Difference between revisions of "Vnx-rootfscentos"

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(Installing additional software)
(Configuration)
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<li>Finally, stop the virtual machine with:</li>
 
<li>Finally, stop the virtual machine with:</li>
 
  vnx_halt
 
  vnx_halt
 +
''vnx_halt'' deletes some caches and log files and optionally lets you write a short message to ''/etc/vnx_rootfs_version file'' describing the latest modifications done.
 
</ul>
 
</ul>
  

Revision as of 15:26, 21 May 2012

How to create a CentOS root filesystem for VNX

Basic installation

Follow this procedure to create a CentOS based root filesystem for VNX. The procedure has been tested with CentOS 6.2 and 5.6.

  • 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-media /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 and halt the system:
  • rm /etc/udev/rules.d/70-persistent-net.rules
    halt
    

Configuration

  • Restart the system with the following command:
  • vnx --modify-rootfs vnx_rootfs_kvm_centos.qcow2 --update-aced --mem 768M
    

    Note: ignore the errors "timeout waiting for response on VM socket". 768M are needed if you are installing a root filesystem with desktop interface

  • 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
    
  • Optionally:
    • Disable the services you are not going to use to speed up the virtual machine startup (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 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
      
  • 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
    
  • Finally, stop the virtual machine with:
  • vnx_halt
    

    vnx_halt deletes some caches and log files and optionally lets you write a short message to /etc/vnx_rootfs_version file describing the latest modifications done.

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.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.

  • Do the modifications you want.
  • Finally, halt the system using:
  • vnx_halt
    

Updating VNXACED

You can automatically update the VNXACE daemon with the following command:

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

Known issues

  • When executing commands using vnx "--exe" option in virtual machines configured with exec_mode="cdrom", 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.