Category: Linux

Linux, Storage

GlusterFS Storage Setup on Two CentOS 7 Servers and Client

Jan 25, 2016 by Grzegorz Juszczak 5 Comments , , , , ,

glusterfs_logo
GlusterFS is a simple and easy to configure scalable network attached storage. GlusterFS is a distributed storage consisting of nodes (servers including storage bricks), which export their own local file system as a volume. Volumes can be mounted on client servers as a network storage using NFS and Gluster Fuse. GlusterFS provides failover, redundancy and anti split-brain mechanisms that act as a High Availability system, that’s why in many aspects it is similar to the well known clustering software like Veritas Cluster Suite.

In this tutorial we will install GlusterFS on two CentOS 7 based nodes. We will use KVM Virtual Machines to make things easier and faster, but our main intention is to show you how to install GlusterFS on physical hardware.
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Linux

Upgrade from Fedora 21 to Fedora 22 using DNF

Jan 3, 2016 by Grzegorz Juszczak 0 Comments , , ,

fedora_logo
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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Linux, Virtualization

How to Install Docker on Fedora 23

Jan 3, 2016 by Grzegorz Juszczak 0 Comments , ,

docker_logo
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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Bash, Linux

ifdata – network interface information tool – ifconfig alternative

Dec 28, 2015 by Grzegorz Juszczak 0 Comments , , , ,

linux-terminal
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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Linux, Storage

How to Create LVM Volume Group and Logical Volume

Nov 14, 2015 by Grzegorz Juszczak 0 Comments , , , ,

Create LVM Volume Group and Logical Volume
Logical Volume Manager (LVM) is a device mapper target that provides logical volume management for the Linux kernel. LVM allows to create Logical Volumes from underlying Physical Hard Disks (Physiacal Volumes). Logical Volumes can be easily extended and shrunk according to the file system capacity demands.

LVM Objects:
Physical Volume (PV): underlying physical storage for LVM. These are most often physical hard disks, but also can be: partitions, RAID volumes, etc…
Volume Group (VG): storage pool, created from one or more Physical Volumes.
Physical Extent: small chunk of Physical Volume, used during Volume Group creation.
Logical Extent: mapped to Physical Extent, acting as front-end chunk for Logical Volumes.
Logical Volume: group of Logical Extents, used by the system as hard drive partition.
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Linux, Security

Detect Intrusion and Check Linux File System Integrity with AIDE

Nov 11, 2015 by Grzegorz Juszczak 0 Comments , , , , , , ,

If you suspect that your system was compromised and files and/or their permissions were modified by the intruder, you can use AIDE to check your file system against some modifications.

AIDE (Advanced Intrusion Detection Environment) is a file integrity checker and intrusion detection program. AIDE is used to scan the system when it’s in known good state – it collects information about files and their permissions in the file system and writes gathered information to the database. Once the database is initialized it can be used to verify the integrity of the files in case of some compromise is suspected. All of the usual file attributes can be checked for inconsistencies.

In this tutorial we will show you how to install and deploy AIDE on CentOS/Fedora/RedHat.
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