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.

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4k 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 the sudoers file. That will disable logging to syslog. But under e.g. CentOS/Fedora there is an auditd ...
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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
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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 ...
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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
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0answers
865 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 ...
4
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0answers
1k 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) [...
4
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0answers
1k 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
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0answers
483 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
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0answers
6k 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 ...
4
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0answers
441 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
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0answers
1k 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
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0answers
25k 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
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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
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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
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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
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0answers
486 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
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0answers
18k 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
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0answers
979 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
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0answers
403 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
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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
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0answers
40 views

How to deny crontab to group

I'm trying to deny crontab to group but I had no success so far. Nor I saw how to do it, or even discussions about it. Is it possible to deny crontab to groups instead of users? Imagine if you have ...
3
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0answers
148 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
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0answers
446 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
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0answers
708 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
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0answers
137 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
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0answers
61 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
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0answers
862 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: ...
3
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0answers
114 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
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0answers
337 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
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0answers
993 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
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0answers
719 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
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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
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0answers
176 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
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0answers
271 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) ...
3
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0answers
530 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
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0answers
508 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
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0answers
424 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
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0answers
5k 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
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0answers
547 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
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0answers
674 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
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0answers
5k views

FIPS integrity test failed

I recently enabled the fips module in my CentOS 6 machine using this guide. During reboot, the system halted with this error: SELF TEST FAILED (/usr/lib64/hmaccalc/sha512hmac.hmac) dracut: FATAL: ...
3
votes
0answers
397 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 ...
3
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0answers
1k 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
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0answers
1k 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 "/run/initramfs/...
3
votes
0answers
7k views

nginx: [emerg] “server” directive is not allowed here

I get the following error message when trying to configure server: []# nginx -s reload nginx: [emerg] "server" directive is not allowed here in /etc/nginx/conf.d/hello-world.conf:1 Configuration is ...
3
votes
0answers
491 views

Is there way to print the entered password in PAM?

We are using CentOS 6.5. We have a perl script for our automation testing. One of the script login to the user as non-root user and test "su -" command. This test case passes most of the times but ...
3
votes
0answers
2k views

rp_filter dropping packets in linux bridges+vlan_tagged interface + tap interfaces configuration

I've a linux bridge which has it's first interface as a eth0.123 (VLAN tagged interface) & one or more tap interfaces created by kvm. (libvirt+kvm VM) [root@compute1 ~]# brctl show bridge name ...
3
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0answers
11k views

Redhat / Centos 7 Firewalld best practice for pptp or L2TP/IPsec rules

Having a quick look at Centos 7, and though I'd spin up a VPN daemon or 3, but immediately discovered the usual packages aren't yet in the core repositories, so had to dig around and found the ...
3
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0answers
184 views

Transparent Proxy

I am setting up attempting to set up a transparent proxy on CentOS using Squid. So far I have managed to filter the content and get it working perfectly. The only issue I am having is getting a form ...