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34758 discussions

iSCSI / GFS shared web server file system
by jchase 27 Apr '10

27 Apr '10

We currently have a MD3000i with an iSCSI LUN shared out to our apache web server. We are going to add another apache web server into the mix using LVS to load balance, however, I am curious how well iSCSI handles file locking and data integrity. I have the iSCSI partition formatted as ext3. Is my setup totally flawed and will ext3 not allow for data integrity with multiple apache hosts reading/writing to the shared storage? Am I required to also setup GFS across my apache hosts or does iSCSI somehow manage this? Thanks for helping clear this up, James

7 9

Transparent proxy with LVS
by Enrique Verdes 27 Apr '10

27 Apr '10

I've managed to configure a LVS Cluster to act as a transparent proxy squid farm, with a virtual server as load balancer, and three real servers. Because redirecting packets going to port 80 to port 3128 of squid in the load balancer doesn't works, the solution has a mix of ip route and iptables. Here is the script I wrote to configure transparent proxy. #!/bin/bash #Transparent proxy configuration #Variables VIP=192.168.18.10 WEB=80 SRV01=192.168.18.40 SRV02=192.168.18.41 SRV03=192.168.18.42 #Packet marking iptables -t mangle -F iptables -t mangle -A PREROUTING -p tcp --dport $WEB --dst ! $VIP -j MARK --set-mark 2 #Routing table creation if [ $(grep -sq 'www\.out' /etc/iproute2/rt_tables) ]; then echo "Table exists" else echo "202 www.out" >> /etc/iproute2/rt_tables fi #Clean tables and rules ip rule del prio 100 fwmark 2 table www.out ip route flush table www.out #Routing of marked packets ip rule add prio 100 fwmark 2 table www.out ip route add table www.out to local 0/0 dev lo ip route flush cache #ipvsadm rules ipvsadm -A --fwmark-service 2 ipvsadm -a --fwmark-service 2 --real-server $SRV01 --gatewaying ipvsadm -a --fwmark-service 2 --real-server $SRV02 --gatewaying ipvsadm -a --fwmark-service 2 --real-server $SRV03 --gatewaying As you can see, I mark all packets not directed to the virtual server itself, to port 80 with 2, and then route all those marked packets to the loopback interface. With ipvsadm I forward the marked packets to the real servers. In the real servers there's a rule in the prerouting chain to redirect those packets to port 3128 I'm using pulse service to start lvs, and would like to add the ipvsadm rules to the /etc/sysconfig/ha/lvs.cf, so they are issued by pulse at startup. I can't figure out how to do it. When I try to start pulse, it fails because i left the address field empty. But this service is not tied to any address, I just want the fwmark match to forward the packets to the real servers. I also have dns in this lvs cluster. Any suggestion about how I can add my ipvsad rules to the lvs.cf file? -- Enrique Verdes <EVerdes(a)conatel.com.uy> Depto. de Ingeniería - CONATEL S.A. Este mensaje es privado y confidencial y tiene como único destinatario la persona a la que va dirigida. La responsabilidad de su contenido es del remitente y no de CONATEL. Si usted ha recibido este mensaje por error, tenga presente que le está prohibido revelarlo, copiarlo o distribuirlo, debiendo avisar de inmediato al remitente y borrarlo de su sistema. El error de transmisión no implica renuncia a la privacidad y confidencialidad. This email is private and confidential and intended solely for the use of the individual to whom it is addressed. The responsibility of its content is the sender's and not CONATEL'S. If you have received this email by mistake please notify the sender immediately and delete it from your system. Its disclosure, copy or distribution is absolutely forbidden. The transmission error does not imply a waiver of privacy and confidentiality.

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[off-topic] RHEL6 and NIS/YP
by Marcelo M. Garcia 27 Apr '10

27 Apr '10

Hi Did anyone managed to configure RHEL 6 beta to authenticate using NIS? During the installation the option to use NIS as authentication method is disable. When I tried to install with yum, I got the following message: Installed size: 222 k Is this ok [y/N]: y Downloading Packages: ftp://ftp.redhat.com/pub/redhat/rhel/beta/6/i386/os/Packages/yp-tools-2.9-8…: [Errno 14] PYCURL ERROR 6 - "" Trying other mirror. ftp://ftp.redhat.com/pub/redhat/rhel/beta/6/i386/os/Packages/ypbind-1.20.4-…: [Errno 14] PYCURL ERROR 6 - "" Trying other mirror. Error Downloading Packages: 3:ypbind-1.20.4-21.el6.i686: failure: Packages/ypbind-1.20.4-21.el6.i686.rpm from rhel-beta: [Errno 256] No more mirrors to try. yp-tools-2.9-8.1.el6.i686: failure: Packages/yp-tools-2.9-8.1.el6.i686.rpm from rhel-beta: [Errno 256] No more mirrors to try. Thanks Marcelo

