Questions specific to the CentOS Linux distribution. Use this tag if your question relates to how the CentOS distribution affects your problem; do not use it if you just happen to be using CentOS and your question is about a specific configuration detail or syntax.

learn more… | top users | synonyms (2)

4
votes
0answers
465 views

Centos 7 boot up with custom kernel problem

I have installed centos 7 on virtualbox machine which has kernel-3.10.0-123.20.1.el7.x86_64. I am trying to build Linux kernel from kernel sources. I downloaded the kernel source files from: ...
4
votes
0answers
765 views

Permission problems. Can't retrieve inbox mails from dovecot

I got a VPS server at a webhoster which has CentOS 6.6 as operating system. Because I have multiple domains which are used by various people this server is going to serve multiple roles: nameserver ...
4
votes
0answers
588 views

selinux, dovecot and sieve

I've just started learning to configure SELINUX and this morning on my CentOS 6.4 x64 system, with postfix/dovecot/mysql installed, I woke up to the following selinux issue found 1 alerts in ...
3
votes
0answers
42 views

Job queueing on a single machine

I have a shiny new server for running simulations on, with a pair of Tesla GPUs and 32 cores, running CentOS 7.2. I'd like for multiple users to be able to submit jobs to the server that get queued up ...
3
votes
0answers
123 views

`yum install` on CentOS 7 states installed size of 578mb, then fails requiring 75+GB more space on /

I have ~10Gb available on /.After running yum install kolab on a new CentOS container yum states the following: Total size: 234 M Installed size: 578 M However, the install then fails with the ...
3
votes
0answers
153 views

Dual Boot Configuration with SSD and HDD

I'm very new to Linux. I have been using Windows/Mac during my whole life, but now I have decided to use Linux. So I'm trying to configure a dual boot system with Windows 10 and CentOS 7. I already ...
3
votes
0answers
105 views

pppd issue over serial cable

I'm trying to set up a ppp connection between 2 computers via serial cable, to enable TCP/IP over serial. Computer1 -> USB-Serial Converter -> Serial Cable -> Serial port of Computer 2 On computer ...
3
votes
0answers
8k views

AH00534: httpd: Configuration error: No MPM loaded

I have a CentOS Linux release 7.1.1503 (Core) system and I have installed httpd and the corresponding configuration file is : # # This is the main rConfig Apache server configuration file. It ...
3
votes
0answers
194 views

Expanding root partition CentOS 6 With using fdisk

I am trying to expand the root partition on a VM which is not using LVM and I do not have (nor want to try and create then use) a disk to boot from. As such I followed what I felt was the logical ...
3
votes
0answers
2k views

How can I reset an unknown root password if a file system check interrupts the startup sequence?

This morning I was helping a fellow admin with a crash that occurred on a CentOS 5.8 VM. Earlier in the day, the underlying SAN hosting various VMs experienced an issue and ultimately caused some ...
3
votes
0answers
820 views

How to disable sudo related logging for successful command execution under CentOS/Fedora?

You can disable sudo related log messages via adding something like Defaults:juser !syslog to our sudoers file. That is disabling logging to syslog. But under e.g. CentOS/Fedora there is an auditd ...
3
votes
0answers
2k views

Samba 4 has high CPU usage when accessing mapped drive through Windows

I have noticed that when I access my Samba share from Windows, the smbd daemon will always use aprox 10-20% CPU - no matter if the share is used or not from Windows. Even if I close the share/window, ...
3
votes
0answers
2k views

Where is module prefork.c settings in Centos 7?

I used to edit the settings in etc/conf/httpd.conf for better memory performance <IfModule prefork.c> StartServers 2 MinSpareServers 3 MaxSpareServers 3 ServerLimit 15 ...
3
votes
0answers
5k views

Understanding “vncserver -list” with respect to Xvnc processes

I have a pretty standard setup on a Centos 6.5 VM. I've configured VNC sessions to start at boot per CentOS's wiki VNCSERVERS="1:root 2:moe 3:curly" VNCSERVERARGS[1]="-geometry 640x480" ...
3
votes
0answers
526 views

iptables hangs at applying rules

I have a set of rules that are supposed to give me the most protection before things like fail2ban and other things are added to the mix. The issue is that although everything checks out in the test, ...
3
votes
0answers
723 views

Microphone not working on Centos 6.5

I have installed CentOS 6.5 on a Dell Insperion with an Intel chip. I first noticed that my microphone is not working on Skype on CentOS although it was working fine with Windows 7 on the same box. ...
3
votes
0answers
65 views

broken filesets after install VLC via RPMFusion

Needed a media player, followed the link on this site Here is the last part of the YUM output; After following the link above, VLC installed and executed fine, but I was left with broken filesets ...
3
votes
0answers
669 views

Give domain users permissions on cifs shares?

