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Questions tagged [centos]

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.

7
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0answers
3k 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 ...
5
votes
0answers
4k 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. ...
5
votes
0answers
1k views

Why don't I hear audio playing from my CentOS 6.5 Vagrant box?

I want to play a wave file from my CentOS 6.5 Vagrant box using aplay and of course I want to hear the sound. This is what I do: > aplay sine.wav Playing WAVE 'sine.wav' : Signed 16 bit Little ...
4
votes
0answers
697 views

kernel: pci 0000:7f:12.4: BAR 3: failed to assign [mem size 0x00000010]

My host machine is always stuck recently. and sometimes also black screen. And when I start my host machine(CentOS 7.2), it records those information in the /var/log/messages: The logs is below: ...
4
votes
0answers
776 views

SMTP Server Dovecot / Exim Authentication error

Recently, I've installed the centOS 6. The purpose of the installation to use this server as Mail server. Where I've installed Exim version 4.84_2 #1 and Dovecot. I've followed this blog post and I'...
4
votes
0answers
234 views

Logitech controller not passing into Centos virtual machine as joystick

I have a Logitech Dual Action Controller that I am trying to use in a Centos virtual machine (using VirtualBox). The controller is in "D" mode (according to the switch on the back of the controller) ...
4
votes
0answers
419 views

Mail Server user management issue using Postfix+Dovecot+RainLoop

I'm using mail server using postfix+dovecot (over TLS/SSL), RainLoop as my WebClient, and using auth-system.conf.ext so user's password will be read by/from pam. Consider at least 10 users using this ...
4
votes
0answers
417 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 ...
4
votes
0answers
932 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 ...
4
votes
0answers
24k 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 ...
4
votes
0answers
1k 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: http://...
4
votes
0answers
1k views

blocking all but specific ips from specific services in CentOS 7

In a CentOS 7 web server that needs to remain totally closed to the public, I need to block all ip addresses and then only allow specified ip addresses to access specified services. How can I ...
4
votes
0answers
5k 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 ...
4
votes
0answers
471 views

TPM passwordless boot

I'm trying to create device with CentOS6, encrypted disk (with LUKS), TPM module and TrustedGRUB to boot securely and without interaction. I'm following instructions from https://github.com/shpedoikal/...
4
votes
0answers
2k 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, ...
4
votes
0answers
17k views

Ping command results in packet loss

Whenever I ping on my personal computer, nothing gets displayed other than a single statement. Upon stopping execution, I see that several packets were transmitted in the statistics. On top of all ...
4
votes
0answers
959 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 ...
4
votes
0answers
395 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 ...
4
votes
0answers
1k views

How can I tell if no_root_squash is enabled from an NFS client without mounting the share?

Obviously, I can look at /etc/exports on the NFS server-side to see if no_root_squash is enabled, but is there a way I can check this from the NFS client-side without actually mounting the share? ...
3
votes
0answers
64 views

~1000ms latency touching file on nfs mount

I have an NFS mount where the server is on the same subnet as the client. When I time touch testempty from the client, I get: touch testempty 0.00s user 0.00s system 0% cpu 1.325 total The time ...
3
votes
0answers
349 views

How do you enable the secret-tool command (backed by gnome-keyring, libsecret and dbus) in a headless CentOS Docker container?

I'm trying to use the secret-tool command to store a secret securely in a running headless CentoS 7.5.1804 Docker container, but can't seem to find which packages and/or configuration is necessary to ...
3
votes
0answers
532 views

Centos 7 AD authentication DataProvider is Offline

I have configured my Linux machine to use AD authentication. Sometimes few nodes are unable to login. The /var/log/sssd/sssd_nss.log log file reports the message below: Thu Sep 13 13:31:39 2018) [...
3
votes
0answers
262 views

Centos 7 stopped detecting all RAM on system?

After months of working fine, the BIOS for my Centos 7 installation suddenly maps the wrong amount of memory to the kernel. I have 8 GB of RAM installed and the SO only maps 3.2 GB of RAM. I can't ...
3
votes
0answers
490 views

auto groups in CentOS 7 in Active Directory domain?

I am having an issue that might be mostly cosmetic but I've gotta keep the user complaints down. :) I have a set of servers running CentOS 7.4 and have the requirement to join the servers to an ...
3
votes
0answers
95 views

Set up env variable when sudo as apache user

I have centos 7 webserser, all site's files within \www\sitename\htdocs\ belong to user 'apache'. Sometimes i need git pull as apache user, that's why i wrote simple script to sudo as apache: [...
3
votes
0answers
45 views

Secondary Monitor displaying only mouse on Centos 7

I recently switched to Centos 7, but when I connected my secondary monitor through HDMI, something wierd's happening. GNOME's able to recognize that the second one has been connected, but I can only ...
3
votes
0answers
82 views

Anyone know where to change this “bufsize” value? ( st / mt LTO tape drives )

I am trying to speed test some new LTO tape drives but cannot seem to send data to the tape via dd for any block size above 327,680 bytes. I must have a 1M blocksize for my application. [root@host]# ...
3
votes
0answers
84 views

cgroup throttle on child device does not work

I'm running Docker containers with devicemapper on CentOS 7 (3.10.0-514.10.2.el7.x86_64). For some containers I can easily throttle reads through blkio.throttle.read_bps_device by specifying the ...
3
votes
0answers
279 views

XDMCP “maximum number of open sessions from your host reached” but no session is active

I'm using XDMCP to access CentOS 6 hosts from Cygwin/X. Everything works fine, but every now and then attempting to connect results in the error message: XDMCP fatal error: Session declined maximum ...
3
votes
0answers
5k views

How to configure snmptrapd to process incoming traps from a Juniper device?