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NFS mount problem
by sync 27 Apr '10

27 Apr '10

Hi,guys: I am trying to connect to a NFS-filesystem on a CentOS 5.3 i386 guest system. The host system is CentOS 5.4 x86_64. I set up the NFS server correctly and rpcinfo is also ok inside the guest system show. The problem is, I can't connect to, or see the open port from the outside. I use the Host-Only network setup with VirtualBox 3.1.0, the ip address in the guest system is 192.168.56.101 . and the host system ip address is 192.168.7.67 When I mount the directory from the guest system via NFS, the result is the following : "mount : 192.168.56.101:/xx failed , reason given by server:Permission denied" I hope one of you can give me a hint in which direction I should continue my efforts. Thanks in advance,,,

9 17

Re: [CentOS] System Resources Graphing
by James Hogarth 27 Apr '10

27 Apr '10

Had zabbix at my last place... hated it... Use nagios + pnp4nagios now with sar running for detailed bits with a custom nagios plugin using sar for performance data. Works very nicely :) James On Apr 27, 2010 5:14 AM, "Rajagopal Swaminathan" <raju.rajsand(a)gmail.com> wrote: Greetings, On Mon, Apr 26, 2010 at 9:39 PM, Matt <lm7812(a)gmail.com> wrote: > Is there a package I can get that... Try Zabbix. It may be seem to be an overkill. All the same, it is very extensible and have tried it in couple of scenarios of remote and local monitoring of diverse devices and processes. and oh SVN checkout may be a good bet. There are, of course, rpms are CentOS are available in a repo (AndrewFarley) Available HTH, Regards, Rajagopal _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.c...

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Help with NFSV4 server
by Clint Dilks 27 Apr '10

