OpenStack networking topology is pretty complicated structure, even with it’s, let’s say, default configuration based on OVS (OpenVSwitch), not even mentioning about additional overlays, like OpenDaylight or Nuage.
If you are troubleshooting network issues in regard to a particular Instance (VM), it’s good to locate network overlay interfaces (qbr, qvo) assigned to that Instance to have a starting point to begin your network analysis from. You can then analyze inbound/outbound traffic on those interfaces using network protocol analyzers, like tcpdump/wireshark.
Below you can find few steps, how to locate qbr,qvo interfaces belonging to a particular Instance:
Continue reading “How to find qbr,qvo interfaces of the particular Instance in OpenStack”
Oracle VM VirtualBox is a flexible open-source hypervisor for x86 computers from Oracle Corporation initially developed by Innotek GmbH. It runs on many platforms including: Linux, Windows, Solaris, providing great virtualization environment to run multiple VMs at a time.
In this tutorial we present how to install VirtualBox 5.1 on Fedora 23 from RPMs in few simple steps.
Continue reading “How to Install VirtualBox 5.1 on Fedora 23 from RPMs”
KVM (Kernel-based Virtual Machine) is a virtualization infrastructure for the Linux which requires a processor with hardware virtualization extension to be able to host guest sytems. KVM is convenient solution to test and try different operating systems if you don’t have a possibility to purchase expensive and power consuming physical hardware.
The below tutorial presents KVM (QEMU) installation and setup along with Linux Bridge configuration on CentOS7 / RedHat7 operating system.
Continue reading “Install and Configure KVM (Bridge Net Interface) on CentOS 7 / RHEL 7”
If you transfer qcow2 images very frequently across OpenStack Clouds or between KVM and Openstack environments, they can quickly grow larger. Luckily qcow2 image size can be decreased to reasonable values using qemu-img tool. Below we present how to shrink Openstack/KVM qcow2 image.
Continue reading “How to shrink OpenStack qcow2 image using qemu-img”
Have you ever wondered if the server you bought at the hosting provider is in fact a dedicated server or just a VPS and what is the underlying virtualization environment your server runs on?
virt-what provides us the ability to detect if we are running in a virtual machine or on bare-metal (real hrdware). virt-what detects common types of virtualization: hyperv, kvm, openvz, qemu, virtualbox, vmware, xen, etc…
Continue reading “virt-what: Check if your remote server runs in virtual environment”
OpenStack Instance operating system can be configured right after the Instance boot using cloud-init package and user data mechanism. For example we can inject a configuration file to the Instance to set some system variables, set hostname or install a package upon Instance boot time. cloud-init supports few input formats of user data, for example: BASH scripts or cloud config files.
Continue reading “Configure OpenStack Instance at boot using cloud-init and user data”
OpenStack Snapshots can be utilized to backup Instance before some critical changes are made on Instance OS or to migrate Instance to the new OpenStack Cloud.
In this tutorial we will create snapshot from existing Instance to launch it in different Cloud, but you can also create snapshot just to backup the Instance and restore it’s state later in the same Cloud, if needed.
Continue reading “OpenStack: Create Instance Snapshot to backup or migrate Instance”
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).
Continue reading “Convert qcow2 to raw image and raw to qcow2 image”
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.
Continue reading “Edit qcow2 or raw image files offline using virt-edit”
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
Continue reading “How to Install Docker on Fedora 23”