Cloning KVM virtual machine using CLI

To clone your VM and spawn new instances in KVML

# virt-clone --original {Domain-Vm-Name-Here} --auto-clone

OR

# virt-clone --original {Domain-Vm-Name-Here} --name {New-Domain-Vm-Name-Here} --auto-clone

OR

# virt-clone --original {Domain-Vm-Name-Here} \
--name {New-Domain-Vm-Name-Here} --file {/var/lib/libvirt/images/File.Name.here}

Continue reading “Cloning KVM virtual machine using CLI” »

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Install and Secure Redis on CentOS 7

Step 1 – Install and Enable Remi Repository

Firstly, we will add the Remi repository to the CentOS 7 system. The Remi repository provides the latest version of Redis package for our installation.

Before adding the Remi repository, let’s install the EPEL repository and yum utility packages.

sudo yum install epel-release yum-utils

Now add the Remi repository for CentOS 7 using the yum command below.

sudo yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm

After that, enable the ‘remi’ repository using the yum-config-manager tool as below.

sudo yum-config-manager --enable remi

The Remi repository has been added and enabled on the CentOS 7 system, check using the yum command Continue reading “Install and Secure Redis on CentOS 7” »

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Install MongoDB on CentOS 7

Follow the steps below to install the latest stable version of MongoDB on your CentOS server :

Enabling MongoDB repository

To add the MongoDB repository to your system, open your text editor and create a new YUM repository configuration file named mongodb-org.repo inside the /etc/yum.repos.d/ directory:

nano /etc/yum.repos.d/mongodb-org.repo
[mongodb-org-4.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc

If you want to install an older version of MongoDB, replace each instance of 4.0 with your preferred version. Continue reading “Install MongoDB on CentOS 7” »

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CentOS 7 XFS disk resizing

Couldn’t find any article that explained step by step how to resize the main disks volume in a CentOS 7 vm. In my example I started witha single disk of 8GB and expanded to 20GB. I have two partitions on disk sda

sda1 type Linux for boot
sda2 type Linux LVM for the remaining logical volumes

Space utilisation as following:

[root@vcd-c1-s1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 3.9G 8.8M 3.9G 1% /run
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/centos-root 6.2G 1.9G 4.4G 31% /
/dev/sda1 1014M 179M 836M 18% /boot
tmpfs 783M 0 783M 0% /run/user/0

We basically need to: Continue reading “CentOS 7 XFS disk resizing” »

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Install webmin on Centos 7 using Yum

Create and open this new file using your text editor:

sudo vi /etc/yum.repos.d/webmin.repo

Then add these lines to the file to define the new repository:

nano /etc/yum.repos.d/webmin.repo
[Webmin]
name=Webmin Distribution Neutral
#baseurl=http://download.webmin.com/download/yum
mirrorlist=http://download.webmin.com/download/yum/mirrorlist
enabled=1

Save the file and exit the editor. Continue reading “Install webmin on Centos 7 using Yum” »

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Install wkhtmltopdf 0.12.5 on Centos 7

Install Dependencies

yum install fontconfig libXext freetype libpng zlib libjpeg-turbo libpng libjpeg openssl icu libX11 libXext libXrender xorg-x11-fonts-Type1 xorg-x11-fonts-75dpi

Install wkhtmltopdf

sudo yum install -y https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox-0.12.5-1.centos7.x86_64.rpm

Test

wkhtmltopdf http://www.google.com google.pdf

Src::
https://otodiginet.com/software/tools/how-to-install-and-using-wkhtmltopdf-on-centos-7/
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Configure DomainKeys- DKIM (OpenDKIM) with Postfix on CentOS 7

OpenDKIM is method to digitally sign & verify emails on the mail servers using public & private keys. In other words opendkim implements the DKIM (DomainKeys Identified Mail) standard for signing and verifying email messages on a per-domain basis. DomainKeys are implemented to reduce the chances of outgoing mails to be marked as SPAM.

In this post we will demonstrate how to install & configure DomainKeys with postfix (MTA) on CentOS 7, i am assuming Postfix is already installed with following domain and hostname.

Hostname = mail5.freshdaymall.com
Domain = freshdaymall.com

Step:1 Set EPEL Repository using below rpm command

OpenDKIM package is not available in the default yum repositories but available in CentOS 7 EPEL repositories

[root@mail5 ~]# rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

Step:2 Install OpenDKIM Package using yum

[root@mail5 ~]# yum install -y opendkim

Step:3 Run below Command to create keys

Execute the below command to create public & private keys under folder “/etc/opendkim/keys” Continue reading “Configure DomainKeys- DKIM (OpenDKIM) with Postfix on CentOS 7” »

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Setup mail server on centos 7 using postfix and dovecot

Installing packages

Step 1 » Assign hostname for the server using the below command.

[root@krizna ~]# hostnamectl set-hostname mail.krizna.com

Step 2 » Make a host entry with your IP in /etc/hosts file.

172.27.0.51 mail.krizna.com

Step 3 » Now start installing packages.

[root@krizna ~]# yum -y install postfix dovecot

After package installation continue with postfix configuration. Continue reading “Setup mail server on centos 7 using postfix and dovecot” »

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How to fix CentOS 5 or 6 error: YumRepo Error: All mirror URLs are not using ftp, http[s] or file

The error looks like-

And here goes the resolution (please carefully update/use the exact CentOS version you are using, in my case it was CentOS 6.9)

1. Go to /etc/yum.repos.d/ directory:

# cd /etc/yum.repos.d/

2. Make copy of original file:

# cp CentOS-Base.repo CentOS-Base.repo.old

3. Open and edit file with any text editor:

# vi CentOS-Base.repo looks

4. After editing it should looks like: Continue reading “How to fix CentOS 5 or 6 error: YumRepo Error: All mirror URLs are not using ftp, http[s] or file” »

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Build a Centos 7 Repo

Install httpd

[root@www ~]# yum -y install httpd
# remove welcome page
[root@www ~]# rm -f /etc/httpd/conf.d/welcome.conf

Configure httpd. Replace server name to your own environment.

[root@www ~]# vi /etc/httpd/conf/httpd.conf
# line 86: change to admin's email address

ServerAdmin root@srv.world
# line 95: change to your server's name

ServerName www.srv.world:80
# line 151: change

AllowOverride All
# line 164: add file name that it can access only with directory's name

DirectoryIndex index.html index.cgi index.php
# add follows to the end

# server's response header

ServerTokens Prod
# keepalive is ON

KeepAlive On

[root@www ~]# systemctl start httpd
[root@www ~]# systemctl enable httpd

Install other required packages.

[root@dlp ~]# yum -y install rsync createrepo

Continue reading “Build a Centos 7 Repo” »

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