to-date PHP 5.3.1. Which is good, since web applications such as TYPO3 require PHP 5.3 to be able to install security bug fixes.
The Apache httpd comes in Version 2.2.14 instead of 2.2.3. Since Apache is not very actively developed further, it does not matter anyway.
MySQL is shipped with an almost-up-to-date version 5.1.42 vs. 5.0.77. No big deal.
Tomcat is being installed with version 6.0.20 instead of the very old 5.5 in RHEL5. This brings quite some benefits for Java web developers.
Nothing has changed since RHEL5.5 so far for PostgreSQL. Since RHEL5.5 Red Hat ships version 8.4 in addition to 8.1.
Python got upgraded from 2.3 to 2.6 which probably allows to run more Python based web applications.
Unfortunately still no appearance of GraphicsMagick as a replacement for ImageMagick.
New: Ships with APC (Alternative PHP Cache). This is useful for LAMP servers with loads of traffic and helps to get response time below critical values.

Unlike other distributions, Red Hat’s default DocumentRoot is still in /var/www instead of /srv/www. From my point of view the /var should be used for libraries and similar stuff, but not for application data. This ends up in creating symlinks like it was before.

From the “I-dont-like-bloated-systems” Departement

Looks like Red Hat made a huge progress in making its system less bloated. In Versions up to RHEL5 you can experience strange package dependencies.

PHP and friends: While on RHEL5 a “yum install php” automatically selects PostgreSQL-libs and gmp to install, nothing like this happens on RHEL6.
Tomcats dependencies went down from 48 packages to only 15.

Conclusion

At the end of the day, Red Hat made a good job to enable RHEL as a web server again. The fundamental problem is still the same: In two years RHEL6 will be completely outdated and not useful for modern web application, like it is today with RHEL5. Of course you can compile the stuff by yourself, but then you’ll get a maintenance problem.

Red Hat should think about something similar like Debian’s “volatile” repository. It provides upgraded software which would otherwise be useless in a two years or older versions. I’m looking forward for a “Red Hat Volatile” Channel on our satellites.

Feedback is welcome…

Have fun!

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Tags: Apache, RHEL, RHEL6
Posted in Linux, Red Hat, Uncategorized, Web Servers and Applications | 5 Comments »

A brief test of RHEL 6 Beta 1

Friday, April 23rd, 2010

As promised yesterday, I publish the results of a brief test of RHEL6 Beta 1 and the most important findings. It is my point of view as a system guys daily business. If not stated, this overview is based on a default installation with no customization.

General

There are new package groups such as “Minimal” with 228 Packages and “Basic Server” with 523 Packages. “Basic Server” is the default installation, which means the default click trough installation compared to RHEL5 is much less bloated.

The versions of the most important software is quite up-to-date but as expected not on the bleeding edge.

ext4 is the default file system. Hopefully the fsync issues are solved. See more here: http://lwn.net/Articles/322823/

Postfix is the default MTA. Finally Red Hat managed to switch away from sendmail like other distributions did it years ago.

Bye bye SysV init: As I guesstimated in october 2009 RHEL6 comes with upstart instead of traditional SysV init. (See http://blog.delouw.ch/2009/10/31/ready-to-upstart/). The boot process is much faster compared to RHEL5. Upstart comes with legacy support for traditional runcontrol scripts in /etc/init.d.

Still too many services enabled after default install. Generally unneeded services like avahi/mDNS and NFS-related daemons such as portmap are still enabled by default.

Virtualization

As expected, Xen was removed completely from RHEL6. These is being discussed controversial. Why not providing both virtualization solutions as before? Recently Citrix released Xen4 which works well together with Kernel 2.6.32, the same version as used by RHEL6.

KVM and its friends made a huge step forward. lib-virt, virt-manager and stuff is nearly up-to-date with the upstream versions. Means: The virtualization infrastructure made a lot of progress. Installing RHEL6 as a KVM guest works great. All drivers needed (virtio) are automatically installed.

