Red Hat Enterprise Linux version 6 is a Linux distribution sold by Red Hat, Inc. for the enterprise market. It is used for both servers and desktops. Although the binaries are not freely available, the sources are, and so there are numerous projects which provide compatible rebuilds of RHEL, such as ...

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74
votes
2answers
34k views

IPTABLES - Limit rate of a specific incoming IP

I do not wish to limit the rate of a specific service. My goals is to limit rate based solely on the incoming IP address. For example using a pseudo-rule: john.domain.local (192.168.1.100) can only ...
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
28k 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 ...
11
votes
2answers
6k views

Anything Close to an NSA Guide for Securing RHEL 6

Some in our infrastructure group want to upgrade to start taking advantage of the new features in RHEL 6. In the past, I have relied on the NSA Guide ...
10
votes
2answers
2k views

Do I need a RHEL subscription to install packages?

I'm new to RHEL. Trying to install software this morning and running into road blocks. Is it required to have a subscription to download packages via yum on RHEL? I'm coming across different sources ...
10
votes
3answers
681 views

RedHat: is it possible to install packages in a kind of mock environment to build RPMs

Is there a tool that allows to install the dependecies of an RPM .spec into an isolated environment? I won't install such dependencies globally on the system and I am not able to do so since I have ...
9
votes
3answers
5k views

RHEL 6.4: Mode 1 channel bonding not failing over

I'm running RHEL 6.4, kernel-2.6.32-358.el6.i686, on an HP ML 350 G5 with two onboard Broadcom NetXtreme II BCM5708 1000Base-T NICs. My goal is to channel bond the two interfaces into a mode=1 ...
9
votes
2answers
3k 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 ...
7
votes
1answer
1k views

How do I make a persistent domain with virsh?

virsh create somefile.xml creates my machine just fine but when I shut the machine down the whole thing disappears. Machines I made with the virt-manager GUI are persistent (stick around after ...
7
votes
2answers
2k views

What in a kickstart file sets the desktop GUI as default (runlevel 5)?

I am using Scientific Linux 6 and am installing the following desktop-related package groups: @basic-desktop @desktop-platform @general-desktop @x11 However, after installation, /etc/inittab still ...
7
votes
1answer
501 views

How can I use SELinux to confine PHP scripts?

I want to compartmentalize different PHP applications on my SL6.4 (RHEL 6.4 rebuild) web server so that they cannot access each others' data. It seems that SELinux might be able to do this, but I am ...
6
votes
1answer
128 views

RHEL6 Keeping 1 old kernel and security

I have my RHEL 5&6 servers set to keep 1 old kernel after updates, I do this in case I need to recover the system for any number of reasons. My question is related to security of the system when ...
6
votes
1answer
3k views

“power limit notification” clobbering on 12G Dell servers with RHEL6

Server: Poweredge r620 OS: RHEL 6.4 Kernel: 2.6.32-358.18.1.el6.x86_64 I'm experiencing application alarms in my production environment. Critical CPU hungry processes are being starved of resources ...
6
votes
3answers
618 views

How to make NTP work despite a high offset?

Recently I have kickstarted some servers that had their time off by a month in the bios. The time in the bios said it was a random time/date in May, while it was June. This caused NTP not to work, ...
6
votes
2answers
2k views

Php pdo_dblib - cannot find/unable to load freetds

Self-hosted box, RHEL 6 PHP 5.3.3 PDO installed freetds installed pdo_dblib - so far no luck installing My goal is to use PDO with sybase. Attempting to install pdo_dblib from the appropriate ...
5
votes
3answers
2k views

How to free up space on RHEL6 /boot safely?

I am trying to do yum update on RHEL 6 box and I am getting this error message Transaction Check Error: installing package kernel-2.6.32-279.9.1.el6.x86_64 needs 10MB on the /boot filesystem ...
5
votes
2answers
520 views

What is the yum equivalent of dpkg -L?

dpkg -L lists all the files provided by a package. How is this accomplished with yum? The operating system is Scientific Linux 6.
5
votes
2answers
425 views

Anaconda kickstart and rootpw option

I've tried a few different methods of generating an encrypted password on SL 6.5, but nothing seems to work for me. I'm not finding any errors anywhere in the various /var/log/anaconda* files, but I ...
5
votes
2answers
2k views

How to kill ostensibly immortal process?

