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mount: unknown filesystem type '(null)' error
by Tim Dunphy 13 Oct '15

13 Oct '15

Hey guys, I'm trying to mount a disk volume on aws under CentOS 7. And when I try I get this result: [root@repo:~] #mount /dev/xvdf1 /opt/repo mount: /dev/xvdf1 is write-protected, mounting read-only mount: unknown filesystem type '(null)' The only thing I can see in dmesg that seems to relate is: [ 2481.434610] EXT4-fs (xvdf1): VFS: Can't find ext4 filesystem [ 2509.883144] EXT4-fs (xvdf1): VFS: Can't find ext4 filesystem What can I do to get around this poblem? Thanks, Tim -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

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Centos 6.7 on Tyan Tiger MPX, Graphics and eArrayDirector
by H 13 Oct '15

13 Oct '15

I am a newcomer to Centos and could benefit from some help. I am repurposing an older server and installed Centos 6.7 on a Tyan Tiger MPX 2466 motherboard. The installation went flawlessly but the graphics chip on the motherboard is obviously quite old, a Matrix Millennium MGA 2064W, and the slow default driver (VESA?) was installed. Is a faster video driver available? It would be nice to be able to run the desktop more smoothly... The graphics chip has 8 MB of memory. I Googled but did not find a driver. Is this VESA driver the reason the monitor, an Acer S230HL, is not identified but shown as Unknown in the monitor setup? This machine will be hosting the LSI eArrayDirector client and server for two DF4000 fiber channel diskarrays. Unfortunately this Java application cannot be installed on Centos 6.7 but I am hoping there might be some user who have been able to work around this limitation by installing eArrayDirector on another system and then moving the installation to a later Centos version. Comments and suggestions welcome! Thank you.

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Annoying license at install
by david 12 Oct '15

12 Oct '15

Folks I have several remotely-located servers, donated by folks not all of whom are computer geeks, let-alone Linux aware. In earlier versions of Centos, I directed them to perform a minimal NetInstall (not too difficult to direct over the phone), and then issue two commands after the first boot. One was a 'curl' to download a script of mine, and the second was a dot-command to run it. A few reboots followed in close succession, and I directed them to logon as root, and issue a simple dot-command. The personal intervention ended usually within an hour, since I had ssh access to the system and root, and could complete the installation and tailoring completely remotely. I would only need their intervention in the case of problems. In many cases, I've not needed to invoke that help for a year or more. This scheme worked well until I decided to add support of graphical desktops on the systems in Centos 7, as I had in Centos 6. Once those packages were installed, further non-intuitive on-site intervention was required at next reboot to approve licenses. Remote ssh logins didn't work until that was done. These licenses needed to be approved on the local console. This is quite annoying and places more demands upon my remote friend. In some cases, the console and keyboard had been removed and the box had been placed in the closet. I am seeking a way to reduce or eliminate this annoyance. The best would be to find some way to 'pre-approve' the license agreement in my customizing scripts. Failing that, it would be nice to be able to approve these scripts from a remote ssh logon. I am reluctant to deploy Centos 7 without GUI support (I use x2go sometimes), and am thus reluctant to deploy centos 7 at this point. Advice and comments welcome David San Francisco

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problem on exceptional quit
by Hua Wang 12 Oct '15

12 Oct '15

Dear Centos Users: I installed Centos 7 on my server a few months ago. While using ssh, there is always a strange message "Write failed: Broken pipe”. It forces quit of SSH. It’s really annoying as it happens very often with irregular time interval - from a couple of minutes to a few hours. I have been working using Linux (Red Hat, Fedora and Centos) over 15 years. This didn’t happen for me even under centos 6.6. I have tried the following approaches, but none of them can help. I wonder if it can be solved by reinstall the system again. But it’s time consuming to reinstall a lot of softwares. 1. Login via Mac, Windows, Linux systems from different computers. 2. Modify sshd_config on the server as suggested by many posts: TCPKeepAlive yes ClientAliveInterval 60 3. Modify ~/.ssh/config file on my local computer: Host * ServerAliveInterval 60 4. Login ssh using -Y instead of -X. 5. add ‘unset autologout’ in my .cshrc. 6. I checked IP address with the internet administrator, and it works well. 7. add a file named autologout.csh with ‘set autologout=0’. Do you know a good solution? Thanks! Cheers, Hua ----------------------------- Hua Wang, Ph.D. in Geodesy Department of Surveying Engineering, Guangdong University of Technology, 100 Waihuan Xi Rd., Panyu District, Guangzhou, 510006, China. Tel: +86-13570019257 Email: ehwang(a)163.com Homepage: http://homepages.see.leeds.ac.uk/~earhw

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Dnsmasq
by Gabby Soberano 12 Oct '15

12 Oct '15

Looking for some feedback. Anybody using dnsmasq for dns/dhcp in enterprise level (300-500) users and machines? We have a mix of osx and linux machines. Have AWS instances as well (compute farm). Thanks -g

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Clustering and ha planning
by Leandro 11 Oct '15

11 Oct '15

Hello , Centos users: My name is Leandro, I have been using Centos for 4 years and this is the first post in this mail list. I would like to study and introduce myself in clustering and high availability for Centos, currently I have not experience at all about it. I would like to ask about the newest method to achieve high availability , load balancing on linux / Centos. So far I have seen the Clustering docs writen for Centos 5 and the HA documentation from www.linux-ha.org that have been published in 2010. So, I would like to ask to comunity, which are the new methods for clustering and get HA and where to get updated documentation. Regards, Leandro.

