CentOS is a Linux distribution standing for "Community ENTerprise Operating System" and is a rebuild of "Red Hat Enterprise Linux" (RHEL). The "CentOS6" tag refers to versions 6.x of CentOS.

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7answers
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How to create a symbolic link without using ln?

I deleted a critical symbolic link - libc.so.6. I have the file it should point at, but the basic commands such as ln or wget won't work anymore due to the link missing. However, echo or other Bash ...
24
votes
2answers
57k views

How do I configure LDAP on Centos 6 for user authentication in the most secure and correct way?

During the last couple of days I have been using a lot of F-words, while browsing Internet for good documentation about how to setup an LDAP-server. So far I have found none, but plenty that are less ...
15
votes
3answers
27k views

How do I upgrade to the latest PHP version in CentOS with yum?

I found some blog posts about this, but it's rather lack of descriptions on possible side effects. I could really use some detailed on these steps: How to add a repo that provides PHP 5.4 into yum ...
14
votes
2answers
2k views

HP DL380p Gen8 (p420i controller) I/O oddity on XFS partitions

On DL380p gen8 servers using XFS on top of LVM on top of raid 1+0 with 6 disks, an identical workload results in a ten-fold increase in disk writes on RHEL 6 compared to RHEL 5, making applications ...
13
votes
2answers
11k views

CentOS 6 and upstart

The new CentOS 6 comes with Upstart, replacing init. I am trying to convert an /etc/inittab file to the new upstart format. This particular server only has 15 or so inittab entries, however, other ...
13
votes
2answers
11k views

What does that mean: packages excluded due to repository priority protections

When updating with yum i recieve the following message: yum update Loaded plugins: fastestmirror, priorities Loading mirror speeds from cached hostfile * atomic: www7.atomicorp.com * base: ...
13
votes
2answers
27k views

Upgrade CentOS 5.x to CentOS 6.x - tips and techniques

Now that CentOS 6.0 is making its way to the various mirror sites, I wanted to solicit opinions on the upgrade process. In working with the commercial RedHat 5.6 and 6.x distributions for the past few ...
12
votes
1answer
5k views

What is the correct way of getting crontab on CentOS 6?

I have a server running CentOS 6.2 minimal, but it doesn't appear to have crontab installed by default? crontab -e -bash: crontab: command not found In searching google, I found references to a ...
11
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4answers
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How do I change timezone in centos 6.2?

Here is the output of my date command: [root@r1304 ~]# date Wed Apr 18 15:43:28 GST 2012 I want to change the default system timezone to Asia/Dubai. I've fallowed a tutorial and did fallowing: ln ...
9
votes
3answers
8k views

Virtualbox centos no eth0

just installed a fresh centos-minimal and i can not get bridged network to work or any of the networks not even in host-only mode. when you run ifconfig there is no eth0 only a lo, also when you cat ...
9
votes
6answers
15k views

CentOS 6 and locale error

I just installed CentOS 6 and whenever I login to the system via SSH remotely, I get the following error: -bash: warning: setlocale: LC_CTYPE: cannot change locale (UTF-8) When I type "locale" on ...
9
votes
4answers
2k views

How to use kdump/crash to investigate an OOM issue?

The problem A server crashed after multiple "Out of memory" messages and I am trying to pinpoint the culprit. If it is in userland - which process. If it is in the kernel - which kernel module. ...
9
votes
3answers
376 views

IPA dynamic DNS updates only the AAAA record. Where are my A records?

I'm setting up a FreeIPA domain. In my lab are three virtual machines: the domain controller ipadc1, and two clients puppet and wordpress (creative, yes, I know). All three VMs are running freshly ...
9
votes
2answers
1k views

How to check CentOS 6 Server VM Host after a power falure?

This afternoon, someone at our office decided to pull the plug out of our server because it was storming outside. They didn't shut it down, they just pulled the plug out while it was running. The ...
8
votes
1answer
735 views

Is installing a GUI on my CentOS server a good idea?

