Discuss May 2016

discuss@lists.centos.org

155 participants
149 discussions

Re: [CentOS] Hard drives being renamed
by Miguel Medalha 25 May '16

25 May '16

>> I've run into this with ZFS on Linux. The 'blkid' is useful to identify the >> target device and then add that to your fstab. I don't use device names >> at all anymore, too ambiguous (depending on the circumstance) in my >> opinion. Right. And there are other ways to identify disks unequivocally. Under CentOS, for example, I find the following directories: /dev/disk/by-id /dev/disk/by-path /dev/disk/by-uuid Each one has its optimal use case. It seems to me that in general the ideal would be to use the WWN identifier, which now comes printed on the disk label sticker and uniquely identifies the disk, offering a clear correspondence between physical and logical disks. Under CentOS, the WWN ID of detected disks can be found under /dev/disk/by-id. WWN stands for "World Wide Name". There's a Wikipedia article about it here: https://en.wikipedia.org/wiki/World_Wide_Name "hdparm - I" or even "smartctl -a" will show which /dev/sdX or whatever corresponds to which WWN or other relatively stable ID types. The advantage of WWN is that the ID won't change if you connect the disk to a different controller, for example from a SAS one to a SATA one. In one of my servers, if I unplug a SATA disk from a LSI-Avago SAS controller and I connect it to a Intel onboard SATA controller the ID changes from "scsi-idnumber" to "ata-brand-model-serialnumber" but the WWN remains constant.

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Hard drives being renamed
by Pat Haley 25 May '16

25 May '16

Hi, We are running Centos 6.7 - 2.6.32-573.22.1.el6.x86_64 on a Quanta Cirrascale, up to date with patches. We have had a couple of instances in which the hard drives have become renamed after reboot (e.g. drive sda is renamed to sdc after reboot). One time this occurred when we rebooted following the installation of a 10GB NIC card, another time after we tried to install mellanox drivers (MLNX_OFED_LINUX-3.2-2.0.0.0-rhel6.7-x86_64). Currently we are unable to boot because that drive has been renamed. Our questions are * Has anyone else experienced similar issues? * What can we do to prevent such renaming in the future -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Pat Haley Email: phaley(a)mit.edu Center for Ocean Engineering Phone: (617) 253-6824 Dept. of Mechanical Engineering Fax: (617) 253-8125 MIT, Room 5-213 http://web.mit.edu/phaley/www/ 77 Massachusetts Avenue Cambridge, MA 02139-4301

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Question on 7.2 and weird characters
by Jerry Geis 24 May '16

24 May '16

When I run this command: rm /tmp/jerry.txt rm: remove regular file â/tmp/jerry.txtâ? I get the a with the carrot on top... How do I get back to the normal characters ? echo $TERM linux Thanks, Jerry

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/etc/sysconfig/iptables syntax
by Mike 23 May '16

23 May '16

The last two router/firewall servers I had used Slackware and Gentoo. I'm used to writing complete and explicit iptables rules; however, when I set up /etc/sysconfig/iptables in CentOS 7 my usual syntax is unusable. For example, I'm used to stating postrouting masquerade as: /usr/sbin/iptables -t nat -A POSTROUTING -o eth0 -s 10.10.10.0/24 -j MASQUERADE But when I use the rule above, iptables.service fails upon start and exits. Through a series of trial and error, I found a correct masquerade statement: *nat -A POSTROUTING -o eth0 -s 10.10.10.0/24 -j MASQUERADE COMMIT This looks similar to output from iptables-save. Another example: /usr/sbin/iptables -t filter -A FORWARD -i eth0 -s 192.168.0.0/16 -j DROP [DOES NOT WORK] *filter -A FORWARD -i eth0 -s 192.168.0.0/16 -j DROP COMMIT [DOES WORK] After using iptables for a long time, I can't figure out where this syntax comes from. Can anyone point me in the right direction to understand the proper syntax necessary in /etc/sysconfig/iptables? Thanks for your help.

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Badlock bad luck
by Bob Smith 23 May '16

23 May '16

I had exactly the same problem. Your workaround fixed me too. With the new samba packages my samba\logs are full of errors. If I temporarily disconnected the PC client NIC cable, and logged into the domain using cached credentials, then I could get past the problem. But, you helped me greatly with this posting. I wasted hours checking Windows updates - useless. We still need the new configuration settings for our conf file to workaround this problem. Bob Smith bobsmith at dbata dot com >* Am 13.04.2016 um 07:51 schrieb Mogens Kjaer <mk at lemo.dk <https://lists.centos.org/mailman/listinfo/centos>>: *> >* Hello, *> >* I run a CentOS 6 machine with samba, serving approx. 150 Windows users with samba running as an NT-like PDC. *> >* After today's samba update (samba-3.6.23-30.el6_7.x86_64 etc.), nobody can log in. *> >* They all get the "Trust relationship failed" error message. *> >* If I downgrade: *> >* yum downgrade samba-common samba-winbind samba-winbind-clients samba-client samba samba-doc samba-domainjoin-gui libsmbclient *> >* - the problem goes away. *> >* What am I missing? *> >* Mogens *> >* -- *>* Mogens Kjaer, mk at lemo.dk <https://lists.centos.org/mailman/listinfo/centos> *>* http://www.lemo.dk <http://www.lemo.dk> *>* _______________________________________________ *>* CentOS mailing list *>* CentOS at centos.org <https://lists.centos.org/mailman/listinfo/centos> *>* https://lists.centos.org/mailman/listinfo/centos <https://lists.centos.org/mailman/listinfo/centos> *

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Re: [CentOS] /etc/sysconfig/iptables syntax
by Barak Korren 23 May '16