I am using CentOS 6.5 - users authenticate using winbind, all are domain users except for root. /home is mapped to a cifs share on a windows server in /etc/fstab with this line: \\server\home$ /home ...
3
votes
0answers
273 views

linux io stack analysis

I'm trying to understand the Linux IO stack by analyzing blktrace trace. Below is the trace i captured by executing simple fio sequential write with no Direct IO (5 x 8k request size). 8,16 1 ...
3
votes
0answers
974 views

How to scroll in a terminal by line in GNOME Terminal 2.31.3?

I use Shift+(PgUp/PgDown) while scrolling in the terminal. But it seems to scroll one screen (or a half may be) at a time. I feel comfortable scrolling the terminal by line with the mouse, but don't ...
3
votes
0answers
922 views

SCSI Tape drive on ubuntu and centos

On ubuntu 12.10 I have those SCSI drives: [1:0:0:0] cd/dvd TSSTcorp CDDVDW TS-H653N 0208 /dev/sr0 [2:0:0:0] disk Generic USB SD Reader 1.00 /dev/sdb [2:0:0:1] disk Generic ...
3
votes
0answers
187 views

Traffic getting routed through Apache

for some reason, certain outgoing traffic on my server gets routed to the apache webserver i am running. this problem just started happening. i have the webserver set up to use vhosts, the webserver ...
3
votes
0answers
604 views

Fedora 14 Xen virtual machine does not detect network

I'm trying to create a para-virt Fedora 14 Xen vm on a host running CentOS 5.5. The VM appears to initially install correctly (the installer finds eth0 and can access the installation media). But when ...
2
votes
0answers
16 views

How do I get Consul to work so I can get Docker Overlay to work?

I am running CentOS 7 with Docker. I am trying to install Consul on the Docker server. Consul is unzipped. The binary file works for showing the version. I ran this: echo $CONSUL_RPC_ADDR This ...
2
votes
0answers
31 views

How to set up thousands of VLANs on ISC DHCP-4.1.1-P1 server?

I have been attempting to set up a DHCP server using ISC DHCP-4.1.1-P1 compiled on CentOS 6.7 The idea is to have multiple thousands of VLANs. I have started small. I have no issue doing ifup on ...
2
votes
0answers
139 views

Install CentOS on RAID (manually) on UEFI system

I'm struggling with the manual configuration of a RAID1 + RAID10. I'm trying the procedure on a VM (VirtualBox 5.0.14 r105127) on OSX 11.10.3. The strategy I took is: The complete set of commands I ...
2
votes
0answers
40 views

Why could policy routing on iptables marks applied in FORWARD or OUTPUT chains be inconsistent?

I am routing HTTPS connections down a SSH tunnel (-w) using iptables marks and iproute2 rules, the reasons I need to do it this way are contrived, to say the least, so most alternate solutions may not ...
2
votes
0answers
75 views

Lost space in LVM

LVM Hey. First of all I want to say excuse me for my bad English. I a problem after installing CentOS 7 with LVM. Some space lost after problem with LVM configuration. I tried to add some logical ...
2
votes
0answers
21 views

lshw HWPath priority — how to determine

I have a project here at work where I'm attempting to definitively map ethernet MAC addresses to physical ports (IE card 1 port 0 is eth0 (mac xx:xx:xx:xx:xx:xx) and a non-technical operator can look ...
2
votes
0answers
28 views

how to build kernel-tools-4.2.xx.rpm and kernel-ltools-libs-4.2.xx.rpm

I am trying to upgrade Centos-7 kernel (kernel-3.10) to (Kernel-4.2.6) and for that I downloaded kernel from kernel.org and create rpm for the custom configuration (arch x86_64)using "make rpm". ...
2
votes
0answers
142 views

NFS mounting options rsize and wsize can't be specified in /etc/fstab

As the Title, the options rsize and wsize can not be specified on Centos7(3.10.0-123.el7.x86_64) cat /etc/fstab: 192.168.11.1:/linux_nfs_share /mnt/nfs01 nfs ...
2
votes
0answers
45 views

Unable to insert records on sqlite on a Linux environment

I tested a simple Php program using Sqlite3 instead of mySQL on my own computer and it works fine. What the program does is simple insert of record into a certain table. Now, when I try to do that on ...
2
votes
0answers
96 views

Unable to start ZNC as a service

Firstly, this is the exact same question as found here, but the given solutions did not work in my situation. Background I am running a CentOS 6 VPS and I want to run a ZNC bouncer on it. I ...
2
votes
0answers
228 views

How to install man pages in CentOS 6.x minimal for all previously installed packages?

