Discuss

discuss@lists.centos.org

34753 discussions

Mysql 5.6, Centos 7 and errno: 24 - Too many open files
by Götz Reinicke - IT Koordinator 05 May '15

05 May '15

Hi, may be somewon has a working solution and information on that: I installed the most recent mysql community on a server and do get a lot of "errno: 24 - Too many open files". There are suggestions to increase the open_files_limit, change/add that to /etc/security/limits.conf and modify the systemd script by hand. Depending on how you start mysql (restart, or at systemboot time ...) the limit get set or not. Question: Is that may be a known bug or something? And thats mit a question regarding mariadb or mysql. Regards . Götz -- Götz Reinicke IT-Koordinator Tel. +49 7141 969 82 420 E-Mail goetz.reinicke(a)filmakademie.de Filmakademie Baden-Württemberg GmbH Akademiehof 10 71638 Ludwigsburg www.filmakademie.de Eintragung Amtsgericht Stuttgart HRB 205016 Vorsitzender des Aufsichtsrats: Jürgen Walter MdL Staatssekretär im Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg Geschäftsführer: Prof. Thomas Schadt

6 8

syncookies.c
by Ibrahim Celikbilek 05 May '15

05 May '15

Default,syncookies are activate when syn list(backlog queue) is full. I want hybrid system. I propose a system , syncookies active dynamic per connection . where will I write code , where syncookies system does call in the code file.

2 1

Re: [CentOS] nfs (or tcp or scheduler) changes between centos 5 and 6?
by Peter van Hooft 04 May '15

04 May '15

> Message: 4 > Date: Wed, 29 Apr 2015 08:35:29 -0500 > From: Matt Garman <matthew.garman(a)gmail.com> > To: CentOS mailing list <centos(a)centos.org> > Subject: [CentOS] nfs (or tcp or scheduler) changes between centos 5 > and 6? > Message-ID: > <CAJvUf-CyTg8ZiGq3OXRLKw7s1K2dGx1gqo_2XwOAXXQty=RHZQ(a)mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > We have a "compute cluster" of about 100 machines that do a read-only > NFS mount to a big NAS filer (a NetApp FAS6280). The jobs running on > these boxes are analysis/simulation jobs that constantly read data off > the NAS. > > We recently upgraded all these machines from CentOS 5.7 to CentOS 6.5. > We did a "piecemeal" upgrade, usually upgrading five or so machines at > a time, every few days. We noticed improved performance on the CentOS > 6 boxes. But as the number of CentOS 6 boxes increased, we actually > saw performance on the CentOS 5 boxes decrease. By the time we had > only a few CentOS 5 boxes left, they were performing so badly as to be > effectively worthless. > > What we observed in parallel to this upgrade process was that the read > latency on our NetApp device skyrocketed. This in turn caused all > compute jobs to actually run slower, as it seemed to move the > bottleneck from the client servers' OS to the NetApp. This is > somewhat counter-intuitive: CentOS 6 performs faster, but actually > results in net performance loss because it creates a bottleneck on our > centralized storage. > > All indications are that CentOS 6 seems to be much more "aggressive" > in how it does NFS reads. And likewise, CentOS 5 was very "polite", > to the point that it basically got starved out by the introduction of > the 6.5 boxes. > > What I'm looking for is a "deep dive" list of changes to the NFS > implementation between CentOS 5 and CentOS 6. Or maybe this is due to > a change in the TCP stack? Or maybe the scheduler? We've tried a lot > of sysctl tcp tunings, various nfs mount options, anything that's > obviously different between 5 and 6... But so far we've been unable to > find the "smoking gun" that causes the obvious behavior change between > the two OS versions. > > Just hoping that maybe someone else out there has seen something like > this, or can point me to some detailed documentation that might clue > me in on what to look for next. > > Thanks! > You may want to try reducing sunrpc.tcp_max_slot_table_entries . In CentOS 5 the number of slots is fixed: sunrpc.tcp_slot_table_entries = 16 In CentOS 6, this number is dynamic with a maximum of sunrpc.tcp_max_slot_table_entries which by default has a value of 65536. We put that in /etc/sysconfig/modprobe.d/sunrpc.conf: options sunrpc tcp_max_slot_table_entries=128 You can't put this in /etc/sysctl.conf because the sunrpc kernel module is loaded before sysctl -p is done. peter

