CentOS is a free (as in beer and speech) GNU/Linux distribution that is community driven and based on source code released from RedHat.

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3
votes
1answer
937 views

Excessive number of sleeping processes in CentOS - howto diagnose? [closed]

I have a a large number of sleeping processes, about 600, the majority of which are Apache processes. Should I kill all these sleeping processes, or will that make Apache fail completely? Why are ...
63
votes
2answers
17k views

Why is it so difficult to upgrade between major versions of Red Hat and CentOS?

"Can we upgrade our existing production EL5 servers to EL6?" A simple-sounding request from two customers with completely different environments prompted my usual best-practices answer of "yes, but ...
37
votes
7answers
31k views

Log all commands run by admins on production servers

It is company policy for admins to login to the servers via a personal username, and then run sudo -i to become root. Upon running sudo -i, sudo will create an environmental variable called SUDO_USER,...
16
votes
7answers
24k views

How can I determine what is taking up so much space? [duplicate]

I was using df -h to print out human readable disk usage. I would like to figure out what is taking up so much space. For instance, is there a way to pipe this command so that it prints out files that ...
30
votes
4answers
98k views

How to configure vsftpd to work with passive mode

Whenever I install vsftpd on centos, I only setup the jail environment for the users and rest is default configuration of vsftpd. I create user and try to connect with filezila ftp client but I could ...
43
votes
1answer
12k views

Why are my XFS filesystems suddenly consuming more space and full of sparse files?

I've run XFS filesystems as data/growth partitions for nearly 10 years across various Linux servers. I've noticed a strange phenomenon with recent CentOS/RHEL servers running version 6.2+. Stable ...
8
votes
3answers
8k views

How to diagnose causes of oom-killer killing processes

I have a small virtual private server running CentOS and www/mail/db, which has recently had a couple of incidents where the web server and ssh became unresponsive. Looking at the logs, I saw that ...
104
votes
17answers
154k views

CentOS vs. Ubuntu [closed]

I had a web server that ran Ubuntu, but the hard drive failed recently and everything was erased. I decided to try CentOS on the machine instead of Ubuntu, since it's based on Red Hat. That ...
50
votes
7answers
41k views

Allow SFTP but disallow SSH?

I'm starting a very little hosting company for a few friends and little clients, nothing big. I want to give my "clients" the right to manage their files on the server. I hate FTP as it is not secure ...
22
votes
12answers
36k views

Disable local delivery in Sendmail

I am using Sendmail on a Centos server to send email for PHP scripts, but the problem is that mail is delivered to a local mailbox on the machine rather than what is specified in the MX records for ...
14
votes
4answers
5k views

Managing an application across multiple servers, or PXE vs cfEngine/Chef/Puppet

We have an application that is running on a few (5 or so and will grow) boxes. The hardware is identical in all the machines, and ideally the software would be as well. I have been managing them by ...
27
votes
12answers
149k views

How to find out details about hardware on the Linux machine?

-i.e - how to get a full list of hardware components in command line (on a machine with no window system) Thank you.
5
votes
4answers
1k views

Recovering from bad chown command

I was going to change the ownership of a directory to apache:apache, but I ended up running: chown -R apache:apache / Bad! Very bad! I knew what was going on when it started saying: chown: ...
32
votes
2answers
80k 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 ...
26
votes
14answers
9k views

Linux IO monitoring per file?

I am interested in a utility or process for monitoring disk IO per file on CentOS. On Win2008, the resmon utility allows this type of drilldown, but none of the Linux utilities I have found do this (...
22
votes
2answers
59k views

Allowing FTP with IPTables

My current scenario involves allowing various rules, but I need ftp to be accessible from anywhere. The OS is Cent 5 and I am using VSFTPD. I can't seem to get the syntax correct. All other rules ...
7
votes
1answer
31k views

Configure Postfix to send/relay emails Gmail (smtp.gmail.com) via port 587

Using Centos 5.4, with Postfix. I can do a mail foo@gmail.com subject: blah test . Cc: and the msg gets sent to gmail, but it resides in the spam folder, which is to be expected. My goal is to ...
9
votes
8answers
33k views

How do I install PHP 5.3 on CentOS?

