Chris Schuld’s Blog

A while back I wrote an article on updating to ghostscript 8.63 on CentOS 5.2. I received a fair amount of email and comments on the topic ranging from “thanks” to “you don’t know what your talking about!” I thought I would update the original post to include the latest release of ghostscript (8.7) as well as answer and respond to the best question / statement in the comments… “how do you do that and can you post the SRPMS?” The answer is, yes, here is how I do it and “yes” I’ll post the SRPMs (or more appropriately where I get them).

First, you have to have the latest version of the build environment as well as some prerequisites for building GhostScript:

yum --enablerepo remi groupinstall "Development Tools"
yum --enablerepo remi install libjpeg-devel libXt-devel libpng-devel gtk2-devel glib2-devel gnutls-devel libxml2-devel libtiff-devel cups-devel libtool jasper-devel

(you will note here I use the REMI repo)

Next, I obtain the SRPM files from rpmfind.net and ghostscript-fonts from the centos repo:

wget ftp://195.220.108.108/linux/fedora/development/source/SRPMS/ghostscript-8.70-3.fc13.src.rpm
 
wget http://mirror.centos.org/centos/5.4/os/SRPMS/ghostscript-fonts-5.50-13.1.1.src.rpm

Now, I build them using RPM (rpmbuild):

rpmbuild --rebuild ghostscript-8.70-3.fc13.src.rpm
rpmbuild --rebuild ghostscript-8.70-1.fc10.src.rpm

… and that is how I do it! If you are feeling exceptionally lazy and have some inherent trust for my builds in x86_64… here they are:

rpm -Uvh http://chrisschuld.com/centos54/ghostscript-8.70-1.x86_64.rpm http://chrisschuld.com/centos54/ghostscript-fonts-5.50-13.1.1.noarch.rpm http://chrisschuld.com/centos54/ghostscript-gtk-8.70-1.x86_64.rpm

Disk space can be easily controlled via OpenVZ but I have yet to find anyone to actually explain what the heck to “really” do when you need to add more! Everything I have found about OpenVZ just explains the parameters and never shows you how to do it easily. When I need to adjust disk space on an VPS it is usually when I have someone beating up my ear on the phone or my IM so I needed a fast way to expand the disk without worrying about the details.

There are three parameters in OpenVZ which are directly related to disk usage. They are disk_quota, diskspace and diskinodes. NOTE: there are a lot of other parameters that control and effect the disk but this tutorial will only cover the basics!

The parameter disk_quota is a YES or NO value which disables the file system quotas; if you are not worried about the quotas set it to NO and stop reading. Otherwise; leave it set at YES and continue.

The parameter diskspace is the count of 1K blocks available to the VPS in a soft and hard limit. The hard limit is a stop point similar to filling up a physical disk – when you are out, you are out. The soft limit is when the bean counters get angry and the quotatime timer starts. On a basic installation and VPS setup you will have a 1048576 1K blocks as a soft limit and 1153024 1K blocks as a hard limit. The numbers are not crazy as they are derived from base2. Thus, 1048576 1K blocks is 1GB of disk space. Add an additional 10.2MB to the disk space and you arrive at the 1048576 1K blocks. These are the basic numbers for the basic template that ships with OpenVZ.

The parameter diskinodes is the total number of files, directories and links you can have in the container. Think of them as Post-it® notes and each file, directory and link gets a single note. The default basic number is 200,000 for a soft limit for 1GB of disk space and 220,000 for the hard limit. Normally *nix systems will set aside enough inodes for one inode per 4K disk space block. In the default template for OpenVZ they are setting aside enough inodes for 5.2K blocks. Which I’ll write off as either (a) a magic number or (b) a unique calculation I am not familiar with. Thus, because the 4K block inode count for 1GB of disk space should be 262,144 inodes we’ll use the default template values for our calculations and simply multiply times the number of GB requested.

