Tag Archives: centos

RHEL/Fedora + Docker (and SELinux) – slides from my talk @ Krakow DevOPS meetup


It’s still fresh – I gave this talk a few hours ago at DevOPS meetup here in Krakow. There’s Dan Walsh’s surprise included ;)

RHEL/Fedora + Docker (and SELinux) from Maciej Lasyk

Kraków DevOPS Meetup #3: Docker


Tommorow I’ll give another talk at #Kraków #DevOPS meetup which will take place in The Base office. I’ll cover the subject of Docker integration with Red Hat / CentOS and Fedora as well as I’ll tell something about Docker SELinux collaboration.

Presentations / Lightning talks:

  • Communication between Docker containers – Zaiste 
  • RedHat/Fedora/CentOS & SELinux + Docker – we have a long way to go babe – Maciek Lasyk 
  • Docker + Ansible + MariaDB + tt-rss – Łukasz Proszek
  • Local development with Docker – Mirosław Nagaś
  • + Q&A with all speakers 

If you’d like to join – just register at the meetup webpage: http://www.meetup.com/Krakow-DevOps/events/165916812/

Way to go RedHat! RHEL 6.5 released


So it finally happened – we’ve got 6.5 in stock :) Also DistroWatch alerted about Centos 6.5 release: http://distrowatch.com/?newsid=08190

What’s interesting here? (Listing only those ones that I think are really worth of mentioning – for full list see references in the bottom of this post):

  • Kernel / New Supported Compression Formats for makedumpfile:In Red Hat Enterprise Linux 6.5, the makedumpfile utility supports the LZO and snappy compression formats. Using these compression formats instead of the zlib format is quicker, in particular when compressing data with randomized content.
  • Networking:
    • Precision Time Protocol – An implementation of the Precision Time Protocol (PTP) according to IEEE standard 1588-2008 for Linux was introduced as a Technology Preview in Red Hat Enterprise Linux 6.4. The PTP infrastructure, both kernel and user space, is now fully supported in Red Hat Enterprise Linux 6.5. Network driver time stamping support now also includes the following drivers: bnx2x, tg3, e1000e, igb, ixgbe, and sfc.
    • Analyzing the Non-Configuration IP Multicast IGMP Snooping Data – Previously, the bridge module sysfs virtual file system did not provide the ability to inspect the non-configuration IP multicast Internet Group Management Protocol (IGMP) snooping data. Without this functionality, users could not fully analyze their multicast traffic. In Red Hat Enterprise Linux 6.5, users are able to list detected multicast router ports, groups with active subscribers and the associated interfaces.
    • Network Namespace Support for OpenStack – Network namespaces (netns) is a lightweight container-based virtualization technology. A virtual network stack can be associated with a process group. Each namespace has its own loopback device and process space. Virtual or real devices can be added to each network namespace, and the user can assign IP addresses to these devices and use them as a network node.
  • Virtualization / KVM:
    • Native Support for GlusterFS in QEMU – Native Support for GlusterFS in QEMU allows native access to GlusterFS volumes using the libgfapi library instead of through a locally mounted FUSE file system. This native approach offers considerable performance improvements.
    • Support for Dumping Metadata of Virtual Disks – This low-level feature uses the newly introduced command option qemu-img map to create an index that allows a qcow2 image to be mapped to a block device via LVM. As a result, virtual machine images (with the virtual machine shutdown) can be accessed as block devices. This is useful for backup applications that are now able to read guest image contents without knowing the details of the qcow2 image format.
    • CPU Hot Plugging for Linux Guests – CPU hot plugging and hot unplugging are supported with the help of the QEMU guest agent on Linux guests; CPUs can be enabled or disabled while the guest is running, thus mimicking the hot plug or hot unplug feature.
    • Application-Aware freeze and thaw on Linux Using qemu-ga Hooks – Similar to the Windows VSS version, application-consistent snapshots can be created with the use of scripts that attach to the QEMU guest agent running on the guest. These scripts can notify applications which would flush their data to the disk during a freeze or thaw operation, thus allowing consistent snapshots to be taken.
    • Host and Guest Panic Notification in KVM – A new pvpanic virtual device can be wired into the virtualization stack such that a guest panic can cause libvirt to send a notification event to management applications. This feature is introduced in Red Hat Enterprise Linux 6.5 as a Technology Preview. Note that enabling the use of this device requires the use of additional qemu command line options; this release does not include any supported way for libvirt to set those options.
  • Storage:
    • Full Support of fsfreeze – The fsfreeze tool is fully supported in Red Hat Enterprise Linux 6.5. The fsfreeze command halts access to a file system on a disk. fsfreeze is designed to be used with hardware RAID devices, assisting in the creation of volume snapshots. For more details on the fsfreeze utility, refer to the fsfreeze(8) man page.
    • pNFS File Layout Hardening – pNFS allows traditional NFS systems to scale out in traditional NAS environments, by allowing the compute clients to read and write data directly and in parallel, to and from the physical storage devices. The NFS server is used only to control meta-data and coordinate access, allowing predictably scalable access to very large sets from many clients. Bug fixes to pNFS are being delivered in this release.
    • Support of Red Hat Storage in FUSE – FUSE (Filesystem in User Space) is a framework that enables development of file systems purely in the user space without requiring modifications to the kernel. Red Hat Enterprise Linux 6.5 delivers performance enhancements for user space file systems that use FUSE, for example, GlusterFS (Red Hat Storage).
    • TRIM Support in mdadm – The mdadm tool now supports the TRIM commands for RAID0, RAID1, RAID10 and RAID5.
  • Clustering – pacemaker Fully SupportedPacemaker, a scalable high-availability cluster resource manager, which was previously included as a Technology Preview, is now fully supported in combination with Red Hat OpenStack deployments.

So now let’s yum update ;)