A major good message to people which are using VMware vPhere 4 is that RHEL 6 comes which native support of vmxnet3 which was obviously backported from Kernel 2.6.33. Vmxnet3 is the driver for VMware’s para-virt NIC which brings quite some performance enhancements and lower CPU usage on the ESX host.

Certifications from ISVs

A quick check (not actually tested) for the requirements for SAP and Oracle shows that those are fulfilled already. We can expect the certification quite soon after GA of RHEL6. [update] Some compatibility RPMs from the mid 1990′s disappeared. I now need to figure out if they are *really* needed by Oracle and/or SAP[/update]

Integration with Cobbler

Integration with cobbler works like expected, cobbler import –path=/mnt –name=rhel6 and you are done. For a quick test I just copied the kickstart template from RHEL5 and I’m not sure if this is a good method. A test-install on ESX4 failed, the system hung at the creating of the root-VG. Not sure yet if it is a bug or something is incompatible in the kickstart. [update] The system hung was because of out-of-memory. The test-installation was on a ESX guest with 384Mbyte of memory which is enough according to the documentation but too little in real life. Growing the RAM of the test system to 512Mybte helped, but some packages needed by for SAP have changes names or disappeared. After changing/removing those RPMs, the installation went smoothly[/update]

Bugs or features?

I detected some oddities where I’m not sure if it is a bug or a feature. We will see whats going on on http://bugzilla.redhat.com.

No network configured after default install. At the moment you need to configure it manually (considered a Bug)
I detected a major security issue during install, I’m not going to disclose it before a patch is available or more information from Red Hat is made available. I reported it 2010-04-23 ~12:00 on Red Hats bugzilla bugtracker. [update] The bug gots assigned to a Red Engineer after three hours, seems like Red Hat is acting very professional on the case[/update]

Conclusion

After this brief test one can say that RHEL6 will be a really great Linux Distribution for enterprise servers. The beta is already very stable with few bugs detected from my side. My guesstimate is that mid of May 2010 there will be a second public beta released, lets stay tuned, I’ll keep you up-to-date with further findings.

Have fun!

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Tags: ESX, Linux, RHEL6, Upstart, Virtualization
Posted in Linux, Red Hat, Virtualization, Web Servers and Applications | 3 Comments »

RHEL 6 public beta released

Thursday, April 22nd, 2010

Red announced the first public beta release of its next Enterprise Linux.

It can be downloaded at Red Hats FTP Server.

You can expect a brief test later this day.

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Tags: Linux, RHEL6
Posted in Linux, Red Hat | Comments Off

Roadmaps on the Red Hat Summit 2010 in Boston

Monday, March 15th, 2010

Finally Red Hat disclosed the agenda of its summit in 2010. For more informations see http://www.redhat.com/promo/summit/2010/agenda/.

RHEL6?

Tim Burke of Red Hat will talk about the new features of RHEL6. It sounds like the present, not the future. Does this mean I’m right with my guess that RHEL6 will be released end of June like I wrote in earlier blog article?

Roadmaps

Count how many times the word “Roadmap” appears in the agenda. It seems to get even more interesting what Red Hat plans to do. But it is still unsure what kind of new features we can expect in RHEL6. Red Hat just disclosed some snippets of RHEL6 again, this is called Salami-Tactic.

Where is the commitment?

We (the RHEL community) are still missing a clear commitment to us as customers. Only little is known about RHEL 6

Love or hate?

Should the RHEL community love or hate Red Hat? At the end of the day I like Red Hat, they do a lot for the progress of Linux in general and Linux in enterprises in particular. Anyway: Not providing a roadmap makes me and possibly others too very angry. Such a roadmap does not need to necessarily be in detail.

Have fun! Really? Soon we will have!