So…

Now…

The question is how do you adjust them quickly and easily. In this example we are going to work with units of GBs. If you need more granularity you will need to divide it back out to MBs but Gigabytes works great for our needs:

First, we need to define the soft and hard limits, next we apply the updated diskspace numbers and finally set the inode numbers correctly based on the ratio we know from the default template:

Here are the commands (and note below for a quick and easy Perl script):

cid=1324
gb=5
vzctl set ${cid} --diskspace $((1048576 * ${gb})):$((1153434 * ${gb})) --save
vzctl set ${cid} --diskinodes $((200000 * ${gb})):$((220000 * ${gb})) --save

#!/usr/bin/perl
 
# display the commands to update an OpenVZ VPS with new disk space requirements
# 2009/11/15 - Chris Schuld (chris@chrisschuld.com)
 
use strict;
 
print "Enter VPS CID: "; my $_CID = <STDIN>; chomp($_CID);
print "Enter SOFT Diskspace Limit (ex 10GB):"; my $_SOFT = <STDIN>; chomp($_SOFT); $_SOFT =~ s/[^0-9]//g;
print "Enter HARD Diskspace Limit (ex 11GB):"; my $_HARD = <STDIN>; chomp($_HARD); $_HARD =~ s/[^0-9]//g;
my $_INODE_SOFT = ( 200000 * $_SOFT );
my $_INODE_HARD = ( 220000 * $_HARD );
print "Run these commands:\n";
print "vzctl set $_CID --diskspace ".$_SOFT."G:".$_HARD."G --save\n";
print "vzctl set $_CID --diskinodes $_INODE_SOFT:$_INODE_HARD --save\n";

There are a few items required for installing vzdump for OpenVZ on CentOS.

First, you’ll need an MTA – I suggest making sure you have postfix installed; if you have postfix installed the initial RPM requirement for “MTA” will be handled for you. Next, you’ll need cstream. This installation is slightly more tricky because (as far as I know) there is no real way to gain this from yum unless you use the DAG Wieers repo. Also, depending on what you have already installed you will likely need the Simple Locking file I/O library for Perl.

Here is how you get vzdump on a clean version of CentOS (via the hostnode):

rpm -ivh "ftp://ftp.pbone.net/mirror/ftp.freshrpms.net/pub/freshrpms/pub/dag/redhat/el5/en/x86_64/RPMS.dag/cstream-2.7.4-3.el5.rf.x86_64.rpm"
wget http://dag.wieers.com/rpm/packages/perl-LockFile-Simple/perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm
rpm -ivh perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm
/bin/rm perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm
rpm -ivh "http://www.proxmox.com/cms_proxmox/cms/upload/vzdump/vzdump-1.2-4.noarch.rpm"

Since version 1.2-4 of vzdump the location of the modules is not “automatic” and have found it necessary to export the location of the PVE libraries that vzdump requires via this command:

export PERL5LIB=/usr/share/perl5/

All said and done there has to be a better way to do this… anyone… anyone??

Here are the commands to install Webmin via Yum:

echo -e "[Webmin]\nname=Webmin Distribution Neutral\nbaseurl=http://download.webmin.com/download/yum\nenabled=1" > /etc/yum.repos.d/webmin.repo
rpm --import http://www.webmin.com/jcameron-key.asc
yum install webmin

All of our servers are currently based off of the Phoenix, Arizona, USA Timezone. This script allows this conversion from each HN (Host Node):

 
#!/bin/bash
for f in `ls /vz/private`
do
  vzctl exec $f rm -f /etc/localtime 2>/dev/null
  vzctl exec $f ln -s /usr/share/zoneinfo/America/Phoenix /etc/localtime
done

Here are commands to help adjust the RAM for an OpenVZ VPS:

64MB Guaranteed, 128MB Burstable

cid=1000
vzctl set ${cid} --vmguarpages $((64 * 64)) --save
vzctl set ${cid} --privvmpages $((64 * 128)) --save

256MB Guaranteed, 512MB Burstable

cid=1000
vzctl set ${cid} --vmguarpages $((256 * 256)) --save
vzctl set ${cid} --privvmpages $((256 * 512)) --save

512MB Guaranteed, 1024MB Burstable

cid=1000
vzctl set ${cid} --vmguarpages $((512 * 512)) --save
vzctl set ${cid} --privvmpages $((512 * 1024)) --save

1024MB Guaranteed, 2048MB Burstable

cid=1000
vzctl set ${cid} --vmguarpages $((1024 * 1024)) --save
vzctl set ${cid} --privvmpages $((1024 * 2048)) --save

I still use a lot of NFS connections on my equipment and when I create OpenVZ VPS systems I need them to have access to NFS. Here are the steps I use:

From the Host Node (HN):

modprobe nfs
vzctl set 101 --features "nfs:on" --save

From the VPS:

yum -y install nfs-utils nfs-utils-lib
chkconfig --levels 345 portmap on
/etc/init.d/portmap start

Here is my quick-and dirty way to build DNS servers using OpenVZ, CentOS and Bind/Named. This assumes you are creating a new server via OpenVZ. Although Bind is easy to admin with the configuration files recently I have found it is easier to simply admin the zones with Webmin. This setup will create the VPS, install Bind and install Webmin.

