Discuss September 2012

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139 participants
148 discussions

hi
by Andrei Rolando León Salas 28 Sep '12

28 Sep '12

Hello how are u, im having a little problem. i use the webmin to install automatly postfix, in the other server works, but in this now says. Error while checking current Postfix configuration. Please manually fix Postfix configuration. postfix: fatal: file /etc/postfix/main.cf: parameter mail_owner: unknown user name value: postfix Manually edit the Postfix configuration file.<https://mercadeoeficaz-cr.com:10000/postfix/edit_manual.cgi> i dont know what to do, can u help me please

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Apache : Listen on ports other than 80
by adekunleadekoya＠gmail.com 28 Sep '12

28 Sep '12

Sent from my BlackBerry wireless device from MTN -----Original Message----- From: adekunleadekoya(a)gmail.com Date: Fri, 28 Sep 2012 18:49:33 To: <CentOS(a)mailing.list> Reply-To: adekunleadekoya(a)gmail.com Subject: Apache : Listen on ports other than 80 Hi, I just install centos 6.3 on my oracle virtualbox. I tried 2 configure apache 2 listen on port say 1010 but after adding a 'Listen 1010' to the httpd.conf file and then try 2 restart d httpd service, I found that d service failed to start. If I remove the 'Listen 1010' line then d httpd service restarts successfully. What do I need to do so I could instruct d web server to use other ports (besides 80) ? Are there default settings in centos that are causing this prob ? I have done same experiment successfully wit apache on windows. I need to setup virtualhost with my apache on centos. I need help now. Pls help! Regards Kunle Sent from my BlackBerry wireless device from MTN

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OT: forwarding SNMP traps
by James Pifer 28 Sep '12

28 Sep '12

Can anyone here give me a hand with forwarding snmp traps? I'm looking at Zenoss and I want to see how it handles snmp traps. We currently have snmp traps getting sent to two servers. One of them is basically ignoring the traps, but I can't just change the ip address (to give to Zenoss) because of other things the host is doing. So instead I'd like to simply forward the snmp traps to the new zenoss system. I've tried a couple different forwarding programs, like jredirect and a python script I found while searching. I use jredirect to forward some other things, but I'm guessing it doesn't like udp. I've also tried figuring out snmptrapd and snmpd without any success at all. Last, I tried simply using iptables with something like: # iptables -t nat -A PREROUTING -i eth0 -p udp -m udp --dport 162 -j DNAT --to-destination 192.168.1.3:162 # iptables -A INPUT -i eth0 -p udp -m udp --dport 162 -j ACCEPT But that doesn't seem to work either. I can see running wireshark on both systems that the old server is receiving traps, but they are never getting forwarded to the zenoss system. Anyone here know how to do it? Any assistance is appreciated. Thanks, James

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netcat issue: no UDP transmission
by Boris Epstein 28 Sep '12

28 Sep '12

Hello listamtes, Here's is a curious issue: netcat (nc) seems to not do UDP for me, even though TCP works flawlessly. Not even on the local host. Here's the "server session" I am running: cat test.dd | nc -l -u -n -k -v 2456 (test.dd is just a large file with random data) Here's the client: nc -v -u 127.0.0.1 2456 | dd of=/dev/null ^C0+0 records in 0+0 records out 0 bytes (0 B) copied, 219.944 s, 0.0 kB/s Here's what netstat reports: netstat -a -n | grep 2456 udp 0 0 0.0.0.0:2456 0.0.0.0:* udp 0 0 127.0.0.1:52394 127.0.0.1:2456 ESTABLISHED unix 3 [ ] STREAM CONNECTED 12456 So the connection is established - but no data appears to be getting transferred. This behaviour seems to be the same on CentOS 6 and LinuxMint. Any idea what may be going on? Thanks. Boris.