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Tags: Linux, Red Hat, RHEL, RHEL6
Posted in Linux, Red Hat, Virtualization | Comments Off

Kernel questions about RHEL6, ESX support and experiences with F13a3

Monday, March 15th, 2010

Still no official informations

Red Hat is still refusing any questions about the features of RHEL 6 and its Linux Kernel. However: Since Vanilla Kernel 2.6.33 vmxnet3 and pvscsi is supported. Fedora 13 Alpha 3 is shipped with a derivate of Kernel 2.6.33.

I still hope that Red Hat is switching to 2.6.33 or back-porting the VMWare code to its 2.6.32 derivative Kernel as known by RHEL 6 Alpha 3.

Experiences with F13a3 so far

Installing F13a3 on a ESX guest – with RHEL5 as “supported Guest OS” – and enabled vmxnet “enhanced” plus pvscsci as HBA was a smooth experience. No driver disk was needed, no dirty fixes. Just selecting vmxnet3 as NIC and PVSCSCI as disk HBA. Thats the way RHEL6 should work from my point of view.

RHEV vs. VMWare ESX

Since Red Hat released its visualization solution “RHEV”, VMWare and Red Hat are competitors. Is Red Hat willing to include ESX support in its Enterprise Products? My guess is to not to do so, but I’m open for surprises.

The goals

The goal on the long term is to switch from ESX to KVM. However, if you deployed a large ESX farm already and the management members are members of the “ESX-Church” it will be hard.

The mid-term goal is to get rid of those crappy VMWare tools. The current state of this “Tools” definitively proves that VMWare is a Windows shop and does not take care about Linux virtualization.

Will we have fun? Depends on EMC and Red Hat….

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Tags: ESX, KVM, Linux, RHEL, RHEL6, Virtualization, VMware
Posted in Linux, Red Hat, Virtualization | Comments Off

Where the heck is RHEL6?

Sunday, February 28th, 2010

Release cycle slowed down

In the past Red Hat has released a new version of its Red Hat Enterprise Linux (RHEL) roughly every two years. RHEL5 was released on march 2007. Compared to the past release cycle, RHEL6 is overdue since one year.

Official information

There is only little known about the upcoming features of RHEL6. On the Red Hat Summit 2009, there was a presentation held by Tim Burke which gives just some hints that RHEL6 is actually approaching, see http://www.redhat.com/f/pdf/summit/tburke_1050_rhel_roadmap.pdf. Quoting a note on the slide about RHEL6: Note: this information is high level planning projection and does not constitute formal product commitment.

My conclusion is that Red Hat seems to be unsure about the features planned for its upcoming Enterprise Product.

Another interesting quote from the same presentation is: RHEL6 feature previews – appearing in Fedora 11 & 12. Meanwhile, almost a half year later, Fedora 13 is approaching and still no sign of RHEL6, no schedule, no official feature list. Looking at the feature list if Fedora 13 https://fedoraproject.org/wiki/Releases/13/FeatureList, nothing special so far. It seems that the pace of development has been slowed down a bit to put more energy into stabilizing F11/F12 to RHEL6.

Inofficial information

When carefully watching git commit logs and bugzilla entries, there are some small traces of RHEL6.

There is almost no information leaking for the topic. The only valuable unofficial information is from bug #562766 which was reported by a Red Hat employee on 2010-02-08. This bug states RHEL6 Alpha3! Quoting a comment from the same employee: Upgrading rhel6.0 kernel to 2.6.32-14.el6 fixes the issue.

this brings me to a wild guess for a release schedule:

February 2010: Alpha3
March 2010: Beta1
April 2010: Beta2
May or June 2010: GA [Update: End of June/Early July seems to be more likely, since the Red Hat Summit will be held June 22-25 2010]

My wish list for RHEL6

Kernel based on version 2.6.33 instead of 2.6.32 as in Alpha3, since there are a lot of improvements when using RHEL as a VMware ESX guest.
Default installation with a smaller footprint
Cleanup of insane package dependencies
BusLogic drivers included as the vanilla Kernel ships it since years

The question remains

Where the heck is RHEL6? One reason could be that the focus on RHEL6 seems to be virtualization and system management. Since approximately two years, in this domain the pace of the development had increased a lot, maybe too much. Think about KVM, libvirt, virt-manager, o-virt. All of those projects are sponsored by Red Hat and included in F12. So one of the reason of the late release of RHEL6 can be problems in stabilizing those virtualization products to be enterprise-ready.