23 May '16

בתאריך 23 במאי 2016 05:56,‏ "Mike" <1100100(a)gmail.com> כתב: > > > After using iptables for a long time, I can't figure out where this syntax > comes from. > Can anyone point me in the right direction to understand the proper syntax > necessary in /etc/sysconfig/iptables? > The syntax comes from the output of the 'iptables-save' command. You can configure 'iptables' from the command line as you normally would and then run iptables-save > /etc/sysconfig/iptables On centos<=6 the init.d script also included a 'save' command to do it for you, I'm not sure about the systemd unit file though. HTH, Barak _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > https://lists.centos.org/mailman/listinfo/centos

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Centos 7.2: Mount one by one (not simultaneously!) two usb disk with same label
by Dario Lesca 23 May '16

23 May '16

For backup, I have 2 usb disk with same label (LABEL=bove-bk) mounted periodically one by one (not simultaneously!) in the same folder /mnt/bove-bk/ > [root@s-virt ~]# grep bove-bk /etc/fstab > LABEL="bove-bk" /mnt/bove-bk xfs defaults,nofail 0 0 With Centos 5/6 this has never given problems, now with c7 when I unmount and unplug the first disk and I plug and mount the second I get this message log and the disk is not mounted: > [root@s-virt ~]# mount -a > mag 18 10:18:20 s-virt.bove.local kernel: XFS (sdd2): Mounting V4 Filesystem > mag 18 10:18:21 s-virt.bove.local kernel: XFS (sdd2): Ending clean mount > [root@s-virt ~]# mag 18 10:18:21 s-virt.bove.local systemd[1]: Unit mnt-bove\x2dbk.mount is bound to inactive unit dev-disk-by\x2dlabel-bove\x2dbk.device. Stopping, too. > mag 18 10:18:21 s-virt.bove.local systemd[1]: Unmounting /mnt/bove-bk... > mag 18 10:18:21 s-virt.bove.local kernel: XFS (sdd2): Unmounting Filesystem > mag 18 10:18:21 s-virt.bove.local systemd[1]: Unmounted /mnt/bove-bk. In every way that I try to mount the disk (by UUID, into another folder, using the device, ecc), always systemd Unmount my disk. After some research I have found that by running these commands: > [root@s-virt ~]# journalctl -f & > [root@s-virt ~]# udevadm control --reload > [root@s-virt ~]# systemctl daemon-reload > mag 18 10:28:31 s-virt.bove.local polkitd[1035]: Registered Authentication Agent for unix-process:25607:464417949 (system bus name :1.18421 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale it_IT.utf8) > mag 18 10:28:31 s-virt.bove.local systemd[1]: Reloading. > mag 18 10:28:31 s-virt.bove.local systemd[1]: [/usr/lib/systemd/system/firstboot-graphical.service:14] Support for option SysVStartPriority= has been removed and it is ignored > mag 18 10:28:31 s-virt.bove.local systemd[1]: Configuration file /usr/lib/systemd/system/auditd.service is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway. > mag 18 10:28:31 s-virt.bove.local systemd[1]: Configuration file /usr/lib/systemd/system/wpa_supplicant.service is marked executable. Please remove executable permission bits. Proceeding anyway. > mag 18 10:28:31 s-virt.bove.local polkitd[1035]: Unregistered Authentication Agent for unix-process:25607:464417949 (system bus name :1.18421, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale it_IT.utf8) (disconnected from bus) the mount of second disk work property > [root@s-virt ~]# mount -a > mag 18 10:28:36 s-virt.bove.local kernel: XFS (sdd2): Mounting V4 Filesystem > mag 18 10:28:37 s-virt.bove.local kernel: XFS (sdd2): Ending clean > mount[root@s-virt ~]# It's possible resolve this annoying issue and restore old c5/6 behavior to allow a normal user to substitute the disks from graphical console? Many thanks. -- Dario Lesca (inviato dal mio Linux Fedora 23 Workstation)

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Re: [CentOS] Upcoming OwnCloud changes
by Chuck Munro 23 May '16

23 May '16

Just a FYI folks ... I am running OwnCloud 9.0.2 on CentOS 6.7 and php-7.0 with no issues. I installed the Webtatic repo which has several versions of PHP available for CentOS 6 and 7. I then used the official OwnCloud ce:stable repo to add the cloud software. In a leap of faith, and because this CentOS VM doesn't run anything other than OwnCloud, I used the 'php70w' PHP repo and have had no problems at all. The OwnCloud server is very lightly loaded so I have not had an opportunity to stress test it and have not tried to use MySQL (I configured it with the standard CentOS SQLite). YMMV of course, especially if you're running other PHP applications! Chuck

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devtoolset-4
by Jarosław Bober 22 May '16

22 May '16

Hello, my name is Jarek I am new here. I need some clarifications on how to distribute an app developed with devtoolset-4 enabled. I am developing a distributed app in c++ I wanted to upgrade toolchain to use new standard. Is it true that when I compile on centos 6.x with devtoolset enabled then I will be able to run this app on centos 7.x as well? Do I have to install devtoolset on all my machines that I want to run this app? Or would it use built-in libstdc++ library, linking statically only the missing parts? This confuses me a bit. Regards, -Jarek

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DOS line ends on /var/log/boot.log on CentOS 6.7 ?
by Kay Schenk 21 May '16

21 May '16

Hello all -- Recently, I'm seeing DOS line ends, ^M, on my /var/log/boot.log file. Honestly, I don't check this very often so I can't say exactly when this occurred. Is this just MY experience or are others seeing this also. Additionally, boot/log seems very sparse. Is an old issue still in force on this? https://www.centos.org/forums/viewtopic.php?t=17313 Should I get the updated script from CentOS Plus? Thanks for any help. -- ---------------------------------------------------------------------- MzK "Time spent with cats is never wasted." -- Sigmund Freud

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