blas.phemo.usTres' Notes from Under*nix |
Posted by Tres Mon, 03 Nov 2008 09:34:00 GMT
Installing the mysql Gem under RHEL/CentOS requires you to specify where MySQL is installed. Just point Gem to the mysql-config bin & you’re good to go:
gem install mysql -- --with-mysql-config=/usr/bin/mysql_config
Posted by Tres Thu, 14 Feb 2008 06:03:00 GMT
Every once in a while, I need to say my old mantra, “it’s always the little things.” The biggest of problems always seem to boil down to the littlest of problems in the world of *nix. Here’s another example.
If you’ve upgraded your version of Xen on CentOS/Red Hat Enterprise Linux from the included Xen 3.0.x to the latest available from XenSource (3.2 at this time), you may run into something like this in /var/log/xen/xend.log when trying to start xend:
INFO (SrvDaemon: ) Xend Daemon started INFO (SrvDaemon: ) Xend changeset: unavailable. INFO (SrvDaemon: ) Xend version: Unknown. ERROR (SrvDaemon: ) Exception starting xend ((13, 'Permission denied')) ... Error: (13, 'Permission denied')
and something like this in /var/log/xen/xend-debug.log
sysctl operation failed -- need to rebuild the user-space tool set? Exception starting xend: (13, 'Permission denied')
The error in the debug log is misleading. I spent my time looking for duplicate installs of xen tools that may have been installed. My theory was that the Red Hat supplied Xen RPM installed files that the XenSource SRPM spec file puts in a different spot, or some other bookkeeping issue related to rpm -Uvh on the xen RPM files.
It turns out I was right, but was looking at the wrong source of the issue. The Xen tools were indeed mismatched, but it was to the running kernel. The xen RPM installed the tools and the kernel and did everything it was supposed to, but it didn’t update grub.conf to boot with the updated xen kernel files that were installed.
“It’s always the little things.” It’s often embarrassing, and this is no exception, but I thought I’d put this out there so if someone else gets caught looking at the wrong source of a mismatched user-space tool set error, they can avoid the trouble of looking for rogue tool installations and get on with business. Just update your /boot/grub/grub.conf with something like the following (<DANGER, WILL ROBINSON>:needless to say, copying and pasting grub.conf entries without verifying them can land you in a heap of trouble if you don’t have local access to your server</DANGER, WILL ROBINSON>):
title CentOS (xen-3.2)
root (hd0,0)
kernel /xen.gz ro root=/dev/vol00/root dom0_mem=256M
module /vmlinuz-2.6.18-53.1.13.el5xen ro root=/dev/vol00/root
module /initrd-2.6.18-53.1.13.el5xen.img
<DANGER>:This entry is very much dated, and uses the latest CentOS 5.x kernel as of this writing</DANGER>. The thing that won’t change, and will continue to be valid no matter what version of Xen you build and install later, is the kernel line:
kernel /xen.gz
The XenSource RPM & SRPM will build things so that /boot/xen.gz is a symlink to the latest version installed.
Posted by Tres Thu, 20 Dec 2007 15:05:00 GMT
The Hyperic documentation says you should just need to install xorg-x11-libs and libXp to get Hyperic server running on CentOS5. That’s not quite true. In order to get things running I also needed to install xorg-x11-utils.
Posted by Tres Sat, 14 Apr 2007 12:31:00 GMT
The plus repositories allow access to hundreds of additional packages that aren’t shipped with RedHat Enterprise Linux. These are packages that are tested by the CentOS team and are considered to extend the functionality of RedHat distributed packages.
You can temporarily enable the CentOS plus repository by using the –enablerepo flag.
yum --enablerepo=centosplus install PackageName
You can permanently enable the centosplus repository by editing /etc/yum.repos.d/CentOS-Base.repo and changing the [centosplus] directive from enabled=0 to enabled=1
[centosplus] name=CentOS-$releasever - Plus mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus #baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/ gpgcheck=1 enabled=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
Posted by Tres Sat, 13 Jan 2007 04:18:00 GMT
Don’t ask me why, but yum isn’t enabled by default on the OpenVZ distributed centos-4 template. Luckily, getting it running is just a matter of installing a few RPMS. Paste the next few lines into a console in your CentOS 4 VE
rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/rpm-python-4.3.3-18_nonptl.i386.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/python-urlgrabber-2.9.8-2.noarch.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/libxml2-python-2.6.16-6.i386.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/python-elementtree-1.2.6-4.2.1.i386.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/sqlite-3.3.3-1.2.i386.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/python-sqlite-1.1.7-1.2.i386.rpm rpm -ivh http://mirrors.kernel.org/centos/4.4/os/i386/CentOS/RPMS/yum-2.4.3-1.c4.noarch.rpm
Posted by Tres Sat, 13 Jan 2007 00:02:00 GMT
Using yum simplifies package management under Red Hat systems. The problem is that by default, Red Hat only provides a relatively small subset of applications available for *nix systems. Adding new package repositories allows access to thousands of applications that you might otherwise have to compile and manage yourself.
In order to set up new repositories in yum, you’ve got to do two things:
1) Import the GPG key for the repository
2) Add the repository information to a file in /etc/yum.repos.d/
UPDATE Dries repos currently only work with RHEL 3/CentOS 3 and RHEL 4.
rpm --import http://dries.ulyssis.org/rpm/RPM-GPG-KEY.dries.txt wget -P/etc/yum.repos.d/ http://blas.phemo.us/files/dries.repo
rpm --import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt wget -P/etc/yum.repos.d/ http://blas.phemo.us/files/dag.repo
rpm --import http://www.jpackage.org/jpackage.asc wget -P/etc/yum.repos.d/ http://blas.phemo.us/files/jpackage.repo
The jpackage.repo file is configured for use with RHEL/CentOS systems. You can also download the Jpackage provided repo file at jpackage.org. You’ll just have to edit it to enable for your platform.
rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ wget -P/etc/yum.repos.d/ http://blas.phemo.us/files/openvz.repo