2 2

Could not complete SSL handshake to Amazon EC2 host
by Tim Dunphy 04 May '15

04 May '15

Hello, I am trying to monitor a host in the Amazon EC2 cloud. Yet when I try to check NRPE from the monitoring host I am getting an SSL handshake error: [root@monitor1:~] #/usr/local/nagios/libexec/check_nrpe -H ops.jokefire.com CHECK_NRPE: Error - Could not complete SSL handshake. And if I telnet into the host on port 5666 to see if the FW port is open, the connection closes right away: [root@monitor1:~] #telnet ops.somewhere.com 5666 Trying 54.225.218.125... Connected to ops.somewhere.com. Escape character is '^]'. Connection closed by foreign host. You can see there it connects, but then it closes immediately after the connection. I have NRPE running on the host I want to monitor: [root@ops:~] #lsof -i :5666 COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME xinetd 1434 root 5u IPv4 4063 TCP *:nrpe (LISTEN) And I have the IP of my nagios server listed in the xinetd conf file: [root@ops:~] #cat /etc/xinetd.d/nrpe # default: on # description: NRPE (Nagios Remote Plugin Executor) service nrpe { flags = REUSE socket_type = stream port = 5666 wait = no user = nagios group = nagios server = /usr/local/nagios/bin/nrpe server_args = -c /usr/local/nagios/etc/nrpe.cfg --inetd log_on_failure += USERID disable = no only_from = 127.0.0.1 xx.xx.xx.xx # <- representing my real nagios server IP } And I have my default security group for that host open on port 5666 to the world for this experiment. I plan on locking that down again to the single IP of my monitoring host once I get this resolved. Does anyone have any suggestions on how I can get that problem solved? Thanks, Tim -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

6 18

can't disable tcp6 on centos 7
by Tim Dunphy 04 May '15

04 May '15

hey all, I tried disabling tcp v6 on a C7 box this way: [root@puppet:~] #cat /etc/sysctl.conf # System default settings live in /usr/lib/sysctl.d/00-system.conf. # To override those settings, enter new settings here, or in an /etc/sysctl.d/<name>.conf file # # For more information, see sysctl.conf(5) and sysctl.d(5). net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 Then going: [root@puppet:~] #sysctl -p net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 Then I restarted xinetd for good measure: [root@puppet:~] #systemctl restart xinetd [root@puppet:~] # Because I'm trying to hit nrpe on this host. Yet, xinetd/nrpe still seems to be listeing on TCP v6!! [root@puppet:~] #netstat -tulpn | grep -i listen | grep xinetd tcp6 0 0 :::5666 :::* LISTEN 2915/xinetd This is a CentOS 7.1 box: [root@puppet:~] #cat /etc/redhat-release CentOS Linux release 7.1.1503 (Core) What am I doing wrong? I need to be able to disable tcpv6 completely! Thanks Tim -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

7 12

VPN connection before login
by Tim 04 May '15

04 May '15

Hi all, is there a possibility to connect to a VPN manually before login on CentOS desktop (Gnome). I know of a similar functionality in Windows. Is there a tutorial or something? Thank you Tim

6 8

Kvm + libvirt + virt-manager
by Alessandro Baggi 04 May '15

04 May '15

Hi list, I have updated C7 to 7.1 and get some issue (I don't know if problems depend from upgrade). My first problem is on virt-manager that crash after some time. From system messages I get that virt-manager is crashed with signal sigsegv and this problem is related to python (python get sigsegv). Anyone get similar behaviour after upgrade? Another problem, I can't say if it showed before/after upgrade, is related to libvirt when I shutdown my system. On my host I have different vm runned on KVM, where only 2 have autostart enabled. When shutting down the system I get from the console an error like this: Suspending test1: Done Suspending test2: ... error: Failed to save domain $someid state error: internal error: unable to execute QEMU command 'migrate': State blocked by non-migratable device '0000:00:04.8/ich9_ahci' Vm test2 has a disk attached as raw device and not as image file. This message, with same error, is showed also for 2 other vm with autostart disabled and disk on qcow2 images, but only when them are online during shutdown. When system starts, all vms are running without problem. I can't figure out with this error... Why libvirt-guest.sh run migrate command when I shutdown the system? Hope in help. Thanks in advance

3 2

Re: [CentOS] Could not complete SSL handshake to Amazon EC2 host
by Tim Dunphy 04 May '15

