Discuss June 2017

discuss@lists.centos.org

90 participants
76 discussions

27 Oct '17

I am a bit of a noob with Linux and Centos but would like to be able to access an old external USB disk formatted JFS by OS/2. I have seen there is a kmod-jfs package on elrepo that ought to work with Centos 6 but am unsure how to install kmods without hosing my existing system... If anyone would like to be so kind to give me a short how-to, I would be very grateful. Thank you.

4 13

NFS mount on Centos 7 crashing
by Nikolaos Milas 20 Oct '17

20 Oct '17

Hello, We have a VM (under KVM - a VPS service by our ISP) running CentOS 7. On it we have 2 NFS mounts, one for backup and one as a live file system (where there are two user homes as well): ----------------------------------------------------------------------------------------------------------------------- # cat /etc/fstab /dev/mapper/centos-root / xfs defaults 0 0 UUID=7a3ae70a-8ef3-463b-8f5b-be4e2e7be894 /boot xfs defaults 0 0 /dev/mapper/centos-swap swap swap defaults 0 0 10.201.40.34:/data/col1/noc-bkups-1 /mnt/dd2500-1 nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0 10.201.40.34:/data/col1/hesperia-mount /hesperiamount nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0 ----------------------------------------------------------------------------------------------------------------------- This setup has been working fine for over a year, even under significant load, without issues. However, yesterday, the "live" NFS mount (/hesperiamount) has started crashing. When bootingeverything is fine, but very soonafter boot we noticed that we lose communication to the mount, although the remote storage system is accessible(without reporting any errors) and no network issues have occurred. We found that dmesg reports failures with call traces (2 examples): https://pastebin.com/GVSDbxFr https://pastebin.com/WujKQuHG This happens repeatedly/consistently (after several reboots) so we have been forced to replace the NFS mount with a local mount (on a new local virtual hard disk), to restore normal system operation. So the fstab has now become: ------------------------------------------------------------------------------------------------------------------- # cat /etc/fstab /dev/mapper/centos-root / xfs defaults 0 0 UUID=7a3ae70a-8ef3-463b-8f5b-be4e2e7be894 /boot xfs defaults 0 0 /dev/mapper/centos-swap swap swap defaults 0 0 /dev/mapper/vg2-lv1 /hesperiamount xfs defaults 0 0 10.201.40.34:/data/col1/noc-bkups-1 /mnt/dd2500-1 nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0 # 10.201.40.34:/data/col1/hesperia-mount /hesperiamount nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0 ------------------------------------------------------------------------------------------------------------------- Note that when I later mounted manually the same NFS share on the same box (in order to copy data from it using rsync), it did not crash (but it only had reads and no writes in this scenario). The share was manually mounted with the following command: # mount -vv -o auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 -t nfs 10.201.40.34:/data/col1/hesperia-mount /hesperiamount2 Questions: * Is this a known issue/bug? * Have we possibly made any NFS misconfigurations (which however have not caused any errors for about a year now)? * What could we do to prevent the error from occurring again? Please advise. Thanks, Nick

3 12

system slowdown
by Larry Martell 13 Sep '17

13 Sep '17

I have a CentOS 6 system that has suddenly starting significantly slowing down. It runs a django app with an Apache server and MySQL server. There is plenty of disk space and no process seems to be hogging the memory or CPU. But operations that used to take 5 minutes are now taking hours and hours. Coinciding with this slow down I see these messages in /var/log/messages (this is hand typed, as I can't copy/paste or send email from this system, although for a change I do have remote access via 2 VPN hops): kernel: BUG: soft lockup - CPU#5 stuck for 67s! [khungtaskd] kernel: BUG: soft lockup - CPU#7 stuck for 67s! [khugepaged] These messages started appearing today around 7 AM, which is when users started reporting the slowdown. They are still occurring periodically and the system is still slow. Are these messages caused by the slowdown or are they the reason for it? Are they useful in tracking down the problem?