Create the VPS:

cid=1161
cd /vz/template/cache/
wget http://download.openvz.org/template/precreated/centos-5-x86_64.tar.gz
vzctl create ${cid} --ostemplate centos-5-x86_64 --config vps.basic
vzctl set ${cid} --hostname [HOSTNAMEHERE] --save
vzctl set ${cid} --ipadd [IP] --save
vzctl set ${cid} --nameserver [IP] --save
vzctl start ${cid}
vzctl exec ${cid} passwd
vzctl enter ${cid}

From inside the VPS I install bind and webmin

yum -y install bind bind-chroot bind-libs bind-utils caching-nameserver
cd /root
wget http://prdownloads.sourceforge.net/webadmin/webmin-1.480-1.noarch.rpm
rpm -Uvh webmin-1.480-1.noarch.rpm

Now I simply visit webmin’s panel and tap in any new zones (or copy over our zones from another box).

OpenVZ and virtual serving makes this time-consuming task of bringing new boxes up a simple task!

There are a few tutorials out there on installing OpenVZ in CentOS 5.3. Here are the steps I use to install OpenVZ on a brand new installation of CentOS 5.3:

Note: this tutorial / walkthrough is for use 64 bit only

1. Update the box via yum
2. Install the OpenVZ Repository and grab the GPG key
3. Install OpenVZ
4. Install OpenVZ Controller and Quota system
5. Configure the local system for the OpenVZ kernel
6. Update OpenVZ’s ARP Settings
7. Disable SELINUX
8. Reboot

yum -y update
cd /etc/yum.repos.d
wget http://download.openvz.org/openvz.repo
rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ
yum -y install ovzkernel.x86_64
yum -y install vzctl.x86_64 vzquota.x86_64

Now; we need to configure the sysctl.conf file for OpenVZ

perl -pi -e 's/net\.ipv4\.ip_forward = 0/net\.ipv4\.ip_forward = 1/' /etc/sysctl.conf
perl -pi -e 's/kernel\.sysrq = 0/kernel\.sysrq = 1/' /etc/sysctl.conf
echo -e "\n\nnet.ipv4.conf.default.proxy_arp = 0\nnet.ipv4.conf.all.rp_filter = 1\nnet.ipv4.conf.default.send_redirects = 1\nnet.ipv4.conf.all.send_redirects = 0\nnet.ipv4.icmp_echo_ignore_broadcasts=1\nnet.ipv4.conf.default.forwarding=1\nkernel.ve_allow_kthreads=1\n" >> /etc/sysctl.conf
perl -pi -e 's/NEIGHBOUR_DEVS=detect/NEIGHBOUR_DEVS=all/' /etc/vz/vz.conf

Disable SELINUX

vi /etc/sysconfig/selinux

Reboot the machine

reboot

Here are the steps I continue to use over and over to build utilities/project servers in OpenVZ. Utilities servers host web apps, mailing applications, etc for my company. We usually build them as self-contained little appliance-like servers. My vision and goal is simple == better every day!

First, we create the virtual machine:

cid=1164
cd /vz/template/cache/
wget http://download.openvz.org/template/precreated/centos-5-x86_64.tar.gz
vzctl create ${cid} --ostemplate centos-5-x86_64 --config vps.basic
vzctl set ${cid} --hostname [HOSTNAMEHERE] --save
vzctl set ${cid} --ipadd [IP] --save
vzctl set ${cid} --nameserver [IP] --save
vzctl start ${cid}
vzctl exec ${cid} passwd
vzctl enter ${cid}

Now that we are in the virtual machine and away from the HN we add the REMI repo and apply the updates directly on the box.

wget http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-5.rpm
rpm -Uvh remi-release-5*.rpm epel-release-5*.rpm
/bin/rm epel-release-5-3.noarch.rpm remi-release-5.rpm
 
yum --enablerepo remi -y update
yum --enablerepo remi -y install httpd php php-devel php-pear php-gd php-xsl php-mbstring php-mcrypt php-mysql mysql

Add Postfix and switch it on via system-switch-mail

yum --enablerepo remi -y install postfix system-switch-mail
system-switch-mail

Now… customer configurations and setups…