04 May '15

> > Not just /var/log/messages. Doesn't nrpe have a log file? Maybe even > secure. Hmmm I don't find any log specific to nrpe. In other words I don't see /var/log/nrpe.log or whatever. :) And when I tail -f /var/log/secure or /var/log/messages I don't see any entries turning up in them when I hit the client with check_nrpe. I was checking the logs on the client itself. > > >> Also nrpe needs to be told from where connections are allowed whether > >> running under an inetd or self-daemonized. > > > >Yep! I've set the only_from to have only the loopback address and the IP > >for the monitoring host in /etc/xinetd.d/npre. > > Not the xinetd config, the nrpe config (too). Hmmmm. but the nrpe.confg file is ignored in the case of allowed hosts. >From the nrpe config: # NOTE: This option is ignored if NRPE is running under either inetd or xinetd allowed_hosts=127.0.0.1 Thanks for the input tho, I genuinely appreciate it! On Sat, May 2, 2015 at 4:05 PM, Mark Milhollan <mlm(a)pixelgate.net> wrote: > On Sat, 2 May 2015, Tim Dunphy wrote: > > >>>It's only when checking from the monitoring host that nrpe fails: > >>Check /var/log/messages to see if xinetd says anything. > > > >I tailed /var/log/messages while hitting the client with check_nrpe from > >the monitoring host. However, that didn't cause an entry in the messages > >log. > > Not just /var/log/messages. Doesn't nrpe have a log file? Maybe even > secure. > > >> Also nrpe needs to be told from where connections are allowed whether > >> running under an inetd or self-daemonized. > > > >Yep! I've set the only_from to have only the loopback address and the IP > >for the monitoring host in /etc/xinetd.d/npre. > > Not the xinetd config, the nrpe config (too). > > > /mark > -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

3 2

Re: [CentOS] Could not complete SSL handshake to Amazon EC2 host
by Tim Dunphy 02 May '15

02 May '15

> > >And I made sure the local firewall was stopped, because I am blocking > ports > >with the security groups instead. > As an aside, I wouldn't do this unless running in a VPC as there are > other hosts in the general cloud and many are malicious. Hmmm... you make an excellent point! I picked up this habit from an AWS shop I used to work at. But what you just said will make me reconsider! > > >It's only when checking from the monitoring host that nrpe fails: > Check /var/log/messages to see if xinetd says anything. I tailed /var/log/messages while hitting the client with check_nrpe from the monitoring host. However, that didn't cause an entry in the messages log. > Also nrpe needs > to be told from where connections are allowed whether running under an > inetd or self-daemonized. Yep! I've set the only_from to have only the loopback address and the IP for the monitoring host in /etc/xinetd.d/npre. > > Also check the NRPE reviews on exchange.nagios.org, where the issue is > discussed. Cool! Thanks. I'll check it out, and see if I can find anything useful. I appreciate the input! Also I really appreciate the ongoing dialog with the community on this issue. I'm grasping at straws at this point. And all the attempts at help have been really great! I hope we can still get to the bottom of this! Tim On Sat, May 2, 2015 at 11:45 AM, Mark Milhollan <mlm(a)pixelgate.net> wrote: > On Fri, 1 May 2015, Tim Dunphy wrote: > > >And I made sure the local firewall was stopped, because I am blocking > ports > >with the security groups instead. > > As an aside, I wouldn't do this unless running in a VPC as there are > other hosts in the general cloud and many are malicious. > > >It's only when checking from the monitoring host that nrpe fails: > > Check /var/log/messages to see if xinetd says anything. Also nrpe needs > to be told from where connections are allowed whether running under an > inetd or self-daemonized. > > Also check the NRPE reviews on exchange.nagios.org, where the issue is > discussed. > > > /mark > -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

1 0

Re: [CentOS] Folding At Home OT
by Mark LaPierre 02 May '15

02 May '15

On 04/22/15 21:05, Mark LaPierre wrote: > Can someone recommend a good video card to use with CentOS 6.6 that has > a GPU, or two, or more, that will work with the Folding At Home project. > > I built a killer machine primarily for contributing to the FAH effort > but the video card, NVIDIA Corporation G94 [GeForce 9600 GT], I had on > hand is not getting any assignments. I'm using the proprietary NVIDIA > driver. I've got a pcie 16X socket to plug it into. > The underwelming response to my question leaves me wondering: Am I to gather that there are no CentOS FAH users here? or Am I to understand that none of the CentOS FAH users have a GPU that works with FAH? -- _ °v° /(_)\ ^ ^ Mark LaPierre Registered Linux user No #267004 https://linuxcounter.net/ ****

4 5

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Discuss