I have to install PHP 5.3 on my CentOS server. If I do yum install php, the base repository installs 5.1.6 which is too old for the applications I need to install. So I've been trying to use the IUS ...
6
votes
3answers
4k views

How to Tee udp packets onto a different host

I would like to clone incoming UDP packets onto a different host, I found a way to do it Here but I could not build xtables-addons on centos 5.3 . Is there any other way to tee upd packets?
6
votes
3answers
34k views

CentOS 5: How to resolve php53 RPM dependency conflict with php-foo and php-common?

We are running a CentOS 5.6 system, and want to install php53 with php-mcrypt. However, this introduces a dependency conflict between php-common & php53-common. Does anyone have a good workaround ...
3
votes
3answers
3k views

SELinux preventing Apache from writing to a file

SELinux is preventing the apache user from writing to a log file which it owns. When I do setenforce 0 it works. Otherwise it shows this error IOError: [Errno 13] Permission denied: '/var/www/webapp/...
0
votes
1answer
232 views

Two identical files; Apache says one is forbidden

I've got this one file, favicon.ico. It's actually a large group of nested files, but purely for example, just this one. If I do cp favicon.ico favicon2.ico, Apache can read the second one just fine. ...
7
votes
4answers
20k views

How to change Linux services startup/boot order?

As the question is clear from the title, how do I change Linux services startup/boot order?
3
votes
1answer
25k views

CentOS 7 x64 and HP Proliant DL360 G5 SCSI Controller compatibility

I've an HP Proliant DL360 G5 server with two 72gb HDD in RAID and 2 150gb HDD in RAID. I've Windows Server installed on the 72gB HDD and I'm now trying to overwrite it with a fresh installation of ...
2
votes
1answer
3k views

Newer GLIBC for RHEL/CentOS 5.x

I have a situation where a group of developers is attempting to deploy a binary application to a series of RHEL 5.5 and CentOS 5.5 servers. Unfortunately, the application was developed on another ...
3
votes
1answer
647 views

Apache upgrade strategy

I'm on CentOS 6.5 and Apache 2.2.15. I wanted my httpd to be up to date so I did: yum update httpd After that it is still version 2.2.15, but latest version is 2.2.22. I also see security updates ...
3
votes
2answers
2k views

Move /var to new set of disks

I currently only have remote access to this CentOS box, I need to move /var form the primary RAID to a new set of disks that was installed with more space, My current thoughts on how to accomplish ...
2
votes
1answer
807 views

centos: using epel repository on a server machine

Are there any downsides in enabling epel repository on a server machine or is it something every sysadmin does?
118
votes
20answers
116k views

How do you install Node.JS on CentOS?

I've found numerous installation instructions for Node.js but they all seem so complicated -- I'm not a super sys admin but I can get around. I have yum on the system, but I didn't find any node.js ...
82
votes
11answers
18k views

How bad is it really to install Linux on one big partition?

We will be running CentOS 7 on our new server. We have 6 x 300GB drives in raid6 internal to the server. (Storage is largely external in the form of a 40TB raid box.) The internal volume comes to ...
18
votes
4answers
2k views

Monitoring production server [closed]

Hey all, We have 3 dedicated server, splitted in several VPS using openVZ. We're using munin to monitor the VPS with the production sites, and monit on some one of the VPS to make sure it restarts the ...
22
votes
3answers
49k 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 ...
16
votes
2answers
26k views

How do I get SELinux to allow Apache and Samba on the same folder?

In the configuration I have setup I wish to allow samba and apache to access /var/www I am able to set a context to allow samba access, but then httpd doesn't have access. Using setenforce to 0 ...
7
votes
2answers
12k 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 ...
9
votes
2answers
20k views

How to open port for a specific IP address with firewall-cmd on CentOS?

