March 20, 2011
"PowerStack is a repository that allows you to run the latest LAMP versions in your Enterprise Linux. Currently both CentOS and RHEL are supported (i686 and x86_64)."

—

From PowerStack site.

This is a brand new repository providing an up to date LAMP experience in your RHEL and CentOS based servers. Basically you can enjoy the long time support and API/ABI stability provided by Red Hat rock solid operative system, and at the same time have access to the cutting edge of the LAMP platform thanks to a trusted third party repository.

All the magic involved in the package creation is open source (there’s a git repo with patches and specs), and it’s now in my list of essentials for CentOS, read: EPEL, DAG, PGRPMS and Remi.

I must say that Remi is providing some of the LAMP stack components for some time (and I love Remi’s work, I’m enjoying some of his packages for Fedora 14, such as Firefox 4), but this PowerStack repository it’s specifically focused on enterprise server environment (they’re supposed to be very picky with the dependencies, which is good in a server!).

by jjm on 8:08pm  |   URL: http://tmblr.co/ZPorZy3jhmAR
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(Notes: 20)
  
Filed under: CentOS RHEL PowerStack repository repo LAMP MySQL PHP Apache Fedora 
March 22, 2010
Sendmail’s Mailertable and Backup MX

When a backup MX server is setup, it’s needed to configure the destination server for the domain being backed up.

For example:

domain.tld.            172800	IN	MX	10 mail.domain.tld.
domain.tld.            172800	IN	MX	20 backup.domain.tld.

In our mailertable we have:

domain.tld     esmtp:[mail.domain.tld]

Simple, isn’t it? We’re using the brackets to avoid MX resolution, and hence undesirable loops because we’re in the MX records ourselves (backup.domain.tld).

But, What if the master server has two 10 MX records to load balancing? We can’t remove the brackets because of a possible loop… Sendmail has two solutions (although not very well documented).

Simulate MX Failover

Setup different servers separated with :, for example:

domain.tld     esmtp:[mail1.domain.tld]:[mail2.domain.tld]

When mail1.domain.tld fails, mail2.domain.tld is used.

Simulate DNS Round-Robin

Setup different servers separated with ,, for example:

domain.tld     esmtp:[mail1.domain.tld],[mail2.domain.tld]

The mail submittion will be balanced between the provided servers.

Final Rant

It would be great if mailertable documentation was more complete. Sometimes is very difficult to find this kind of information, because the mailing lists aren’t as easy to find with Google as used to.

by jjm on 4:08pm  |   URL: http://tmblr.co/ZPorZyRn48y
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Filed under: Sendmail CentOS mailertable round-robin Failover MX backup 
January 5, 2010
Change the Queue Runner Interval in Sendmail

The default in CentOS 5.x is 1 hour:

# pgrep -lf "Queue runner"
12443 sendmail: Queue runner@01:00:00 for /var/spool/clientmqueue

You can change it editing /etc/sysconfig/sendmail (ie. set 30 minutes):

DAEMON=yes
QUEUE=30m

It’s easy, isn’t it? Useful for mail backup MXs that may need shorter queue run times.

by jjm on 9:28am  |   URL: http://tmblr.co/ZPorZyIyXyi
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Filed under: Sendmail queue queue run CentOS 
November 25, 2009
Being Busy

I’m in the last stage of a 30 hours course I’m giving in sanidad (more precisely the department of health care of Valencian Community), and it’s requiring all my time and energy.

The attendees are government employees and, to my surprise, they’re very interested in the course: Linux administration.

Basically I’m trying to give a crash course to administering Red Hat Enterprise Linux 5 (eh, CentOS 5), without going too deep (skip SELinux!), but scratching the surface enough to let them make interesting things (use GUI tools as much as possible it’s a good rule of thumb).

Overall I think they’re very satisfied with the contents so far, and I like teaching, but I’m not a teacher in my everyday job: I don’t have enough stuff such as slides, laboratory exercises, etc; and that’s why I’m so busy and it’s being so exhausting.

Moreover it’s a very nice opportunity to do FOSS advocacy, and I’m trying to make most of it!

by jjm on 9:16am  |   URL: http://tmblr.co/ZPorZyFJRjU
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Filed under: CentOS RHEL teaching course 
July 14, 2009
Strategy for Windows Desktop Replacement

I’m partially involved in a project that aims for the full replacement of Windows as a desktop OS in a BIG institution in the autonomous goverment in Valencia. Although I don’t want to give too much details by now, I’ve proposed to the project manager a strategy based on Fedora/CentOS/Red Hat.

