Pushing Docker Images to a Docker Repository

The next logical step after creating a new image from an existing image is to share it with a select few of your friends, the whole world on Docker Hub, or other Docker registry that you have access to. To push an image to Docker Hub or any other Docker registry, you must have an account there.

This section shows you how to push a Docker image to Docker Hub. To learn how to create your own private Docker registry, check out How To Set Up a Private Docker Registry on Ubuntu 14.04.

To push your image, first log into Docker Hub.

docker login -u docker-registry-username

You’ll be prompted to authenticate using your Docker Hub password. If you specified the correct password, authentication should succeed. Continue reading “Pushing Docker Images to a Docker Repository” »

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Docker Commands

Working with Docker Images

Docker containers are built from Docker images. By default, Docker pulls these images from Docker Hub, a Docker registry managed by Docker, the company behind the Docker project. Anyone can host their Docker images on Docker Hub, so most applications and Linux distributions you’ll need will have images hosted there.

To check whether you can access and download images from Docker Hub, type:

docker run hello-world

The output will indicate that Docker in working correctly:

Output
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
1b930d010525: Pull complete
Digest: sha256:41a65640635299bab090f783209c1e3a3f11934cf7756b09cb2f1e02147c6ed8
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.
...

Docker was initially unable to find the hello-world image locally, so it downloaded the image from Docker Hub, which is the default repository. Once the image downloaded, Docker created a container from the image and the application within the container executed, displaying the message. You can search for images available on Docker Hub by using the docker command with the search subcommand. For example, to search for the Ubuntu image, type: Continue reading “Docker Commands” »

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Install Docker on Debain 10

Installing Docker

The Docker installation package available in the official Debian repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.

First, update your existing list of packages:

sudo apt update

Next, install a few prerequisite packages which let apt use packages over HTTPS:

sudo apt install apt-transport-https ca-certificates curl gnupg2 software-properties-common

Then add the GPG key for the official Docker repository to your system: Continue reading “Install Docker on Debain 10” »

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Installing wkhtmltopdf on Debian 7.8

Installing wkhtmltopdf on Debian 7.8 to dynamically create PDF documents from HTML.

apt-get update
aptitude install xfonts-base xfonts-75dpi fontconfig
mkdir ~/src/wkhtmltopdf -p
cd ~/src/wkhtmltopdf
wget https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.2.1/wkhtmltox-0.12.2.1_linux-wheezy-amd64.deb
dpkg -i wkhtmltox-0.12.2.1_linux-wheezy-amd64.deb

Src:
https://fedir.github.io/web/blog/2015/09/01/install-wkhtmltopdf-on-debian-7.8
https://github.com/wkhtmltopdf/wkhtmltopdf/releases/0.12.2.1/
https://github.com/wkhtmltopdf/packaging/releases/0.12.6-1
https://stackoverflow.com/questions/38262173/how-to-correctly-install-wkhtmltopdf-on-debian-64-bit

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Easyengine installaiton on Debian 10

Install Easyengine WordPress on a Debian 10 VM (mine was a KVM).

The following procedure will install EE with following components;

  • Docker
  • WordPress Core
  • MariaDB
  • Nginx Server PHP-FPM
  • Redis Cache
  • Let’s encrypt SSL

Install EasyEngine on Linux

wget -qO ee rt.cx/ee4 && sudo bash ee
ee site create your_domain --type=wp --ssl=le --cache

For detailed installation or customizing your requirement, you may visit- https://easyengine.io/commands/site/create/ Continue reading “Easyengine installaiton on Debian 10” »

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Ubuntu Firewall – UFW useful commands

Prerequisites

To follow this tutorial, you will need one Debian 10 server with a sudo non-root user, which you can set up by following Steps 1-3 in the Initial Server Setup with Debian 10 tutorial.

Step 1 – Installing UFW

Debian does not install UFW by default. If you followed the entire Initial Server Setup tutorial, you will have installed and enabled UFW. If not, install it now using apt:

sudo apt install ufw

We will set up UFW and enable it in the following steps.

Step 2 — Using IPv6 with UFW (Optional)

This tutorial is written with IPv4 in mind, but will work for IPv6 as long as you enable it. If your Debian server has IPv6 enabled, you will want to ensure that UFW is configured to support IPv6; this will ensure that UFW will manage firewall rules for IPv6 in addition to IPv4. To configure this, open the UFW configuration file /etc/default/ufw with nano or your favorite editor:

sudo nano /etc/default/ufw

Then make sure the value of IPV6 is yes. It should look like this:

/etc/default/ufw excerpt
IPV6=yes

Continue reading “Ubuntu Firewall – UFW useful commands” »

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Setup Percona on Debian 7

MySQL multi-master replication is an excellent feature within MySQL. However, there is only one problem; standard multi-master replication seems to never be as stable as something like master-slave replication. It is always in need of attention. That is where Percona comes into play. The Percona team has developed an amazing product dubbed Percona XtraDB cluster. XtraDB features world class multi-master replication powered by Galera. So, what are we waiting for? Let’s get started.

Prerequisites
A Linux distro of your choice. In this guide, we will be using Debian 7. You can use a different distro if you would like. (Note that you may need to adapt this guide to work with the distro of your choice)
Two nodes running the same OS. Basic knowledge of the command line and SSH.

Getting Started

SSH into your virtual machines.

VM 1:
ssh root@xxx.xxx.xxx.xxx
VM 2:
ssh root@yyy.yyy.yyy.yyy

Add Percona’s repositories.
On both nodes, execute the following command:

echo -e "deb http://repo.percona.com/apt wheezy main\ndeb-src http://repo.percona.com/apt wheezy main" >> /etc/apt/sources.list.d/percona.list && apt-key adv --keyserver keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A

Now we need to update the sources:

apt-get update

Install Percona-XtraDB Cluster

The installation is straightforward: Continue reading “Setup Percona on Debian 7” »

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OpenDKIM Postfix SMTP Relay Server on Debian -7

Install OpenDKIM

Before starting the installation, a system update is recommended:

sudo apt-get update
sudo apt-get dist-upgrade

Install OpenDKIM and it’s dependencies:

sudo apt-get install opendkim opendkim-tools

Additional packages will be listed as dependencies, type yes and press Enter to continue.

Configure OpenDKIM

A couple of files must be created and edited in order to configure OpenDKIM.

Nano will be used as an editor because it’s installed by default on DigitalOcean droplets and it’s simple to operate:

navigate with the arrow keys
exit without saving changes: press CTRL + X and then N
exit and save changes: press CTRL + X and then Y, and finally press Enter
Important: replace every instance of example.com with your own domain in all commands and configuration files. Don’t forget to save your files after editing.

Let’s start with the main configuration file: Continue reading “OpenDKIM Postfix SMTP Relay Server on Debian -7” »

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