qemu-img is a QEMU disk image utility, which allows us to create, convert and modify images offline. It can handle all image formats supported by QEMU (including qcow2 and raw image format).
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Sometimes I need to edit files inside qcow2 or raw image, but for some reason I don’t want to launch the image in KVM or in Openstack cloud. The image can be edited offline using virt-edit tool.
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Starting from Fedora release 21 (Twenty One), Fedora can be upgraded using DNF system upgrade, which is recommended upgrade method for Fedora 21 and later releases. DNF is a kind of successor for FedUp (FEDora UPgrader), which is now obsolete, not supported any more by Fedora Project and should not be used in any circumstances.
In this article we will upgrade Fedora release 21 (Twenty One) to Fedora release 22 (Twenty Two) in five simple steps, using DNF system upgrade method.
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Docker is a software which automates the deployment of applications inside Linux containers, by providing an additional layer of abstraction. This guarantees that it will always run the same, regardless of the environment it is running in. Docker uses the resource isolation features of the Linux kernel such as cgroups and kernel namespaces to allow independent containers to run within a single Linux instance, avoiding the overhead of starting and maintaining virtual machines.
In this tutorial we will setup and launch Docker software on Fedora 23 (64-bit) release.
Prerequisites for Docker installation on Fedora release:
Fedora version: Fedora 22 (64-bit) or higher
kernel version: 3.10 or higher
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ifdata is a quick, lightweight and simple tool to display network interface information in Linux, which can be used as an alternative for ip addr show or ifconfig.
Sometimes I want to quickly find out, if the particular network interface exists in the system or I want to display it’s IP address or MTU value only. If I used ifconfig for this case, I would have to parse the output using grep or other tools. ifdata resolves this problem in more sophisticated manner – it utilizes parameters to better control the output we want to obtain. This is another reason why ifdata is more friendly for use in BASH scripting.
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In this tutorial we will install OpenStack Liberty release from RDO repository on one node (all-in-one installation) based on CentOS 7 / RHEL 7 using packstack installer script.
In all-in-one configuration all OpenStack nodes (controller node, compute node, network node) are installed on a single machine. This type of configuration can be deployed very easy and fast for testing purposes, also on KVM machines, when no physical hardware is available.
Environment used:
public network (Floating IP network): 192.168.2.0/24
public network gateway: 192.168.2.1
node IP: 192.168.2.32
node OS: CentOS 7.1 64bit OS
node hardware: 2GHz CPU / 4GB RAM / 1 ethernet card
OpenStack version: Liberty
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