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Re: [CentOS] High memory needs [SOLVED]
by Jérémie Dubois-Lacoste 28 Sep '12

28 Sep '12

I finally found a solution to our problem. I think some people running like us a combination CentOS 64 bits\Sun Grid Engine, could encounter the same situation. Here is a detailed explanation, hope it can be useful to someone! The file /usr/lib/locale/locale-archive is a memory-mapped file used by glibc (the gnu C library). This file contains the languages used over the system (for instance, man pages). This memory-mapping allows to read in the file as if it were in memory, avoiding system calls used to perform disk-read operations, therefore it allows much faster access. Memory-mapped files (as well as shared libraries) are counted as part of the virtual memory of processes (see "top" command, "VIRT" field). Therefore, the part of the locale-archive file mapped to memory adds up to the virtual memory of every processes that makes use of glibc (basically everything), while this is actually only once in memory. In other words, for every processes, the virtual memory overestimates the real memory of the process by, at least, the part of the locale-archive file which is memory-mapped. Apparently, on 32bits distros, and on most 64bits distros, only a part of the locale-archive file is mmapped: for instance on CentOS 32 bits: $ pmap $$ b7689000 2048K r---- /usr/lib/locale/locale-archive Only 2MB of the file are mmapped, while the file is actually ~54MB. Some distros only install a small subsets of languages, for instance on my Ubuntu 12.04, this file is only ~3MB. I still don't get the reason, but CentOS x86_64 6.2 (and 6.3) mmappes the *entire* file: $ pmap $$ 00007f217fae4000 96836K r---- /usr/lib/locale/locale-archive Consequence: every processes that use glibc is overestimated by ~100MB (according to the virtual memory). That, alone, is not a problem at all. It is known that the virtual memory is a bad estimation of the actual memory used, the fact that it is largely overestimated does not matter much in most cases. The problem, however, is that if you deal with a computing cluster that uses Sun Grid Engine (we have version 6.2u5) it uses this value to check whether jobs exceed their memory limit or not. The consequence is a false impression that jobs require a huge amount of memory, SGE being miss-leaded, and thus killing them. A solution could be to restrict the number of languages when installing glibc-common (which provides the locale-archive file), to have a smaller locale-archive file. This should be possible with: $ echo "%_install_langs <lang1>:<lang2>:<lang3>" >> /etc/rpm/macros.lang $ rpm -e glibc-common --nodeps $ rm /usr/lib/locale/locale-archive $ rpm -i <glibc-common.rpm> I don't know why but we couldn't have glibc-common (2.12-1.80) taking it into account, though. All languages were always installed. I read somewhere that it is done on purpose, not sure... The solution that worked for us is a post-install fix that consists of removing all languages that we don't use. We checked with "locale" which languages are used on the system. Then we remove all the others: $ localedef --list-archive | grep -v -e "en_US" -e "de_DE" -e "en_GB" | xargs localedef --delete-from-archive $ mv /usr/lib/locale/locale-archive /usr/lib/locale/locale-archive.tmpl $ build-locale-archive After this, the size of the locale-archive file is ~4MB, and running a single Bash instance does not show "107MB" for SGE anymore :-) Et voilà! Jérémie 2012/9/27 Les Mikesell <lesmikesell(a)gmail.com>: > On Thu, Sep 27, 2012 at 10:46 AM, Gordon Messmer <yinyang(a)eburg.com> wrote: >> >>> I understand it may not be very precise, however I still don't >>> understant the difference compared to other x64 ditributions, >>> under CentOS the value is 7 times higher! > > This might explain it: > https://bugzilla.redhat.com/show_bug.cgi?id=156477 > The mmapped local-archive contains all languages even though only the > ones you use are accessed from it. Other distros split them and the > installers only install what you want. > >> 64 bit system: >> 00007f8ae84b7000 102580K r---- /usr/lib/locale/locale-archive >> >> 32 bit: >> b7689000 2048K r---- /usr/lib/locale/locale-archive > > That's an interesting difference on its own, since the underlying > files are about 95M and 54M respectively. Does the 32 bit kernel use > some tricks to sparsely map files where the 64 bit one does it > directly with page tables? > > -- > Les Mikesell > lesmikesell(a)gmail.com > _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > http://lists.centos.org/mailman/listinfo/centos