I had some huge file transfers operating on an NFS mount. The server on which the mount point resided was carelessly rebooted, and now the server from which these large transfers were initiated seems ...
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
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
4k views

How come all LDAP users are shown with getent passwd?

We are using an LDAP server with both Solaris and RHEL servers and planning to migrate more servers over to RHEL. However we have an issue with LDAP on all Red Hat servers. When I type "getent ...
5
votes
2answers
8k views

Account Lockout with pam_tally2 in RHEL6

I am using pam_tally2 to lockout accounts after 3 failed logins per policy, however, the connecting user does not receive the error indicating pam_tally2's action. (Via SSH.) I expect to see on the ...
5
votes
2answers
733 views

apache/httpd responds slower under EL6.1 than EL5.6 (CentOS)

I've read through other threads on performance differences between RHEL 6 and RHEL 5, but none seem a tight match to mine. My issue manifests itself in slightly slower average response time (20ms) ...
4
votes
3answers
3k views

Understanding RedHat's recommended tuned profiles

We are going to roll out tuned (and numad) on ~1000 servers, the majority of them being VMware servers either on NetApp or 3Par storage. According to RedHats documentation we should choose the ...
4
votes
5answers
2k views

Reboot fails on RHEL 6.1 after kernel update on Amazon EC2

Everytime I start a new RHEL instance, I like to perform a yum update to start with the most up-to-date system. However, everytime I try to reboot the instance after that, the instance never goes ...
4
votes
5answers
656 views

Degraded httpd performance after moving from RHEL 5.6 to 6.1

We have recently replaced an RHEL 5.6 web server with RHEL 6.1. For both environments, the (stock) Redhat shipped Apache httpd has been used (i.e. yum install httpd). The server is serving PHP ...
4
votes
3answers
6k views

What is the relation between NetworkManager and network service in Fedora/RHEL/Centos?

Hi I am new to Fedora/Centos/RHEL. I am confused about NetworkManager and network service in these Linux OS. May I know what is the relation between NetworkManager and network service? If I am using ...
4
votes
2answers
3k views

SL6: Non-standard home directories, Error: `Could not chdir to home directory` upon login, but `cd $HOME` works?

I have a brand new Scientific Linux 6 instance (Similar to RHEL6 & CentOS6), running on Parallels. The home directory is in a non-standard location, which I'll call /homedir When I ssh into this ...
4
votes
2answers
685 views

Dangers to giving Apache user a shell

tl;dr - What are the dangers of giving Apache a shell in /etc/passwd? I'm working on getting mod_evasive set up with Apache to fight DOS attempts. I use the DOSSystemCommand to run a script that ...
4
votes
4answers
2k views

PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/gd.so' undefined symbol: gdImageWebpCtx in Unknown

We're running RHEL6 and just started getting this error when restarting php-fpm. PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/gd.so' - /usr/lib64/php/modules/gd.so: ...
4
votes
1answer
124 views

How to prevent installation of incompatible rpm packages

I have two rpm packages wich should not get installed together. After googling around i assume there is no RequiresNot tag or something similar to specify incompatible packages in a specfile. What ...
4
votes
2answers
9k views

How can I install git on RHEL 6?

I'm trying to install Git on a RHEL6 development server, I have experience with Ubuntu but this is my first time working with RHEL (I'm a developer trying to fill in for a recently departed Linux ...
4
votes
2answers
472 views

packets sent on virtual IP don't hit iptables rule

I have a virtual interface eth1:3 with IP address 222.192.124.3, I have set up an iptables rule to log packets coming on that interface using the interface's IP (I know iptables doesn't care about ...
4
votes
1answer
412 views

How can I force sudo to accept a user's AD password on RHEL6

In our environment we do not join Linux boxes to the Microsoft Domain. We do however setup Kerberos. This allows us to log into the boxes using our AD credentials as long as there is a local account ...
4
votes
1answer
288 views

RHEL/CENTOS6 Interface naming and IP assignment for rotating MACs

Background: I am creating an RHEL6 OS disk image that will potentially be passed around to many different computers with identical hardware (except for serial numbers such as MACs). The image is ...
4
votes
1answer
3k views

Why is my RHEL6 x86_64 server trying to install libselinux.i686?

