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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97
votes
16answers
84k 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 ...
74
votes
9answers
82k views

When does `cron.daily` run?

When do entries in cron.daily (and .weekly and .hourly) run, and is it configurable? I haven't found a definitive answer to this, and am hoping there is one. I'm running RHEL5 and CentOS 4, but for ...
68
votes
11answers
11k 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 ...
52
votes
2answers
10k 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 ...
46
votes
5answers
37k views

“POSSIBLE BREAK-IN ATTEMPT!” in /var/log/secure — what does this mean?

I've got a CentOS 5.x box running on a VPS platform. My VPS host misinterpreted a support inquiry I had about connectivity and effectively flushed some iptables rules. This resulted in ssh listening ...
38
votes
5answers
20k 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 ...
31
votes
4answers
82k views

Adding a directory to $PATH in CentOS?

We just got our new server(s) up and we're running CentOS on them all. After successfully installing Ruby Enterprise Edition, I would now like to add the REE /bin (located at ...
31
votes
1answer
7k 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 ...
30
votes
2answers
68k 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 ...
27
votes
8answers
3k views

Deploying new code live

What's the best practise to deploy new code on a live (e-commerce) site? For now I have stopped apache for +/- 10 seconds when renaming directory public_html_new to public_html and old to ...
27
votes
3answers
2k views

Is it safe to reboot a server open to the internet?

Specifically I have an iptables ruleset defined on a server running CentOS. Am I guaranteed / can I guarantee / how can I guarantee that when networking comes online (either at machine boot, or after ...
25
votes
13answers
6k 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 ...
25
votes
3answers
10k views

The XFS filesystem is broken in RHEL/CentOS 6.x - What can I do about it?

Recent versions of RHEL/CentOS (EL6) brought some interesting changes to the XFS filesystem I've depended on heavily for over a decade. I spent part of last summer chasing down an XFS sparse file ...
24
votes
8answers
35k views

How do I update a CentOS server's time from an authoritative time server?

I have CentOS machine and each time I've noticed that the server loses correct time after a while. It is usually behind by several minutes after time passes from having manually set the correct time. ...
23
votes
6answers
11k 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 ...
22
votes
12answers
104k 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.
22
votes
4answers
89k views

How do I install an rpm that complains about rpmlib(FileDigests) <= 4.6.0-1?

Im trying to install an rpm file on CentOS 5 and Im not sure how to resolve this issues it brings up: $ rpm --install epel-release-6-5.noarch.rpm warning: epel-release-6-5.noarch.rpm: Header V3 ...
22
votes
5answers
4k views

Unusually high dentry cache usage

Problem A CentOS machine with kernel 2.6.32 and 128 GB physical RAM ran into trouble a few days ago. The responsible system administrator tells me that the PHP-FPM application was not responding to ...
20
votes
4answers
53k 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 ...
20
votes
3answers
36k 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 ...
19
votes
4answers
37k views

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 followed a tutorial and did this: ln -sf ...
18
votes
10answers
9k views

Shellshock: How do I know if my server is compromised + suspicious files to look out for

Three questions which I hope someone can help answer: How do I know if my server is already compromised due to the Shellshock bug ? If it was compromised, is there a particular folder where I should ...
18
votes
3answers
19k views

How to install libpq-dev on Centos 5.5

In order to develop one web application based on postgresql, i need to install libpq on my centos. I can install it by "apt-get install libpq-dev" on ubuntu, but i can not install it on centos by ...
18
votes
14answers
2k views

Reasons for missing IP info in `last` output on pts logins?

I have five CentOS 6 linux systems at work, and encountered a rather strange issue that only seems to happen with my userid across all the linux systems I have... This is an example of the problem ...
18
votes
4answers
13k views

How to make a global ~/.vimrc?

Right now, I make everyone do ~/.vimrc and put their settings there. How can I make a global, default .vimrc for new users?
18
votes
3answers
20k views

How can I get user name by user ID?

In my FTP client I can see files' owner ID (99). How do I find out which user is the owner of these files?
18
votes
3answers
21k views

My /var/log/btmp file is huge! What should I do?

My /var/log/btmp file is 1.3 GB in size. I've read that the file is "Used to store information about failed login". What does this mean for my server? And can i delete this file?
18
votes
6answers
62k views

What is the value of JAVA_HOME for CentOS?