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filesystem mounting fails at boot
by Imre Gergely 10 Oct '15

10 Oct '15

Hi I have an IBM blade with internal harddisks, in hardware RAID1. I've installed a CentOS 6 64bit on it, everything works just fine. After the installation, I've presented a vdisk to the blade from an external SAN (an HP EVA4000), connected through FiberChannel. I've partitioned the disk, formatted it and mounted it under /store, then added it to fstab. Everything was fine, until I rebooted. At boot I'm getting the following error for /store: Mounting local filesystems: mount: special device UUID=2a587e95-4a6c-4336-bb8b-f0d066905bc5 does not exist It just goes on to boot without mounting this filesystem. After it boots, I can log in and give the command "mount -a", and it gets mounted without problems. As far as I can tell, the reason for this is that CentOS doesn't wait for the external disk to get initialized fully and it just doesn't find it at boot time. I have other CentOS blades, installed and booting from the same SAN and they work without problems, but I noticed that they wait a little bit longer at boot. Am I missing some stuff from initrd? What can I do to make it wait for the block device a bit longer before it tries mounting it ? Thanks! -- Imre Gergely http://havaz.net gpg --keyserver subkeys.pgp.net --recv-keys 0x34525305

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CentOS 7 CUPS: where queue defaults are stored?
by Valeri Galtsev 10 Oct '15

10 Oct '15

Dear Experts, CentOS 7 outsmarted me (again...). Could someone tell me where cups print queues' default settings are stored? In the past I was doing rather trivial thing: I was setting up prototype machine (making kickstart file based on it), then I was configuring all printers on prototype machine. After which (with cups daemon stopped) I was just packing /etc/cups (and maybe /usr/share/cups/model if extra ppd's were added). Then as a post-install I was just moving /etc/cups off the way, and unpacking /etc/cups, and all my printer configuration was there on newly built machine. Not anymore! After done what is described above I indeed have all printers, but queue defaults a weird: "double sided short edge" instead of "double sided long edge" as was configured on the prototype machine. What is more setting off is: recursive grep of /etc does not reveal files containing these settings (OK, OK, I know, I'm stupid, I don't know what pattern to grep for, but they are definitely not in /etc/cups AFAIK, or at leas not as ASCII...). Any insight into the system with - *cough* *cough* - binary configuration files? Incidentally, how do _you_ replicate CUPS configuration on CentOS 7 ? Thanks a lot for your help ! 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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vino-server on Centos 6.7
by Milton Plasencia 09 Oct '15

09 Oct '15

Hi, The vino-server take too much cpu and memory, how to fix it? Cheers, M.

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CentOS-6 SSHD chroot SELinux problem
by James B. Byrne 09 Oct '15

09 Oct '15

I run a sshd host solely to allow employees to tunnel secure connections to our internal hosts. Some of which do not support encrypted protocols. These connections are chroot'ed via the following in /etc/ssh/sshd_config Match Group !wheel,!xxxxxx,yyyyy AllowTcpForwarding yes ChrootDirectory /home/yyyyy X11Forwarding yes Where external users belong to group yyyyy (primary). We have a problem with SELinux in that chrooted users cannot tunnel https requests unless SELinux is set to permissive (or turned off altogether). This problem does not evidence itself unless the account is chrooted. The output from audit2allow is this: sudo audit2allow -l -a #============= chroot_user_t ============== allow chroot_user_t cyphesis_port_t:tcp_socket name_connect; allow chroot_user_t user_home_t:chr_file open; #============= syslogd_t ============== #!!!! The source type 'syslogd_t' can write to a 'dir' of the following types: # var_log_t, var_run_t, syslogd_tmp_t, syslogd_var_lib_t, syslogd_var_run_t, innd_log_t, device_t, tmp_t, logfile, cluster_var_lib_t, cluster_var_run_t, root_t, krb5_host_rcache_t, cluster_conf_t, tmp_t allow syslogd_t user_home_t:dir write; My questions are: Do SE booleans settings exist that permit chrooted ssh access to forward https and log the activity? If so then what are they? If not, then have I made a configuration error in sshd_config? What is it? If not, then is this a defect in the SELinux policy? If not, then What are the implications of creating a custom policy to handle this using the output given above? -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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