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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Openstack, besides Horizon GUI Dashboard, can also be configured via command-line interface using commands in Bash. Below we present a list of common and useful commands for your reference.
Note: in OpenStack command-line interface you have to source appropriate keystonerc file in order to be able to invoke OpenStack commands within the specified Project Tenant. Sourcing of keystonerc file imports Tenant User/Admin credentials to environment variables during user session.
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In this article we would like to introduce you two simple and smart Linux command line tools to monitor bandwidth usage on all network interfaces in the real time: iftop and nload.
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During OpenStack deployment and testing you may need to quickly create: project tenants, tenant users, networks, routers, security groups, etc… just to check, if Cloud is working properly.
Instead of arduous clicking all this stuff in Horizon dashboard, you can use the below Bash script, which will quickly create:
– multiple project tenants
– 2 tenant users (admin, member)
– tenant networks, sub-networks
– routers
– router gateways (to existing public network)
– tenant ports in routers
– security groups (Allow all TCP,UDP,ICMP ingress/egress)
– cirros glance image (cirros-0.3.4-x86_64-disk.img)
Download script: tenant_setup.sh
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OpenStack is quite reliable Cloud solution, that provides extensibility and scalability. That means, if the Cloud is running out of resources for new tenants and instances, it can be easily extended with new Hypervisors (Compute nodes) practically on-line.
In this tutorial we will extend existing OpenStack installation (Controller node, Compute node) with new Compute0 node on-line, without shutting down existing nodes. The easiest and fastest way to extend existing Openstack Cloud on-line is to use Packstack, the automated installer script.
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If the server is placed in network behind firewall and outgoing traffic is blocked by firewall, the only chance to install new packages from remote repo is through proxy (if that exists).
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