Just did a fresh install using the RHEL 6 DVD on a test VirtualBox server: [root@bt-rhel6-1 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.1 (Santiago) I am certain it's an ...
4
votes
1answer
779 views

chkconfig creating service symlinks with the wrong order

On RHEL 6.3, I have a system service that should be starting after postgresql and httpd (order 64 and 85, respectively), but chkconfig always places it at order 50. I tried an experiment on a CentOS ...
4
votes
1answer
210 views

AD GIT SELinux RHEL 6 : Can not get SELinux to allow connetion to git

I have a problem with SELinux! I have installed git on Red Hat Enterprise 6 with AD group control and SSL Cert . Everything works fine if I do setenforce 0 ( set SELinux in detection only mode ) or ...
4
votes
1answer
2k views

Are Link-Local routes necessary (IPv4)?

I noticed in my routes output in RHEL6 (and most 2.6.x series Linux), for every interface I see the creation of the following route in my kernel routing table: 169.254.0.0 0.0.0.0 ...
3
votes
4answers
10k views

Can I set up Fedora or Centos repos in RHEL6?

I have a RHEL6 box with no subscription to Red Hat Network. I want to install gcc using yum to resolve all the complex dependencies. Can I connect to Fedora or Centos repositories to install software? ...
3
votes
4answers
15k views

RHEL 6 x64: running 32 bit applications

We develop an application which currently works in 32 bit mode only. It worked fine in RHEL 5 but failed to work in RHEL 6. The reason is RHEL 6 by default is installed with 64 bit libraries only. ...
3
votes
1answer
164 views

Locking user account on RHEL using PAM LDAP

I have a bit of an edge case here. My institution has a RHEL server where students can log in and do their work. Accounts are held in LDAP and the server uses PAM and LDAP to authenticate. At the end ...
3
votes
2answers
5k views

Clone kvm/qemu VM to a different server

What's the easiest/quickest way to clone a VM from one server onto another if you don't have shared storage between the two servers (so you can't do a standard migration)? I have a production ready ...
3
votes
2answers
3k views

KVM on RHEL 6.1 makes host sluggish

I have been running RHEL 5.7 on a host just fine with several VMs (KVM). No major issues. Time came to upgrade to RHEL 6.1 as a few bugs had been fixed in this release. When I start a VM or two under ...
3
votes
1answer
61 views

RHEL6 httpd Root CA configuration

I'm setting up SSL on a RHEL6 box and I'm having problems finding information about configuring the Root CAs. I've got four files: cert.crt - My SSL certificate my_key.key - The key used to ...
3
votes
1answer
562 views

How to detect if mount point exists from init.d script?

After a reboot, I'm executing an application from a mounted network share (autofs) using an init.d script. The script starts by waiting 30 seconds before attempting to execute the command, in order to ...
3
votes
4answers
1k views

Reloading a kernel “live” in CentOS / RHEL 6

When upgrading the kernel package on CentOS or RHEL 6, is it possible to load the new kernel without rebooting? My gut tells me it's not, but if it were, it'd be handy - especially when compiling ...
3
votes
1answer
2k views

What are the disadvantages of disabling tinker panic 0 in NTP?

We sometimes have the problem that new servers have the wrong time in the bios, so there time can be off by a month. When you suspend a VM in VMware and then unsuspend it, the time will be off too. ...
3
votes
1answer
381 views

Why is ATLAS not detected on RHEL when I try a SciPy installation through pip?

I'm using RHEL6, Python 2.6.6, and trying to install SciPy through pip. [user@server ~]$ sudo pip install scipy <snip> atlas_blas_threads_info: Setting PTATLAS=ATLAS libraries ...