I have install java through yum on CentOS, however another java programme needs to know what the JAVA_HOME environmental variable is. I know all about setting environmental variables, but what do I ...
18
votes
2answers
40k 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 ...
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 ...
18
votes
11answers
27k 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 ...
17
votes
3answers
2k views

useradd not encrypting passwords in /etc/shadow

I stumbled accross this problem when trying to create new FTP users for vsftpd. Upon creating a new user with the following command and attempting login with FileZilla, I would get an "incorrect ...
17
votes
3answers
39k views

how do you create an ssh key for another user?

I'm trying to create an ssh key for another user. I'm logged in as root. Can I just edit the files generated by ssh-keygen and change root to the user I want?
16
votes
4answers
22k views

How do I patch RHEL 4 for the bash vulnerabilities in CVE-2014-6271 and CVE-2014-7169?

A mechanism for remote code execution through Bash has been widely reported yesterday and today (September 24, 2014.) http://seclists.org/oss-sec/2014/q3/650 Reported as CVE-2014-7169 or CVE-2014-6271 ...
16
votes
4answers
12k views

Failed to instal APC via pecl install APC

Hy when i try to install APC via pecl install APC-3.1.5 or even pecl install APC I get following error when the package comes to the make command: running: make /bin/sh ...
16
votes
5answers
48k views

where are the default ulimit values set? (linux, centos)

I have two CentOS 5 servers with nearly identical specs. When I login and do ulimit -u, on one machine I get unlimited, and on the other I get 77824. When I run a cron like: * * * * * ulimit -u ...
16
votes
4answers
25k views

Upgrade Subversion 1.6 to 1.7 on CentOS? (can't find yum repository)

I want to upgrade my SVN Server from 1.6 to 1.7. Unfortunately I can't find anything on the internet how to do this with yum. I have checked rpmforge-extras but it has only svn 1.6 and not 1.7 I ...
16
votes
2answers
297 views

Identification of physical network interface in linux [duplicate]

I'm new to linux and I have server with four network cards. I have to identify which physical network interface is assigned to the names eth0, eth1, eth2 and eth3. I have to disconnect cable from eth2 ...
16
votes
2answers
10k views

CentOS thinks Disk is busy, can't mount or fsck

I'm a longtime user, and first time question submitter. I've spent a full day searching this and many other sites for a solution, but I must resort to requesting assistance to resolve my situation. ...
15
votes
8answers
62k views

How to send email with my CentOS server?

I just built a modest home server using CentOS 5.5. I want the server to be able to send emails to my Gmail account or other email accounts for various things like cron jobs. Also it would be nice to ...
15
votes
8answers
55k views

How do you re-mount an ext3 fs readwrite after it gets mounted readonly from a disk error?

Its a relatively common problem when something goes wrong in a SAN for ext3 to detect the disk write errors and remount the filesystem read-only. Thats all well and good, only when the SAN is fixed ...
14
votes
7answers
842 views

How to copy a previously entered command using the history utility without running it again?

I am able to use the history command on CentOS to get list of previous inputted commands, however, if I do something like: !372, history will attempt to run the referenced command. I need the ...
14
votes
4answers
5k views

Improving IO with FlashCache

I have a server with 2 HDD's (2x 1 TB), running in RAID 1 (SW-RAID). I want to improve IO performance by using flashcache. There are running KVM virtual machines on it, using LVM. Regarding this, I ...
14
votes
4answers
4k 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 ...
14
votes
1answer
51k views

How to add user with SFTP/ FTP access to '/var/www/html/website_abc' folder on Amazon EC2 Centos?

Possible Duplicate: Linux directory permissions I'm working with some third-party developers and I would like to grant SFTP (or FTP) access to the root folder for a website they're working ...
14
votes
2answers
232 views

NFS poor write performance

I have two machines connected with 10Gbit Ethernet. Let one of them be NFS server and another will be NFs client. Testing network speed over TCP with iperf shows ~9.8 Gbit/s throughput in both ...
13
votes
7answers
13k views

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

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 ...
13
votes
4answers
2k views

/dev/null file became regular file

In our production server suddenly /dev/null became a regular file and due to this sshd service got stopped and not able to login the server. And also we tried to the below steps to configure back to ...
13
votes
1answer
43k 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 ...
13
votes
2answers
287 views

How to uninstall newly installed dependencies for a RPM package?

Is there an easy way to make a list of the dependencies a newly installed RPM package will install with yum? Example: If you do yum install ruby then it will also install some rubygems. But when I ...