I would like to open port 4567 for the IP address 1.2.3.4 with the firewall-cmd command on a CentOS 7.1 server. How can I achieve this, as the documentation I could find was too specific on this?
9
votes
2answers
3k views

CentOS 6 doing lots more IO than CentOS 5

I'm benchmarking an application on two identical servers, one is Centos 5.8 and the other is Centos 6.2. My application is running much slower (50% or less) on the Centos 6.2 machine. In attempting ...
7
votes
1answer
5k views

CentOS 5 - realtime patch

Where can I download precompiled CentOS 5 kernel including realtime patch? Or I need to compile it myself (if yes, how to do that)?
6
votes
4answers
2k views

Record everything on command line centos /fedora/ ubuntu

we are 100% Linux user across the network and we do work round clock, what happens shift change next admin come to his shift on that time what all issues comes he get resolve the issues but they just ...
8
votes
2answers
23k views

Install libxml2 2.7.X on CentOS 5.X

CentOS ships with libxml2-2.6.26. I have to install at least 2.7.X version. I downloaded RPMs for libxml2, libxml2-devel and libxml2-python (2.7.8) from XMLSOFT (http://xmlsoft.org/sources/). I am ...
7
votes
2answers
11k views

Setting up Exim to forward mail

I'm trying to setup Exim on a fresh CentOS install so that it will receive mail for a collection of given addresses, and forward the mail respectively to another address. For example, receiving mail ...
10
votes
2answers
7k views

HowTo redirect HTTP to HTTPS on the same httpd?

Here is what I have got: CentOS 5.4 (32-bit) installed Apache httpd (Server version: Apache/2.2.11 (Unix)) mod_rewrite already presents Question: how to redirect simple http://site.com to https:...
4
votes
2answers
12k views

How to log on MySQL on CentOS 6.3 using root account from the domain and not localhost?

I don't know if I'll make the issue clear, but I've installed MySQL on CentOS 6.3 using root account on a specific domain (f.ex. root@mydomain), but when I try to log on to it I'm being asked for ...
3
votes
8answers
6k views

MySQL is running VERY slow on CentOS 6x (not 5x)

I have two servers: a VPS and a laptop. I recently re-built both of them, and MySQL is running about 20 times slower on the laptop. Both servers used to run CentOS 5.8 and I think MySQL 5.1, and the ...
8
votes
2answers
1k views

yum-security for CentOS?

Last time I checked I was able to install yum-security in CentOS but since it doesn't use the official redhat mirrors I was unable to get it to actually work. Is there a way to make yum-security work ...
3
votes
5answers
832 views

Is there a way to run kickstart scripts on a pre-existing server?

We normally provision servers using kickstart scripts (served by Cobbler) when installing the operating system. But we are to be given a new server from an ISP that already has the operating system ...
1
vote
1answer
2k views

How do you run Nginx on port 8080 and Apache on port 80 on the same box?

I want to install Node.js on my box (CentOS 5) for testing and sandboxing but I can't uninstall Apache as recommend by developers using Nginx. So what I'd like to do is have Nginx serving nodejs....
0
votes
2answers
711 views

Centos - Automatically issue a command after rebooting

I need to automatically issue a command on my CentOS 4.8 server after it reboots and/or powers up. Can someone please tell me where I can place this? Is there a configuration file somewhere for this? ...
0
votes
1answer
2k views

Hacked CentOS 5 server - possible rootkit installed? [duplicate]

Possible Duplicate: How do I know if my Linux server has been hacked? My server's been hacked EMERGENCY I am running CentOS 5.3 and here is the result of "chkrootkit": Possible t0rn v8 ...
15
votes
9answers
1k views

Resources for beginning Linux administrators

I've just acquired a dedicated linux server which I plan to use to deploy projects and host a few sites from. Unlike virtual or shared hosting services I've used in the past in this case I'm actually ...
26
votes
2answers
72k views

What does “<service_name> dead but subsys locked” mean?

I'm trying to run memcached on a centos box and it runs for a while, but then ends up in this state: memcached dead but subsys locked netstat shows this: tcp 0 0 :::11211 ...