I have a new dedicated server that I'm going to create a couple of VMs on. OS will be CentOS 6.5, for the host and the VMs. Does the GUI on the host (Gnome etc) give any real benefit when it comes ...
8
votes
2answers
550 views

Network traffic doesn't appear to leave the trunk

I'm in the process of staging up some new virtualization servers, and part of that is to get some higher-bandwidth pipes into them. The ultimate goal is to bind 4 GigE ports into a single trunk ...
7
votes
2answers
2k views

Persist IP address alias across reboots in CentOS/RHEL 6 using “ip” command

I've always used the ifcfg-eth0:1 alias files to create additional addresses. However, in recent rhel documentation, it states that: As the ip command of the iproute package now supports assigning ...
6
votes
2answers
9k views

What is the correct way to load modules for iptables on Centos 6

Where should I load iptables modules, for example ip_conntrack and ip_conntrack_ftp. Places I have found that might be candidates, but are they? The IPTABLES_MODULES variable in ...
6
votes
3answers
8k views

OOM killer killing things with plenty(?) of free RAM

The OOM killer seems to be killing things despite having more than enough free RAM on my system: (Full resolution) (Full resolution) 27 minutes and 408 processes later, the system started ...
6
votes
3answers
5k views

CentOS 6 Minimal or Hardened Install

I am working on building some new CentOs 6 servers and creating documentation for the installation of said servers. I would like to create a base CentOS 6 server install that would be light on the ...
6
votes
2answers
7k views

ipmitool - can't find /dev/ipmi0 or /dev/ipmidev/0

Based on a previous question, I installed ipmitool (yum install ipmitool). Even after a reboot, though, i get the following error when trying to run ipmitool power status: Could not open device at ...
6
votes
1answer
4k views

How do I view the contents of a SELinux policy package

As the title says, how do I view the contents of a SELinux policy package? The resulting files end with .pp. I'm running on centos 6, but I guess it's the same way on "all" distros. For example ...
6
votes
2answers
897 views

SVN Checkout error on large repositories

I wonder if anyone can help me. We have recently migrated our Subversion repository from a VisualSVN Server on Windows to a subversion server on CentOS. The migration was succesfull however we are ...
5
votes
6answers
2k views

./kernelupdates 100% cpu usage

I have a CENTOS6 server running with some wordpress & tomcat websites. In the last two days it has been crashing continuously. After investigation we found that kernelupdates binary consuming 100% ...
5
votes
3answers
2k views

gpg --gen-key hangs at gaining enough entropy on centos 6

Trying to generate a key for a server. gpg --gen-key We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize ...
5
votes
4answers
10k views

Munin on Centos 6 - missing perl MODULE_COMPAT_5.8.8

I'm trying to install Munin on a new VPS through yum install munin but I keep getting an error about a missing perl module: Requires: perl(:MODULE_COMPAT_5.8.8). This is the perl version currently ...
5
votes
2answers
6k views

CentOS /usr/local/lib system wide $LD_LIBRARY_PATH?

I install custom software in /usr/local/lib. How do I set the PATH and LD_LIBRARY_PATH in CentOS 6 system-wide to use /usr/local/lib. I realize there may be more than one way. What's the simplest and ...
5
votes
1answer
904 views

CentOS is ignoring my public key

I am trying to connect to my own CentOS server using SSH; I am able to connect fine with a password; I am trying to connect with my public key, but the server does not attempt public key ...
5
votes
3answers
2k views

CentOS6 installation from CentOS5 box?

I am trying to build a new CentOS 6 VM from my CentOS 5 host, but it appears that something fundamental has changed between these versions: $ rpm -ivh --nodeps --nodigest --ignorearch --ignoreos ...
5
votes
1answer
273 views

linux OOM-kill why?

. Greetings, fellow admins. I post in the hope of shedding light on the OOM-kills that haunt one of my company's machines. I cannot decide if they are legit OOMs or not. It's a Centos 6.x with kernel ...
5
votes
2answers
1k views

Modify XFS filesystem creation parameters during kickstart installation

I'm streamlining the kickstart process for a series of EL6.2 (RHEL, CentOS, SL, etc.) systems. I'd prefer to use XFS over ext4 for the growth/data partition. However, I'd like some control over the ...
5
votes
2answers
474 views

yum update entire release but limit to a prior version

We need to update yum update but we want to stay one release back. For example, we have CentOS 6.2 and want to move to 6.3. By default, it looks like yum update will install 6.4. On RedHat, this ...
5
votes
3answers
1k views

Where is the correct place to set net.netfilter.nf_conntrack_buckets?

