Discuss January 2018

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89 participants
70 discussions

/boot partition too small
by KM 02 Oct '19

02 Oct '19

First off - let me say I am not an administrator. I need to know if there is an easy way to increase my /boot partition. When I installed CentOS 6 after running 5, it was my oversight not to increase the /boot size. it's too small and I can't do yum updates. if it's not easy to actually increase it, is it safe to take a chunk in my root filesystem (like /new.boot or something) and just mount it as /boot from now on so it uses the space or is that not a good idea? I am sure I could easily copy the rpms/kernel stuff over to it and then unmounts the real /boot and mount this new area as /boot. Can you administrators let me know what you think of all this? Thanks in advance. KM

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Re: [CentOS] BUG: soft lockup - CPU#0 stuck for 36s! [swapper/0:0]
by KM 25 Apr '18

25 Apr '18

All,This happens on all of our CentOS 7 VMs. but as stated in the email trail, the file softlockup_thresh does not exist. Should it be added? What is the best way to get rid of this behavior. Thanks in advance and sorry if I missed something along the way.KM From: correomm <correomm(a)gmail.com> To: CentOS mailing list <centos(a)centos.org> Sent: Thursday, August 18, 2016 1:55 PM Subject: Re: [CentOS] BUG: soft lockup - CPU#0 stuck for 36s! [swapper/0:0] Yes, I tried it, but does not exists: vmguest # cat /proc/sys/kernel/softlockup_thresh cat: /proc/sys/kernel/softlockup_thresh: No such file or directory On Thu, Aug 18, 2016 at 2:06 PM, Carlos A. Carnero Delgado < carloscarnero(a)gmail.com> wrote: > 2016-08-18 12:39 GMT-04:00 correomm <correomm(a)gmail.com>: > > > This bug is reported only on the VM's with CentOS 7 running on on VMware > > ESXi 5.1. > > The vSphere performance graph shows high CPU consume and disk activity > only > > on VM's with CentOS 7. Sometimes I can not connect remotely with ssh > > (timeout error). > > > > I'm also seeing those errors in several servers, running under 5.5. > Currently investigating if this > <https://kb.vmware.com/selfservice/microsites/search. > do?language=en_US&cmd=displayKC&externalId=1009996> > has anything to do (the resource overcommit bit). > > HTH, > Carlos. > _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > https://lists.centos.org/mailman/listinfo/centos > _______________________________________________ CentOS mailing list CentOS(a)centos.org https://lists.centos.org/mailman/listinfo/centos | | Virus-free. www.avg.com |

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OpenVPN server and firewalld
by Kenneth Porter 25 Apr '18

25 Apr '18

How do I insert the iptables rule below using firewalld? I'm moving up from CentOS 6 to 7 on an office gateway and I'm trying to get OpenVPN working to allow home workers to access PCs at the office. I've got it all working but only by manually inserting an ACCEPT rule in the FORWARD iptables chain: iptables -I FORWARD 3 -i tun+ -j ACCEPT This rule was extracted from my iptables firewall under CentOS6. The 3 puts it after the accepts for established connections and loopback connections, but before any firewalld sub-chains. With this I can connect to an internal Windows 10 system with Remote Desktop. How can I inject this rule using firewalld, either as a direct rule or as some more firewalld-approved kind of rule?

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USB audio on Centos-7
by Fred Smith 23 Apr '18

23 Apr '18

I'm using Centos-7 on my PC, with ASUS motherboard. internal audio has always worked fine EXCEPT that I can never get audio input (for recording) to work. I want to feed audio from a phono turntable and from a cassette deck. I use a phono preamp for the turntable, or directly connect the tape deck. but either nothing, or low level with horrible distortion. so, I gave up (after years of intermittent battles) and bought a Behringer UFO202, which looks like it should work fine with Linux. It allegedly uses a TI PCM2902 chipset, which many online postings claim works fine with various flavors of Linux. This device has a USB port, a pair of line in and line out jacks, a phono jack, a headphone volume control, and a switch to change the line in to phono in. I can use headphones plugged into the UFO202 to listen to audio playing on the computer, but I cannot for the life of me figure out how to feed audio into the UFO202 (via its line in RCA jacks) and have it come out speakers or phones connected to the computer. I've poked and proded at alsamixer, the mate sound tool, and pavucontrol. No useful results. Pavucontrol, in its input section, does show the device listed, and it shows activity on its level mater when there is audio input via the line in jacks on the UFO202. Disconnect the line input and the activity ceases. (Mate sound control also lists the device, but I don't even get an indication of any input at all, as I described above for pavucontrol.) but I simply cannot figure out how to get that audio to play in any audible way. I know that USB audio input works, because I have a Plantronics USB headset with microphone that I use often to converse online, and it works nicely. (and a possibly separate issue: how the heck does one point Audacity to a USB input? Can't find anything in its UI, and there's darn little help online that is actually helpful, in this regard.) Can you sense my frustration here? I'd appreciate any help that is actually helpful,... perhaps someone who reads this actually has one of these things and has made it work? thanks in advance! Fred -- ---- Fred Smith -- fredex(a)fcshome.stoneham.ma.us ----------------------------- God made him who had no sin to be sin for us, so that in him we might become the righteousness of God." --------------------------- Corinthians 5:21 ---------------------------------