2 3

Simple OCSP server ??
by Alice Wonder 05 Sep '17

05 Sep '17

Hello list, I'm contemplating running my own CA to implement the new proposed ISP for validation of S/MIME certificates via DANE. I already use self-signed for my MX servers (with 3 1 1 dane records on TCP port 25) but I don't want to use self-signed for S/MIME for user specific x.509 certs because A) That's potentially a lot of DNS records B) That requires a hash of the e-mail addresses in DNS Instead, I will be using a wildcard in DNS with an intermediary that signs the user x.509 certificates. Using an intermediary to sign their certificates though means I can't just revoke their certificates by removing the DNS certificate, I'll need to provide an OCSP server for when one of their private keys gets compromised. I found https://access.redhat.com/documentation/en-US/Red_Hat_Certificate_System/8.… but it looks like that is intended for enterprise, more complex than I need. Anyone know of a good simple script for providing OCSP ?? -=- Not relevant to question but just important for me to note, I will *not* be asking people to install my root certificate in their e-mail clients. I think it is a bad practice to get users in the habit of installing root certificates. I think the PKI system has way way way to many root certificates as it is. I want a world where DANE validates most certificates, and only a few root certificates are needed for things like banks where EV certificates are a must. DANE as a way to validate S/MIME I think will be a godsend to e-mail security, I hope clients implement it.

2 5

ipa rpm conflicts
by lejeczek 04 Aug '17

04 Aug '17

does anybody see this: unning transaction Warning: RPMDB altered outside of yum. ** Found 8 pre-existing rpmdb problem(s), 'yum check' output follows: ipa-admintools-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-admintools: ipa-admintools-4.4.0-14.el7.centos.noarch ipa-client-4.4.0-14.el7.centos.x86_64 has installed conflicts freeipa-client: ipa-client-4.4.0-14.el7.centos.x86_64 ipa-client-common-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-client-common: ipa-client-common-4.4.0-14.el7.centos.noarch ipa-common-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-common: ipa-common-4.4.0-14.el7.centos.noarch ipa-python-compat-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-python-compat: ipa-python-compat-4.4.0-14.el7.centos.noarch ipa-server-4.4.0-14.el7.centos.x86_64 has installed conflicts freeipa-server: ipa-server-4.4.0-14.el7.centos.x86_64 ipa-server-common-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-server-common: ipa-server-common-4.4.0-14.el7.centos.noarch ipa-server-dns-4.4.0-14.el7.centos.noarch has installed conflicts freeipa-server-dns: ipa-server-dns-4.4.0-14.el7.centos.noarch this in .rpm I guess and started appearing after upg to 7.3. *freeipa* is naming convention Fedora uses, right? Some remnants rebase did not take care of? regards, L.

4 3

installer with centosplus kernel?
by Keith Keller 20 Jul '17

20 Jul '17

Hi all, Is there any way to get a CentOS 7 ISO with the centosplus kernel? I have some very old hardware I'd like to keep going if easy, but it has old NVidia network cards that need the forcedeth driver. Apparently this driver is now in the centosplus kernel, but if I use the default ISO I won't be able to get on the network to get the centosplus kernel. (Of course I can get the kernel to the machine in other ways, but over the network is by far the most convenient.) See https://bugs.centos.org/view.php?id=7359 for more details. I've done other web searches but found nothing more specific than this link. Thanks! --keith -- kkeller(a)wombat.san-francisco.ca.us

3 4

Installing support for Chinese text in Centos 7
by H 18 Jul '17

18 Jul '17

I have just done a minimal installation of Centos7 followed by X Windows and the Mate desktop on a workstation. Although the default language is English, I would like to be able to write Chinese text in various applications. I seem to remember this was very easy to do in Centos 6 and Gnome: possibly only requiring only a simple 'yum groupinstall "Chinese Support"' after which I could use iBus to switch between languages. This does not seem to work in Centos 7. Suggestions? Thank you.

