Centos 7 Released

CentOSCentos 7 was released on 7/7/2014.  Here's some useful info, new feature highlights and download links.  Enjoy.

  • There is a supported upgrade path from Centos 6.5 to Centos 7.  Details are here.  Tools for this are not available yet but should be soon
  • There is a plethora of download options, including Gnome and KDE live CDs
  • 512MB (actually 406MB) is the minimum amount of available RAM required for the installer to successfully run.  Less than 406MB will result in fatal error
  • Screen resolution during installation should be set to 1024 X768 and higher.  There is a known issue that images at the bottom of the screen are clipped if it is 800 X 600

Cool New Stuff

As one would expect with a new major release there are plenty of enhancements / new features in this release.  Here are some highlights:

  • Kernel 3.10.0 up from 2.6.32.  This should mean that live kernel patching with kpatch is possible and I believe it will also benefit Centos adoption for OpenStack installation as I think this will make products like CEPH easier to install (than on CentOS 6.x)
  • Support for Linux Containers (LXC) with a Docker format.  Another big one for the cloud.  There is a tremendous amount of interest in the latest version of Linux Containers in the cloud world.  They can offer much leaner resource utilisation than a full-blown virtual machine and offer full application isolation and scheduling.  Not yet considered as secure as a separate virtual machine, they offer potential in the PaaS world to provide rapid application scale-out due to the potentially low millisecond 'boot-time' of a new container
  • XFS as the default file system.  XFS is a 64-bit journaling file system first released in 1994.  The file system can be scaled to 16 exbibytes (1024 pebibytes), so in that sense it represents a significant increase over ext4 at 16 tebibytes (1024^2 increase).  For a full comparison of file systems start here
  • Open VMWare tools out of the box (instead of adding a repository and installing them from there)
  • LVM snapshots for ext4 and XFS
  • ​Introduction of new performance monitoring system called Performance Co-Pilot
  • A standard remote API - OpenLMI
  • The inclusion of systemd process manager and many more.  More details can be found here

Quick Manual Install

First thing to do is a quick manual install.  I setup a VM on VMWare ESX 5.1 with 2GB RAM, 1 vCPU, 16GB disk on LSI Logic Parallel SCSI controller and a single E1000 network interface.  Process was as follows:

  • Booted off ISO and entered setup
  • Configured UK locale
  • Set time zone to Madrid/CET.  Attempted to use NTP
  • Selected the virtual disk onto which the OS was to be installed
  • Left the default 'minimal install' selected
  • Configure the network interface and connected it automatically
  • Built machine, rebooted and logged on
  • Tested basic networking and installation of Open VMWare tools

Here are a couple of observations:

  • As can be seen in screenshots below, portion of the screen is chopped with low resolution display.  Scrolling solves this minor issue
  • I wasted a bit of time in the Date/Time UI.  Simply because I wanted to add my NTP server and remove the default ones.  Automated install will sort this but I may take a closer look at manual install later.  It was not immediately obvious how to remove the default time servers or at least promote mine.  Additionally, because the network was not configured at that point it was a pointless exercise.  After configuring the network I returned to NTP setup.  It allowed me to activate Network Time at that point but it immediately set the time incorrectly.
  • If you want the network interface to work straight after building, you will first need to switch on the interface in the 'Network and Hostname' UI and then within there navigate into the network setup and then into the 'general' tab for the NIC and tick the 'Automatically connect to this network when it is available'
  • had to run a 'yum install -y net-tools' to get ifconfig (which is installed under CentOS 6.x minimal install)
  • Minimal install is the default selection.  It installs 297 packages

First boot into installLocale selectionDate and timeDisk selectionMain install formNetwork interface currently disconnectedNetwork interface now connectedGeneral tab in network interface UI dialogue boxMain panel, all major tasks completePackages installing with outstanding tasksPassword entry with complexity checkingPackages installing with no further tasks to completeInstallation complete awaiting a rebootBooted and working with network connectivityBefore Open VMWare Tools are installedAfter Open VMWare Tools are installed

PS - Add EPEL repo if you wish with:

rpm -Uvh http://dl.fedoraproject.org/pub/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm