Vnx-rootfscentos

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Revision as of 20:13, 20 May 2012 by David (talk | contribs) (Installing additional software)
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How to create a CentOS root filesystem for VNX

(being updated...do not use)

Basic installation

Follow this procedure to create a CentOS based root filesystem for VNX. The procedure has been tested with CentOS 6.2.

  • Create the filesystem disk image:
  • qemu-img create -f qcow2 vnx_rootfs_kvm_centos.qcow2 8GB
    
  • Get CentOS installation DVD (we recommend to use the complete DVD; the LiveDVD version does not include the customization menu to choose among different installation profiles: minimal, desktop, etc). For example:
  • wget ftp://ftp.rediris.es/mirror/CentOS/6.2/isos/i386/CentOS-6.2-i386-bin-DVD1.iso
    cp CentOS-6.2-i386-bin-DVD1.iso /almacen/iso
    

    Note: latests versions of CentOS are distributed in two DVDs. However, only the first DVD is needed for basic installations; no need to download DVD2.

  • Create the virtual machine with:
  • vnx --create-rootfs vnx_rootfs_kvm_centos.qcow2 --install-cdrom /almacen/iso/CentOS-6.2-i386-bin-DVD1.iso --mem 768M
    

    Note: around 768M of memory are needed to use the graphical installation assistant. With the textual assistant the memory requirements are lower (known to work with 512M).

  • Follow the CentOS installation assistant. At some point, you will have to choose among different system profiles: Desktop, Minimal Desktop, Minimal, Basic Server, etc.
  • Once the installation is finished (the system will have to be rebooted to carry out the final steps), configure the serial console following these instructions.
  • Finally, delete the net udev rules file, halt the system and restart it with the following command:
  • rm /etc/udev/rules.d/70-persistent-net.rules
    vnx --modify-rootfs vnx_rootfs_kvm_centos-6.2-v024.qcow2 --update-aced
    

    Note: ignore the errors "timeout waiting for response on VM socket".

    Configuration

    • Access the system through the text console to easy the copy-paste of commands:
    • virsh console vnx_rootfs_kvm_centos.qcow2
      
    • Check that you have network connectivity. Maybe you have to activate the network interface by hand:
    • dhclient eth1
      

      Note: use "ip link show" to know which network interface to use.

    • Configure the RPMForge repository following the procedure described here:
    • yum install wget
      wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.i686.rpm
      rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt
      rpm -K rpmforge-release-0.5.2-2.el6.rf.*.rpm
      rpm -i rpmforge-release-0.5.2-2.el6.rf.*.rpm
      
    • Update the system and install additional packages
    • yum update
      yum install perl perl-XML-DOM perl-XML-Parser acpid daemonize
      
    • Install VNX autoconfiguration daemon:
    • mount /dev/sdb /mnt/
      perl /mnt/vnxaced-lf/install_vnxaced
      
    • Disable the services you are not going to use (you can see the list of active services with "chkconfig --list"). For example to disable sendmail and bluetooth:
    • chkconfig sendmail off
      chkconfig bluetooth off
      
    • Disable eth0 autoconfiguration to avoid delays at startup. Edit /etc/sysconfig/network-scripts/ifcfg-eth0 file and change "ONBOOT" line to:
    • ONBOOT=no
      
    • Optionally:
      • Disable the firewall. Firewall is enabled by default which could be problematic for testing purpose systems. If desired, disable it using the following command:
      • chkconfig iptables off
        chkconfig ip6tables off
        
      • Enable IPv6 by deleting the following lines in /etc/modprobe.conf:
      • alias ipv6 off
        options ipv6 disable=1
        
    • Create a file /etc/vnx_rootfs_version to store version number and informacion about modifications:
    • VER=v0.24
      OS=CentOS 6.2
      DESC=Basic CentOS 6.2 root-filesystem without GUI
      
    • Stop the machine with that script:
    • vnx_halt
      

    Installing additional software

    To install additional software or to modify your root file system, you just have to:

    • Start a virtual machine from it:
    • vnx --modify-rootfs vnx_rootfs_kvm_centos-6.2-v024.qcow2
      
    • Check network connectivity. Maybe you have to activate the network interface by hand:
    • dhclient eth1
      

      Note: use "ip link show" to know which network interface to use.

    • Install or modify what you want.
    • Finally, halt the system using:
    • vnx_halt
      

      vnx_halt deletes some caches and log files and lets you write a short message describing the modifications done which is saved in /etc/vnx_rootfs_version file

    Updating VNXACED

    vnx --modify-rootfs vnx_rootfs_kvm_centos-6.2-v024.qcow2 --update-aced -y
    

    Known issues

    • When executing commands using vnx "--exe" option, traces like the followinf appear on the consoles:
    • hdb: tray open
      end_request: I/O error, dev hdb, sector 8388352
      

      They are generated as a result of mount command execution by the VNX daemon. Commands are correctly executed. To be further investigated.