27 Apr '10

Hi Everyone, I have been trying to setup an NFS v4 File Server but have come across an odd issue. Mounting the /nfs4exports/share appears to be successful and the information displayed about partition size and free space seem correct but if I try to do anything inside the mounted directory the client will just hang. Does anyone have any idea what I am missing?? I have try disabling all firewalls and selinux but it doesn't seem to make any difference I have taken a look at http://www.brennan.id.au/19-Network_File_System.html#nfs <http://www.brennan.id.au/19-Network_File_System.html#nfs4>4 <http://www.brennan.id.au/19-Network_File_System.html#nfs4> and http://blog.laimbock.com/2009/05/21/nfsv4-on-centos-53-and-fedora-11/ and still can't see what i'm doing wrong {The Server} CentOS 5.4 64 Bit [root@inf1 /]# cat /etc/exports /nfs4exports *.scms.waikato.ac.nz(rw,insecure,sync,wdelay,no_subtree_check,no_root_squash,fsid=0,nohide) /nfs4exports/share *.scms.waikato.ac.nz(rw,insecure,sync,wdelay,no_subtree_check,no_root_squash,nohide) [root@inf1 /]# cat /etc/sysconfig/nfs # # Define which protocol versions mountd # will advertise. The values are "no" or "yes" # with yes being the default #MOUNTD_NFS_V1="no" MOUNTD_NFS_V2="no" MOUNTD_NFS_V3="no" # # # Path to remote quota server. See rquotad(8) #RQUOTAD="/usr/sbin/rpc.rquotad" # Port rquotad should listen on. #RQUOTAD_PORT=875 # Optinal options passed to rquotad #RPCRQUOTADOPTS="" # # Optional arguments passed to in-kernel lockd #LOCKDARG= # TCP port rpc.lockd should listen on. #LOCKD_TCPPORT=32803 # UDP port rpc.lockd should listen on. #LOCKD_UDPPORT=32769 # # # Optional arguments passed to rpc.nfsd. See rpc.nfsd(8) # Turn off v2 and v3 protocol support #RPCNFSDARGS="-N 2 -N 3" # Turn off v4 protocol support #RPCNFSDARGS="-N 4" # Number of nfs server processes to be started. # The default is 8. #RPCNFSDCOUNT=8 # Stop the nfsd module from being pre-loaded #NFSD_MODULE="noload" # # # Optional arguments passed to rpc.mountd. See rpc.mountd(8) #RPCMOUNTDOPTS="" # Port rpc.mountd should listen on. #MOUNTD_PORT=892 # # # Optional arguments passed to rpc.statd. See rpc.statd(8) #STATDARG="" # Port rpc.statd should listen on. #STATD_PORT=662 # Outgoing port statd should used. The default is port # is random #STATD_OUTGOING_PORT=2020 # Specify callout program #STATD_HA_CALLOUT="/usr/local/bin/foo" # # # Optional arguments passed to rpc.idmapd. See rpc.idmapd(8) #RPCIDMAPDARGS="" # # Set to turn on Secure NFS mounts. #SECURE_NFS="yes" # Optional arguments passed to rpc.gssd. See rpc.gssd(8) #RPCGSSDARGS="-vvv" # Optional arguments passed to rpc.svcgssd. See rpc.svcgssd(8) #RPCSVCGSSDARGS="-vvv" # Don't load security modules in to the kernel #SECURE_NFS_MODS="noload" # # Don't load sunrpc module. #RPCMTAB="noload" # [root@inf1 /]# cat /etc/idmapd.conf [General] Verbosity = 9 Pipefs-Directory = /var/lib/nfs/rpc_pipefs Domain = scms.waikato.ac.nz [Mapping] Nobody-User = nfsnobody Nobody-Group = nfsnobody [Translation] Method = nsswitch [root@inf1 /]# mount -l | grep bind /export on /nfs4exports/share type none (rw,bind) And an ls of /nfs4exports/share on NFS Server works from /etc/fstab /export /nfs4exports/share none bind 0 0 {The Client} [root@silver ~]# cat /etc/idmapd.conf [General] Verbosity = 0 Pipefs-Directory = /var/lib/nfs/rpc_pipefs Domain = scms.waikato.ac.nz [Mapping] Nobody-User = nfsnobody Nobody-Group = nfsnobody [Translation] Method = nsswitch From /etc/fstab inf1:/ /test nfs4 auto,rw,nodev,sync,_netdev,proto=tcp,retry=10,rsize=32768,wsize=32768,hard,intr 0 0

4 4

FW: System Resources Graphing
by Simon Billis 26 Apr '10

26 Apr '10

Matt sent a missive on 2010-04-26: > Is there a package I can get that will graph system resources such as > CPU and disk I/O to an html file or something? You could use any of these hyperic, cricket depending on your needs and wants... I use/used cacti, ganglia, mrtg and hyperic... ganglia we currently use to gather performance data and replaced hyperic (better fit for us) and we also use cacti for collecting snmp data from switches and routers. I'm considering switching to cricket in place of cacti for performance reasons (only generates graphs when needed).

1 0

URGENT
by cahit Eyigünlü 26 Apr '10

26 Apr '10

I had a geub loader error 2 on starting centos and i am able to connect rescue system this is the result how could i get system work root@rescuecd64 ~ # grub Probing devices to guess BIOS drives. This may take a long time. Unknown partition table signature GNU GRUB version 0.97 (640K lower / 3072K upper memory) [ Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists the possible completions of a device/filename. ] grub> find /boot/grub/stage1 find /boot/grub/stage1 Error 15: File not found grub>

5 5

USB keys
by m.roth＠5-cent.us 26 Apr '10

26 Apr '10

Well, we wanted to put an install on a USB key. Neither I nor the other admin was amused by the singing and dancing that the wiki offers - and just *why* is it that syslinux is broken? At any rate, I did some googling, and found <http://www.pendrivelinux.com/>, and I ran this installer. Ok, it has some bugs: a) I had several .isos, and it *insisted* on grabbing the first one, alphabetically, no matter that I put in the full name. It also takes for-bloody-ever - 4.5 *hours* for the 4G DVD. However, it finished, I stuck it into a laptop, told it to boot from the USB, and there was the begin install screen. *shrug* Looks good to me. I just do not understand why it's such a song and dance, rather than, say, syslinux /dev/sdb1 mount /dev/sdb1 /tmp/mnt mount -o loop CentOS....iso /mnt cp -pr /mnt/ /tmp/mnt mark

4 6

Sendmail problem
by sync 26 Apr '10

26 Apr '10

Hi, guys:

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