A Passionate Techie

KVM is an open source hardware virtualization software through which we can create and run multiple Linux based and windows based virtual machines simultaneously. KVM is known as Kernel based Virtual Machine because when we install KVM package then KVM module is loaded into the current kernel and turns our Linux machine into a hypervisor. In this post first we will demonstrate how we can install KVM hypervisor on CentOS 7.x and RHEL 7.x and then we will try to install virtual machines. Before proceeding KVM installation, let’s check whether your system’s CPU supports Hardware Virtualization. Run the beneath command from the console. [root@linuxtechi ~]# grep -E '(vmx|svm)' /proc/cpuinfo We should get the word either  vmx  or  svm  in the output, otherwise CPU doesn’t support virtualization. Step:1 Install KVM and its associate packages Run the following yum command to install KVM and its associated packages. [root@linuxtechi ~]# yum install qemu-kvm qemu-img virt-manager libvir...

1. Change to root User Bash su - ## OR ## sudo -i 2. Install Fedora or RHEL Repo Files Bash cd /etc/yum.repos.d/ ## Fedora 26/25/24/23/22/21/20/19/18/17/16 users wget http://download.virtualbox.org/virtualbox/rpm/fedora/virtualbox.repo ## CentOS 7.4/6.9 and Red Hat (RHEL) 7.4/6.9 users wget http://download.virtualbox.org/virtualbox/rpm/rhel/virtualbox.repo 3. Update latest packages and check your kernel version Update packages Bash ## Fedora 26/25/24/23/22 ## dnf update ## Fedora 21/20/19/18/17/16 and CentOS/RHEL 7/6/5 ## yum update While executing yum update if you get any dependency errorfor glibc use the following to resolve it: rpm -qa | grep glibc You may see duplicates for either glibc or glibc common. There might be a common version in between any two packages of glibc and glibc-common. Remove the package which has uncommon version. You can also check for duplicates with the following command: yum list --showduplicates glibc rpm -e glibc-common-2.17-196.el7 rpm -qa kernel |...

currently with docker you are limited to only linux machines and apps. It is like installing various zip files on your os. because of the use of base image we can save space.All the containers use the same base image. If you want 100 containers in traditional vm env you would have needed 100GB space considering 1gb per image but with docker you will need only 1gb of space. Suppose if you need emacs and apache then docker will add to separate images for it on top of each other and with the base image it will form a union image. this image is readonly so to write in it docker will place a writable container and the whole set container:image(apache)+image(emacs)+base image will make a whole container in the docker.  But the writable container is not persistent. Docker boots the image/ image layers on top f each other. apt-cache search docker.io ---will display a list of packages containing docker apt-chache show docker.io ---- will display all details of packaage Check if it is latest ver...

if you and your friend have vm and want to sync up you may have to transfer 20gb of file. but with docker docker diff to check the difference then docker commit then docker push which will only be the change. docker containers: are actual containers running the applications and includes os, user added files, and meta data docker images: helps to launch docker containers docker file: is a file containing instructions that help automate image creation layer: each file system that is stacked when docker mounts rootfs. Install docker using: sudo rpm install docker docker commands: docker pull: pull a pre-built image from public repos docker run: run in 3 modes background,foreground,interactive docker logs: logs of running logs docker commit: save container state docker images: list of all images docker diff: changes in files and directories docker build: build docker images from dockerfiles docker inspect: low level info about containers docker attach: interact with running container doc...