4 14

mdraid doesn't allow creation: device or resource busy
by adam_kalisz 07 Jul '17

07 Jul '17

Dear fellow CentOS users, I have never experienced this problem with hard disk management before and cannot explain it to myself on any rational basis. The setup: I have a workstation for testing, running latest CentOS 7.3 AMD64. I am evaluating oVirt and a storage-ha as part of my bachelors thesis. I have already been running a RAID1 (mdraid, lvm2) for the system and some oVirt 4.1 testing. Now I added 6x 500 GB platters from an old server running Debian 8 Jessie with software RAID of a similar fashion as well. That would unexpectably prevent the system from booting past something like (I copied it from the working setup), I ran it over night, so it was actually about 16 hours: "A start job is running for dev-mapper-vg0\x2droot.device (13s / 1min 30s)" Can it be just some kind of a scan, which takes so long? The current throughput based on time (16 h) and capacity (3 TB) would be about 50 MBps. (Those drives can be pretty slow when writing, dd showed about 30 MBps, the write cache is off.) This is actually repeatable. If I unplug those drives and boot again, it all works. I don't know, if it helps but before that I had two screens full of: "dracut-initqueue[331]: Warning: dracut-initqueue timeout - starting timeout scripts" Well, I proceded without this array, and after it booted I connected the array of 6 hard disks again. They were recognized etc. The problem is, I cannot do much. I can dd from and to the harddrives, I can create and delete partitions but I cannot create an md raid array out of them, I cannot create a physical volume or format them with a filesystem. I even tried overwriting all of those harddrives with zeroes, which worked but didn't help at all with the creation of the array afterwards. mdadm --create /dev/md6 --level=5 --raid-devices=6 /dev/sd[cdefgh]1 "mdadm: cannot open /dev/sdc1: Device or resource busy" with pvcreate, it seems as if there was no device, but I clearly see it in /dev/sdc1... "Device /dev/sdc1 not found (or ignored by filtering)." partprobe yields: "device-mapper: remove ioctl on ST3500630NS_9QG0P0PY1 failed: Device or resource busy Warning: parted was unable to re-read the partition table on /dev/mapper/ST3500630NS_9QG0P0PY (Device or resource busy). This means Linux won't know anything about the modifications you made. device-mapper: create ioctl on ST3500630NS_9QG0P0PY1part1-mpath- ST3500630NS_9QG0P0PY failed: Device or resource busy device-mapper: remove ioctl on ST3500630NS_9QG0P0PY1 failed: Device or resource busy" In some forums, it was suggested, dmraid (yes, the old) could be the trouble. I eliminated this hypothesis (overwritten all with zeroes, fakeraid was never present with these disks). Also multipathd/ dm_multipath could be the trouble, someone suggested. The problem is, if I was to remove device-mapper-multipath, I would loose oVirt-engine, because it has multipath as dependency for some reason. Do you have any ideas? What logs/ information should I provide if you want to have a look into this. Best regards Adam Kalisz

3 2

C7 and spoofed MAC address
by m.roth＠5-cent.us 07 Jul '17

07 Jul '17

Got a problem: a user's workstation froze. He wound up rebooting, without calling me in first, so I dunno. But, and this is a show-stopper, when it came up, it came up with the firmware MAC, not the spoofed one. In /etc/sysconfig/network-scripts/ifcg-eth0, I've got the spoofed MAC address, and a UUID. In the grub.conf, I've got net.ifnames=0 biosdevname=0. But when I logged onto his machine, ip a showed eth0... but with the firmware MAC. And I'm wondering if it went to renew its IP address, and lost the spoofed MAC. That might explain his freezes. Anyway, does anyone have any idea if there's some networkmangler or systemd configuration that would force it to pay attention? Note that my hack to fix it was ifdown eth0/ifup eth0, and it's fine. mark

3 2

AMD Ryzen and CentOS
by Yves Bellefeuille 03 Jul '17

03 Jul '17

I have a new system with an AMD Ryzen 1600 CPU and I'm trying to run CentOS, so far without success. The only information I could find was a post reporting that CentOS 7 would crash during installation on a Ryzen system: https://www.centos.org/forums/viewtopic.php?t=61831 . I tried updating to the latest elrepo "mainline stable" kernel, version 4.11 (by booting from a live CD and using chroot to enter CentOS: that worked), but the system still doesn't work properly. I'm using CentOS 6 but I'll switch to CentOS 7 if that will help. (But I assume that if installing the latest kernel didn't help, neither would going to CentOS 7.) Any suggestions? Is it known whether the next version will work properly with Ryzen? Yves Bellefeuille <yan(a)storm.ca>

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Discuss June 2017