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/lib/firmware/microcode.dat update on CentOS 6
by Valeri Galtsev 06 Apr '18

06 Apr '18

Dear All, An update just brought on my CenOS 6 boxes updated microcode.dat files: /lib/firmware/microcode.dat Does anybody know off hand what (how critical) is that, as, if it is related to most famous these days trouble with CPU hardware, I will need to reboot relevant boxes to have new microcode loaded. But if it is not that critical, it can wait till next reboot. Thanks a lot and apologies for laziness (not looking into details of this particular update myself). Valeri ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++

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kmod c74 broken: howto report it
by Stijn De Weirdt 14 Feb '18

14 Feb '18

hi all, latest kmod update 20-15.el7_4.6 is broken on our systems, while previous 20-15.el7_4.4 was working fine (and downgrading fixes the issue). the issue is with modules from mellanox kmod rpms that are symlinked in the weak-updates dir. the config files in /etc/depmod.d look ok (and do work with previous version): dist.conf has weak-updates after built-in, and mellanox kmod rpms ship a config that overrides it for all modules. anyhow, before i try to get this upstream, how do i report this with centos team (to make sure the centos kmod rpm was correctly build). (i have already asked here before how to properly report it, but can't find my previous mail ;) stijn

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What is best way of managing isolated network environment?
by Xinhuan Zheng 01 Feb '18

01 Feb '18

Hello, We need to manage isolated network environment so that even though host name and ip address could be same, but they are located in isolated network environment so that’s not a problem. However, that would be very challenging to build a server in such an isolated environment. For example, we could do kickstart to build a server in non-isolated network environment, but for isolated one, we don’t have such a kickstart server. If we had such one, that would mean we consume more resources for building server. What is best way of managing such isolated environment in terms of easily building servers? Thank you, - xinhuan

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Xen hypervisor on CentOS 7.4 with modern UEFI server not booting from grub
by John Naggets 01 Feb '18

01 Feb '18

Hi, I installed CentOS 7.4 on a modern Lenovo ThinkSystem SR630 server which uses UEFI. So far so good CentOS 7.4 works fine so then I went on to install the Xen hypervisor by following the instructions from the wiki (https://wiki.centos.org/HowTos/Xen/Xen4QuickStart) Unfortunately when I reboot after having installed the xen package the system does not boot into "CentOS Linux, with Xen hypervisor" from the grub menu prompt. I get the following error: Loading Xen 4.6.6-8.el7 ... error: can't find command `multiboot'. Loading Linux 4.9.75-29.el7.x86_64 ... error: can't find command `module'. Loading initial ramdisk ... error: can't find command `module'. Press any key to continue... The problem which I encounter here is exactly the same issue as described for Fedora in the RedHat bugs: https://bugzilla.redhat.com/show_bug.cgi?id=1286317 with the exception that for me it's CentOS 7.4 and that the workarounds as described in that bug do not work. Does anyone know how I can make my CentOS boot with the Xen hypervisor using UEFI? Thank you very much for your help. Best regards, John

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best centos server setup for graphics intensive kvm vms?
by Morgan Read 01 Feb '18

01 Feb '18

Hallo list I've been running fedora for donks as my production laptop os, but now I want to set up one of those old laptops to run as a home server running a number of home type vm appliances. I don't want to risk having to tear down and rebuild the setup every 6 months to a year - so, figure centos is my best canditate to run as a stable server. The sort of home type vms I envisage running include: LibreELEC https://libreelec.tv/ Vortexbox https://wiki.vortexbox.org/available_images ownCloud https://owncloud.org/download/#owncloud-server-appliance freeSwitch https://freeswitch.org/pages/vm.html Etc... Without wanting to start a very competative discussion - what would be a suggested minimal centos 7 install to provide such a server? My main area of confusion is whether I need a gui on the server for kodi? Many thanks for any answers to this wildly open ended question! M -- Morgan Read E mstuff(a)read.org.nz

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How is initrd.img packed and compressed?
by Mircea Husz 01 Feb '18

01 Feb '18

Hi, In order to work around a known upstream bug I needed to add a udev rule to pxeboot initrd.img on CentOS 7. The process is straightforward: 1 - extract the pxeboot initrd.img to a new directory 2 - add the udev rule needed to fix the bug 3 - pack and compress it back in initrd.img format The resulting updated image works, it fixes the upstream bug and life is good. But although it works, it's not the same format as the original initrd.img that ships with the distro. I would like to know the proper incantation used to package initrd.img Now for the specifics. The original image: http://mirror.steadfast.net/ centos/7.4.1708/os/x86_64/isolinux/initrd.img is extracted: /usr/lib/dracut/skipcpio initrd.img | xzcat | cpio -i -d and after adding the needed udev rule, it gets packed and compressed as follows: find . 2>/dev/null | cpio --quiet -c -o | xz -9 --format=lzma >"~/patched-initrd.img" Now for the difference. FIrst the original distro image: # file initrd.img initrd.img: xz compressed data # file patched-initrd.img patched-initrd.img: LZMA compressed data, streamed Without the --format=lzma flag it fails to boot. Does anyone know how this is done properly ? Thanks, -Mike

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Discuss January 2018