I have a CentOS server (7.2). I am trying to configure this as a SNMP trap receiver. In my snmptrapd configuration, I am calling a very basic shell script just to identify if the trap was received: [...
3
votes
0answers
812 views

How to define multiple routes for KVM guests with CentOS 7

The code below generates two CentOS 7 GUEST virtual machines on a CentOS 7 HOST. One of the virtual machines is connected to the internet via a PUBLIC IP address. The other is given a PRIVATE IP ...
3
votes
0answers
636 views

Samba Share with OpenLDAP Users

I want to have following Setup: OpenLDAP Server where Users are stored. File Server with Samba Shares, where OpenLDAP Users should have access to. OpenLDAP Users already have access too several ...
3
votes
0answers
1k views

httpd failed due to SSLProtocol: Illegal protocol 'TLSv1.1' on centos 6.7

I am trying to update TLS1 to TLS1.1 or higher but after doing below changes, Getting error "SSLProtocol: Illegal protocol 'TLSv1.1'" My Apache and openssl version are :- httpd -v Server ...
3
votes
0answers
405 views

Port 443 switching to filtered after openssl test

While I was investigating this issue related to SSL (published as OT in StackOverflow), I found a curious behaviour. Premise The premise is that I was trying to understand why my web server (hosted ...
3
votes
0answers
355 views

docker run from systemd service starts but exits immediately, and restarts, but docker run from shell works fine

On my CentOS 7.2 box, with Docker 1.10.3, I successfully tested the following (running as root): docker run --name usljavadoc_server -p 80:80 -p 443:443 -v /opt/app/uslJavadoc/:/var/www/html/ -d ...
3
votes
0answers
169 views

snapshot linux vmware guest from within vm

Is it possible for a Linux VM guest to request that the host make a snapshot of itself, using just the open-vm-tools suite. I see references that seem to indicate that it's possible, no examples. My ...
3
votes
0answers
102 views

How to run Amazon CLI “glacier” under Python 2.7 on Centos6?

On Centos 6 after installing Amazon's CLI tools using pip: # glacier vaults Result: ssl.SSLError: [Errno 1] _ssl.c:492: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify ...
3
votes
0answers
159 views

Larger number of context switches for kondemand

According to the documents on the web, kondemand is responsible as cpu scaling governor. kondemand is a kernel thread that belongs to the ondemand governor of cpufreq subsystem, which changes the ...
3
votes
0answers
472 views

r8169 stops working after a while

This issue appeared after the CentOS installation. Server becomes unavailable completely neither through ssh nor through smb protocol. It happens randomly and there is no exact regularity. It can ...
3
votes
0answers
642 views

DHCP Server:multi subnet not working

I want to let DHCP server offer different subnet address to different group of mac address. I have been successful to offer multi subnet addresses to DHCP clients. I have used the "class" as filter ...
3
votes
0answers
2k views

How can I completely remove software raid?

I have an install of CentOS 6.5 which was setup with software raid (as outlined in this official documentation). There are 3 hard drives and I have RAID1 running: NAME MAJ:MIN RM SIZE RO TYPE ...
3
votes
0answers
435 views

Nagios - Help with getting NRPE to work with check_fail2ban.sh

I am trying to monitor fail2ban with Nagios so, I found the following check via a Google search: http://nagios.fm4dd.com/plugins/manual/check_fail2ban.htm I am trying to get the check to work on a ...
3
votes
0answers
373 views

Second battery either not charging or charge not detected

I have installed Linux on my laptop and running it as the only system. It displays both batteries on the desktop UI, with the first one on 100% and second 0%. When it is discharged it just discharge ...
3
votes
0answers
3k views

Enable touch screen on CentOS 7

I have CentOS 7 installed as a guest OS inside VirtualBox running in a Windows 8.1 host machine. The host is a notebook computer with a touch screen. The windows host can accept touch screen ...
3
votes
0answers
5k views

rpcbind/nfs fails, failed to create RPC listeners, exiting

My system crashed while a script was running that deploys a pxe boot system (software is called DRBL). Now I can't get rpcbind, nfs, or ypbind to start properly. I'm chasing a series of errors which ...
3
votes
0answers
4k views

Failed to start Crash recovery kernel arming

When trying to login into CentOS 7 either through the Gnome GUI or the login shell, I get this: After a second, I get booted backed to the login shell, or login screen of Gnome. I've tried booting ...
3
votes
0answers
488 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 error:...
3
votes
0answers
601 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
359 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 ...
3
votes
0answers
1k views

EXT4 Journaling - Problem

Basically my root (/) ext4 partition keeps being mounted as read-only when I apply internal journaling feature. I understand that this should be default, but today I had been trying to apply external ...