I ran into an issue to where man pages were missing from a CentOS 6.x minimal system (this is normal). I installed the man subsystem and then noticed the man pages were still missing for select ...
2
votes
0answers
70 views

How to set YUM settings in a Kickstart?

I am moving a 32-bit CentOS server that runs 32-bit applications to 64-bit CentOS to allow more RAM. I already have a kickstart file that I use, but unfortunately the packages listed have no ...
2
votes
0answers
104 views

CentOS7 on VMware: How to reach Docker service from Host

I want to access the guests docker services via browser with IP:port/service. For example, I'm running a RabbitMQ, which I want to check. Unfortunately I get a ERR_CONNECTION_REFUSED, when trying to ...
2
votes
0answers
155 views

How do I ssh into a new virtual machine?

note by derobert: problem was resolved in chat, starting around http://chat.stackexchange.com/transcript/message/24666451#24666451 if someone wants to write up an answer. Turns out the bridge wasn't ...
2
votes
0answers
157 views

Unable to mount secondary HDD on CentOS 6.7 (Must specify file system?)

I have a secondary HDD that worked fine in Ubuntu 13.04. I had mounted in to /media/user/<some UUID>/. I could read and write files without problem. My Ubuntu installation was on a primary SSD. ...
2
votes
0answers
74 views

Why is denyhosts not banning *some* brute force root SSH login attempts?

I recently noticed in my logwatch emails from a couple of servers that although denyhosts was doing its job for some brute force root ssh login attempts others seem to be ignored and continue to ...
2
votes
0answers
105 views

How to restrict openvpn clients to communicate with other vpn clients

I have this Openvpn scenario.. I have Lot of openvpn clients connected to my server, All i want is to restrict client to client communication. for eg. i have ...
2
votes
0answers
600 views

Could not resolve host: mirrorlist.centos.org

I did a fresh install of CentOS 7 on an Acer Inspire T. It is a terminal-only installation (no GUI). I connected the CentOS 7 box to a cable modem via an ethernet cable, and the cable modem is ...
2
votes
0answers
56 views

How to create a LiveDVD from an installed CentOS?

I have an installed Centos 6.1 64 bit. We need to create a LiveDVD from it. The custom is that it has a few packages installed that cannot be found in repositories. Question: how can I make a ...
2
votes
0answers
64 views

How to get the values for “set root” in menuentry while setting password for GRUB2 on CentOS 7

I need to disable single user mode on my servers running CentOS 7. I read the RedHat documentation on what goes to /etc/grub.d/40_custom and how to encrypt the password and all but one details makes ...
2
votes
0answers
3k views

“xrandr: Failed to get size of gamma for output default” for Guest CENTOS 6.6, HOST OS Windows 7 enterprise

I am getting the following errors: xrandr: Failed to get size of gamma for output default Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1024 x 768 default connected 1024x768+0+0 0mm ...
2
votes
0answers
78 views

Converting a raw print data stream containing PCL commands to PDF

I have a program that sends raw print data through samba to typically PCL compatible printers. The program is written so basic PCL commands control how it prints. When sending it to the printer it ...
2
votes
0answers
777 views

Exundelete can't restore the file

I'm trying to restore 2 important tar.gz files I know their directory but extundelete not restoring them although it's giving me the inode number. Loading filesystem metadata ... 2127 groups loaded. ...
2
votes
0answers
70 views

recover lvm formatted partition

I had 2 old drives having LVM installed showing as 1 drive. They were attached by the datacenter to the new server to migrate data but they weren't able to be mounted I tried everything possible until ...
2
votes
0answers
537 views

Install Centos7 with kickstart file fails with “entering emergency mode”

I've created and tested a kickstart file using virtualbox. However, when I try to use the same kickstart file on a different computer, I get "Warning: Could not boot", "Generating ...
2
votes
0answers
528 views

MySQL read only error but permissions set and SELinux AFAICT correct

I am new to MySQL and Linux and because I had issues with an old MySQL version (5.1) I used mysqldump and installed MySQL 5.6. I changed the datadir location by copying everything to the new folder ...
2
votes
0answers
186 views

Why does my USB modem produce multiple /dev/ttyUSB* files?

I have a single Sierra Wireless USB 308 modem we are using for sending SMS message to, and receiving SMS messages from, customers. When this single device is plugged in, the system creates multiple ...