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Re: [CentOS] Routing issue
by Manish Kathuria 28 Sep '12

28 Sep '12

On Thu, Sep 27, 2012 at 8:55 PM, Steve Clark <sclark(a)netwolves.com> wrote: > On 09/27/2012 11:01 AM, Manish Kathuria wrote: > > On Thu, Sep 27, 2012 at 7:04 PM, Steve Clark <sclark(a)netwolves.com> wrote: > > On 09/26/2012 11:57 PM, Manish Kathuria wrote: > > On Thu, Sep 27, 2012 at 7:46 AM, Gordon Messmer <yinyang(a)eburg.com> wrote: > > On 09/26/2012 09:15 AM, Steve Clark wrote: > > The routes-x.y-z.diff is a unified patch containing different parts > which include support for Dead Gateway Detection as well. However, > since that is limited to the first hop, it is preferable to have a > userspace script as you are doing. I also use a script to check the > accessibility of a remote popular site from each of the ISPs and based > upon the response the links are treated alive or dead and the default > gateway is changed. However, the routing problem as described by you > will only be solved after applying this patch (routes-x.y-z.diff). > > As for marking the incoming packets to ensure that they go out from > the same interface they came from, you could do something like the > following: > > Using iptables mark the incoming traffic from external interfaces > > /sbin/iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark > /sbin/iptables -t mangle -A OUTPUT -j CONNMARK --restore-mark > /sbin/iptables -t mangle -A PREROUTING -i eth1 -j MARK --set-mark 1 > /sbin/iptables -t mangle -A PREROUTING -i eth1 -j CONNMARK --save-mark > /sbin/iptables -t mangle -A PREROUTING -i eth2 -j MARK --set-mark 2 > /sbin/iptables -t mangle -A PREROUTING -i eth2 -j CONNMARK --save-mark > > Add the following rules to your existing ones for policy routing > > /sbin/ip rule add fwmark 1 table T1 > /sbin/ip rule add fwmark 2 table T2 > > Hi Manish, > > Thanks for the info. The one question I have is about > /sbin/iptables -t mangle -A OUTPUT -j CONNMARK --restore-mark > > I thought the OUTPUT chain was only for packets originating locally. I am > only concerned > with clients behind my Linux router, do I still need this? Yes you are right but in case if you have any services running on the linux router itself (for example sshd) and accessible from the internet, it would help. > > Again, thanks much for responding. > > -- > Stephen Clark > NetWolves > Director of Technology > Phone: 813-579-3200 > Fax: 813-882-0209 > Email: steve.clark(a)netwolves.com > http://www.netwolves.com

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rpm archives
by Kaushal Shriyan 28 Sep '12

28 Sep '12

Hi Is there a way to retrieve old rpm binaries from archives. Regards Kaushal

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Re: [CentOS] Routing issue
by Manish Kathuria 27 Sep '12