Why Red Hat makes its customers angry with late releases and no roadmap

First of all, RHEL products have a life-cycle of seven years. RHEL5 was released on march 2007. Assuming RHEL6 will be GA on May 2010. Add a few months before it is supported by ISVs such as SAP, Oracle etc. Customers can begin with deploying RHEL6 on lets say August 2010. Until then, RHEL5 has almost reached half of its life-cycle: 3 1/2 years. Means: A SAP system deployed on July 2010 is out of support some 3 years and nine months later. For an enterprise product this not acceptable! Red Hat should think about a life-cycle like “Next-Release plus five years“, this would make system deployment and company-internal life-cycle management easier.

Keeping its customers in the dark with no official roadmap at all is just bad behavior and indeed not customer friendly.

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Tags: KVM, Red Hat, RHEL, RHEL6, Virtualization
Posted in Linux, Red Hat, Virtualization | Comments Off

Ready to upstart?

Saturday, October 31st, 2009

It is time to replace the aged SysV init system with someting better

At the time when SysV init (pronounced “System five”) appeared, hardware configurations have been quite static, no hot plug and similar fancy stuff.

SysV init is started after the kernel is loaded. The init process reads /etc/inittab and walks trough the runcontrol script and runlevels. This sequential walk-trough takes most of the time when booting a modern Unix system.

Upstart follows another approach: Starting daemons and services in parallel and event driven. This will speed up the boot process beyond expectations.

A very nice feature of upstart is: All processes will be started in background, no more blocking of the boot process trough hanging run control scripts!

If a service unexpectedly dies, it will be respawned automatically up to a configurable limit in times per period.

Upstart is event-driven, a event can be e.g. plugging in new hardware which ends up starting the needed service for it. There are also plans to replace cron and atd with upstart since this are basically time-triggered events. The developers also thinking about replacing the inetd, since a network connection can be considered as a event.

Transition

Since most of the software out there do not natively support upstart yet, transition methods are needed for a smooth transition from SysV init to upstart. Traditional SysV run control scrips are fully supported, even distributions slowly switch to the event/job model of upstart. E.g. one of the first distributions switched to upstart was Ubuntu 6.10, and now with Ubuntu 9.10 – three years later – they begin to ship its distribution with the first native upstart scripts.

Splitting Unix systems apart

Years ago there only have been two init systems: SysV init and BSD init, a sysadmin was comfortable to use them on whatever system. Now there are SysV init, Upstart from Ubuntu, lauchd from Apple, SMF (System Management Facility) from Sun Microsystems and possibly others. All of this SysV init replacements are working differently, different commands, different architecture… This makes the job of a sysadmin not easier when managing a heterogeneous system landscape.

Linux distributions stay together

The good news: On the Linux side it looks like Upstart will be the future standard for system initialization, no balkanization of the Linux Landscape so far.

Linux Distribution with upstart

The following distributions are already shipping upstart:

Ubuntu
Debian
Fedora
Others?

Since Fedora 11 and 12 will be the upstream for the upcomming RHEL6 distribution it is most likely that RHEL6 comes with upstart. At openSUSE there are some discussions (see https://features.opensuse.org/305690 for details). Maybe there is a chance for openSUSE 11.3 and later on SLES12.

Luc de Louw's Blog

Posts Tagged ‘RHEL6’

RHEL6 as a web server

A brief test of RHEL 6 Beta 1

RHEL 6 public beta released

Roadmaps on the Red Hat Summit 2010 in Boston

Kernel questions about RHEL6, ESX support and experiences with F13a3

Where the heck is RHEL6?

Ready to upstart?

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