Introduction The Docker daemon is a background process that manages Docker containers and is responsible for the creation, execution, and deletion of containers. One key component of the Docker daemon is the Docker daemon socket, which is used to communicate with the daemon from the Docker CLI and other applications. It is important to secure the Docker daemon socket to prevent unauthorized access to the Docker daemon and to protect sensitive information that may be exposed through the socket. In this article, we will discuss the location and default permissions of the Docker daemon socket, potential security risks, and best ... Read More

Introduction Splash is a powerful tool for rendering JavaScript-based websites, making it an essential tool for web scraping and data extraction. In this tutorial, we will show you how to run Splash using Docker Toolbox, an older version of Docker that is no longer being maintained but is still available for download. Prerequisites Before you can get started, you will need to install Docker Toolbox on your machine. Docker Toolbox is a version of Docker that is designed to run on older systems and/or systems without native virtualization. It is available for Windows, macOS, and Linux. Follow the steps ... Read More

Introduction Embedded Docker resource files are files included in a Docker image rather than stored on the host file system or an external network location. These files can be useful for including configuration files, scripts, or other resources that are needed by the applications or processes running in the Docker container. You can reference embedded Docker resource files in several different ways, including using file path URLs. This article explains what file path URLs are and how to use them to reference embedded Docker resource files. We will also provide tips and examples to help you use file path URLs ... Read More

Introduction In a Docker Tomcat 8 container, you may want to change the user configuration to add or modify users and roles. This modification can be useful for tasks like securing access to the Tomcat 8 instance or setting up different levels of permissions for different users. This article explains how to change the user configuration in a Docker Tomcat 8 container. We cover the steps involved in modifying the tomcat-users.xml file, building a new Docker image with the modified configuration, and running a Docker container from the new image. Prerequisites Before changing the user configuration in a Docker Tomcat ... Read More

JMX and its use in Java applications JMX (Java Management Extensions) is a Java technology that provides a way to manage and monitor Java applications. It exposes a set of APIs and MBeans (Java objects that represent resources to be managed) that can be used to monitor and control the behaviour of a Java application. JMX is commonly used in Java-based applications to monitor performance metrics such as memory usage, CPU utilization, and thread counts, as well as to manage and configure the application at runtime. Accessing JMX from outside a Docker container When running a Java application in a ... Read More

Overview If you are using Docker Compose to define and run multi-container Docker applications, you may want to specify custom configuration files or directories for your application. Fortunately, Docker Compose provides the --config option, which allows you to do just that. The --config option is used to specify a single configuration file or a directory containing multiple configuration files for Docker Compose. To use it, you can pass it as an argument to the docker-compose command. For example − $ docker-compose --config /path/to/custom/config.yml up This command would tell Docker Compose to use the configuration file located at /path/to/custom/config.yml ... Read More

Introduction Vagrant is a tool for building and managing development environments using virtualization software such as VirtualBox. It allows you to define and configure a development environment in a Vagrantfile and then spin up and tear down virtual machines quickly and easily. By using Docker and Vagrant together, you can create a flexible and reproducible development environment that is easy to set up and maintain. This article discusses the best way to install Docker on Vagrant, including the prerequisites, installation steps, and verification. Prerequisites for installing Docker on Vagrant Before installing Docker on Vagrant, you must ensure you have the ... Read More

Introduction XPath is a powerful language used for navigating and selecting elements within an XML document. It is commonly used in conjunction with XSLT, a language used for transforming XML documents, to extract specific information from a document. In this article, we will discuss how to evaluate XPath expressions in the Linux command line, using the command-line tool xmllint. Installing xmllint Before we can begin evaluating XPath expressions in the Linux command line, we must first install xmllint. xmllint is part of the libxml2 library, which is included in most Linux distributions. To check if xmllint is already installed on ... Read More

Introduction In Linux, hidden files, also known as dotfiles, are files whose names begin with a dot (.) character. These files are often used to store configuration data or other important information that should not be changed or deleted by the user. If you have a directory with a large number of hidden files and you want to move them all to the root directory, there are several ways to do this. In this tutorial, we will discuss two methods for moving all files, including hidden files, from a directory to its home directory in Linux: the mv command and ... Read More

Introduction Cron is a utility in Linux that allows users to schedule commands or scripts to run automatically at a specific date and time. However, sometimes it may be necessary to ensure that a cron job does not run more than once at a time. In this article, we will discuss two ways to prevent overlapping cron tasks: using process tracking and using a “.pid” file. Locate running instances by process One way to avoid overlapping a cron task run is to check for the presence of the task's process before running it. This can be done using the pgrep ... Read More