The main problem of a big institution is there are several kinds of desktop users (and desktop needs). In a first approach we’ve defined three variables:

  • Features: Do we need the shiny new features of the desktop world, or can we live with outdated (but stable) applications? In this variable Fedora is a big winner as a cutting edge distribution.
  • Stability: I know that new applications can be stable enough, but for the user that only does ‘1, 2, 3’ every day, it doesn’t matter if there’s Firefox 3.5 or 1.5. We want stability and support as long as possible without upgrading. Here I suggest CentOS.
  • Support: Sometimes the work in a desktop is critical and we may need paid support, and Red Hat has a good reputation for our customer, so RHEL is the best choice.

Another big problem is the number of desktops, and a nice tool to help administrate all the computers would be a good point for the proposition (we’re providing solutions, not new problems heh).

The bonus is that we can manage all three distributions with Spacewalk (or Red Hat Network Satellite, although the reason behind the desktop migration is money), and the customer loves the idea of a three level solution related to the same vendor.

I’m optimistic about this project, and customer feedback it’s also good, so I’ll keep you informed.

by jjm on 4:04pm  |   URL: http://tmblr.co/ZPorZy8RmM6
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(Notes: 1)
  
Filed under: Fedora support desktop CentOS RHEL 
June 26, 2009
CentOS Server Install

I know I’m an old-school system administrator, who doesn’t want a X session running on his servers.

The Console and the CLI are the ultimate tool for a sysadmin (In the Begining was the Command Line), and I don’t like the extra stuff, specifically when you have to update the system: desktop applications have frecuently security updates, as other applications, but I’m not using them in a server so I feel it’s a waste of time and bandwith.

I tend to say base system as synonymous for bare minium install, and yesterday I had a little problem with a partner and a CentOS install.

We requested just base and the IT guy did a default install, that includes all the Gnome desktop and associated applications. That’s not a big deal, but it’s not the optimal situation.

What do you think? Are you OK with a desktop installed in a server?

by jjm on 7:32am  |   URL: http://tmblr.co/ZPorZy7nlcJ
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Filed under: CentOS base install CLI console Server Desktop 
May 27, 2009
Release of the CentOS Directory Server

I’m a OpenLDAP guy, but some time ago I had to use Fedora Directory Server to test the LDAP interoperatibility of a product. I only played with it on the surface, but seems to have a nice set of features.

It’s good news that CentOS users can enjoy this directory server as alternative to OpenLDAP.

by jjm on 9:08am  |   URL: http://tmblr.co/ZPorZy6nfXE
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Filed under: CentOS FDS CDS LDAP Red Hat 
April 1, 2009
Release for CentOS-5.3 i386 and x86_64

You can check the release notes.

CentOS is an Enterprise-class Linux Distribution derived from sources freely provided to the public by Red Hat. CentOS conforms fully with Red Hat redistribution policy (mainly they change the packages to remove Red Hat branding and artwork), and aims to be 100% binary compatible.

So CentOS is a nice choice if you want to play with a Red Hat without paying support.

by jjm on 8:22am  |   URL: http://tmblr.co/ZPorZy5UKJK
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Filed under: CentOS RHEL 5.3 
December 9, 2008
Spacewalk

Spacewalk is an Open Source solution for Linux systems management. It’s the community project for Red Hat Network Satellite, since June 2008.

You can do inventory of your systems (hardware and software), install and update software, create custom distribution groups, provide new systems installation with kickstart, manage and deploy configurations, monitor systems, etc.

I’ve not tested it, but after reading its features seems a killer application if you have to manage a vast number of systems and you don’t want to go crazy. I wish I have time to try it.

In case you don’t mind to work with Fedora and/or CentOS. Thanks you Red Hat!

by jjm on 7:58pm  |   URL: http://tmblr.co/ZPorZy3pyKA
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Filed under: red hat centos fedora sysadm spacewalk 
December 4, 2008
Starting To Appreciate YUM

After being an old FreeBSD/OpenBSD user and Debian (now Ubuntu) lover, using yum it’s a pain in the ass (oh, aptitude, apt-get and co; I love you… and I miss you all).

Today I had to install some packages in an OpenSuse 10. After using YaST for a while… OK, I admit YUM is not as bad as it seems.

Anyway, a package manager is not something to worry about in a Linux distro because you’re most of the time doing real stuff rather than installing software. It’s a pity that my work actually it’s installing software.

by jjm on 5:12pm  |   URL: http://tmblr.co/ZPorZy3mPzf
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Filed under: CentOS YUM OpenSUSE YaST