I'm currently trying to set net.netfilter.nf_conntrack_buckets on boot. I initially assumed that this could be done through sysctl.conf, but net.netfilter.nf_conntrack_buckets (and other ...
5
votes
1answer
518 views

Block outgoing connections for certaing uids (root, apache, nobody)

With iptables in CentOS 5 and 6 Linux - how can you please prevent processes running as root, apache or nobody from initiating outgoing connections? On CentOS 5 Linux I've tried putting these lines ...
5
votes
3answers
4k views

Interpreting cryptic kernel “page allocation failure” messages

I have a multi-user CentOS 6.1 database system running an application named ABC. The server is 64-bit, 8GB RAM and 6 vCPU (on VMWare ESXi 4). We get frequent dumps into the dmesg and the system logs ...
5
votes
3answers
9k views

Howto install php 5.2.17 on centos 6 x86_64

Does anyone know how to install php 5.2.17 on a 64bit centos 6 install? I've got a old legacy system that requires php 5.2.17, but centos 6 only supports php 5.3. I've installed repo's such as ...
5
votes
2answers
423 views

Why would Linux VM in vSphere ESXi 5.5 show dramatically increased disk i/o latency?

I'm stumped and I hope someone else will recognize the symptoms of this problem. Hardware: new Dell T110 II, dual-core Pentium G850 2.9 GHz, onboard SATA controller, one new 500 GB 7200 RPM cabled ...
5
votes
2answers
2k views

Filesystem passthrough functionality in Centos 6.2?

I have a CentOS 6.3 machine currently running 2 virtualized CentOS 6.2 machines via KVM/QEMU/Libvirt. I'm trying to setup filesystem passthrough between the guests and the host. However the option is ...
5
votes
3answers
1k views

Broadcom BCM5716 Hangs on CentOS 6 Boot

I have a fresh CentOS 6 installation on a Dell R310 server with a Broadcom BCM5716. The onboard NIC is causing the boot to hang for some reason. Welcome to CentOS Linux Starting udev: udev: starting ...
4
votes
3answers
545 views

Update from zfs-0.6.2-1.el6.x86_64 to zfs-0.6.3-1.el6.x86_64 has made by zpool unreadable

After running # yum update zfs and restarting my CentOS 6 ZFS on Linux system can no longer see or interact with it's zpools. # zpool status no pools available # zpool import zpool: ...
4
votes
3answers
7k views

ls hangs for a certain directory

There is a particular directory (/var/www), that when I run ls (with or without some options), the command hangs and never completes. There is only about 10-15 files and directories in /var/www. ...
4
votes
2answers
6k views

How do I get openldap on Centos 6 to write anything to it's log files

I don't get any information in my log file for openldap on my Centos 6 server. This is how i configured it. SELinux is disabled at the moment. First created a folder where I'd like to store the log ...
4
votes
1answer
341 views

Why do I get different openssl versions?

I'm trying to check if I running the latest OpenSSL version, my main concern is the heartbleed bug. I tried 2 commands: openssl version yum info openssl openssl version output OpenSSL ...
4
votes
4answers
1k views

No outbound internet connection after restarting CentOS 6.3

After restarting a headless CentOS 6.3 machine, it lost outbound internet connectivity, i.e. I can still connect to the server via SSH (ssh root@**.126.18.56), but stuff such as ping google.com gives ...
4
votes
2answers
305 views

How to pass input from one script into another using bash

I am writing a script where I am want to launch the mysql_secure_installation script and provide the appropriate answers at each prompt. I tried using echo like this: echo -e ...
4
votes
2answers
488 views

Forwarding 80 to 443 on Nagios woes

I perhaps just need some extra insight because I don't see where I'm going wrong. I used an SSL Cert to secure our nagios server. We want to specifically require all traffic over nagios (like 2 users, ...
4
votes
3answers
3k views

CentOS disable filesystem check: superblock last mount time is in the future

I'm persistently getting the "Superblock last mount time is in the future" error when booting CentOS 6. I've seen other questions which ask how to resolve this error, but I know exactly why it's ...
4
votes
2answers
5k views

CentOS install proftpd with yum

Server: CentOS 6.2 64bit How can I install Proftpd using yum? A search for the package doesn't find it: yum list proftpd Error: No matching Packages to list Although my CentOS 6 VPS does find it, ...
4
votes
1answer
500 views

Should these log errors worry me?

So I don't get whats with all these error messages. I was told someone may be attempting to hack my server, but I ain't 100% sure whats going on. I am running CentOs 6. Here is a list of errors that ...
4
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1answer
1k views

Starfield Wildcard SSL Certificate Not Trusted in All Browsers

I am at a loss as to what else I might try in order to debug this issue with a Starfield Wildcard SSL Certificate. The problem is that in certain browsers (Safari or the most-updated chrome you can ...