27 Sep '12

On Thu, Sep 27, 2012 at 7:04 PM, Steve Clark <sclark(a)netwolves.com> wrote: > On 09/26/2012 11:57 PM, Manish Kathuria wrote: > > On Thu, Sep 27, 2012 at 7:46 AM, Gordon Messmer <yinyang(a)eburg.com> wrote: > > On 09/26/2012 09:15 AM, Steve Clark wrote: > > Is there a way to make this work correctly? > > In addition, you should ideally applying the following patches for > Static, Alternative Routes, Dead Gateway Detection & NAT and recompile > the kernel: > > http://www.ssi.bg/~ja/#routes > > > Hmmm... not being a kernel guru, correct me if I am wrong but isn't the > route patch used to detect dead nexthops? > I am already doing that from userspace. > > The second set looks like is calls the routing logic after the SNAT, is that > correct? This could solve the problem. > Why aren't these patches in the kernel? > > Thanks, > The routes-x.y-z.diff is a unified patch containing different parts which include support for Dead Gateway Detection as well. However, since that is limited to the first hop, it is preferable to have a userspace script as you are doing. I also use a script to check the accessibility of a remote popular site from each of the ISPs and based upon the response the links are treated alive or dead and the default gateway is changed. However, the routing problem as described by you will only be solved after applying this patch (routes-x.y-z.diff). As for marking the incoming packets to ensure that they go out from the same interface they came from, you could do something like the following: Using iptables mark the incoming traffic from external interfaces /sbin/iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark /sbin/iptables -t mangle -A OUTPUT -j CONNMARK --restore-mark /sbin/iptables -t mangle -A PREROUTING -i eth1 -j MARK --set-mark 1 /sbin/iptables -t mangle -A PREROUTING -i eth1 -j CONNMARK --save-mark /sbin/iptables -t mangle -A PREROUTING -i eth2 -j MARK --set-mark 2 /sbin/iptables -t mangle -A PREROUTING -i eth2 -j CONNMARK --save-mark Add the following rules to your existing ones for policy routing /sbin/ip rule add fwmark 1 table T1 /sbin/ip rule add fwmark 2 table T2 Thanks, -- Manish Kathuria

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rename network card device /dev/p3p2 to /dev/eth0
by KNOPS Manfred 27 Sep '12

27 Sep '12

Hello, My name is Manfred. I have to install a flexlm license server on a pc with centos 6.3 as operating system. This machine contains two network cards. An Ethernet card and a wifi card. For the Ethernet card centos generates a device called p3p2. For the wifi card centos generates a device called wlan0. In this configuration the flexlm license program called lmgrd only got the mac address of wlan0. The vendor daemon got no mac address as host ID. Yesterday I made one test. Therefore I edited /etc/udev/rules.d/70-peristant-net.rules. This file contains only one line. This line defines how to name the device for the wifi card. I changed the name Option from name="wlan0" to name="eth0". After rebooting centos generates a device called /dev/et0. Both lmgrd and vendor daemon found the host ID. But lmgrd and safetech can't communicate together. As next I will try to rename /dev/p3p2 which is the device for the Ethernet card. I guess, if I can generate a device called /dev/eth0 for the Ethernet card the license server should work. But in /etc/udev/rules.d/70-persitant-net.rules is no rule for this device. How can I configure centos to generate /dev/eth0 for the Ethernet card? Mit freundlichen Grüßen / Best Regards / Cordialement, Manfred This email and any attachments are intended solely for the use of the individual or entity to whom it is addressed and may be confidential and/or privileged. If you are not one of the named recipients or have received this email in error, (i) you should not read, disclose, or copy it, (ii) please notify sender of your receipt by reply email and delete this email and all attachments, (iii) Dassault Systemes does not accept or assume any liability or responsibility for any use of or reliance on this email. For other languages, go to http://www.3ds.com/terms/email-disclaimer

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BackupPC and rsync
by Emmett Culley 27 Sep '12

27 Sep '12

I have been using BackupPC via rsync daemons on the target machines and all has been working well. At least until about the time rsync went to version 3.0.6. Since then backups have been failing for some targets. The failure is a TCP ZeroWindow issue. It looks like the server rsync process cannot empty it's buffer soon enough and eventually the process fails. I really do not know if it is rsync version related, because I never looked at the packet stream until I started having failures. BackupPC was running on a VM host and the failing machine was one of the guest VMs. I tried upgrading rsync to 3.0.9 and that didn't help. So I moved the BackupPC set up to a different server (no VM). Not all backups are working. though I still see some ZeroWindow packets along with a few retransmision packets. But the backup completes on all machines, including the VM that was failing before. I've googled rsync zerowindow and found some references, but none seemed to apply to my situation. Anybody else having a similar experience? Emmett

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Discuss September 2012