A reference application is a sample application that is used as a guide for developers to learn and implement best practices for software development, testing, deployment, and operations within a specific technology stack or framework. It can serve as a blueprint for building and maintaining similar applications and can be used to demonstrate the use of tools, processes, and techniques for achieving high levels of automation, scalability, and reliability.

If you are learning how to deploy applications to Kubernetes of Virtual Machines in cloud, create your own tiny application.

In the Kubernetes Objects Required For A Typical Web Application post we talked about few Kubernetes objects that a web application developer should get accustomed to. In this post, we will extend the series and talk about more objects that can help web developers scale their applications.

As we delve deeper into Kubernetes topics, the demarcation of roles and skill sets start to reveal. In larger organizations, a dedicated team of infrastructure engineers design and make choices of network topology, IAC tooling and orchestration of the Kubernetes clusters and CI/CD pipelines. Typically, such DevOps engineers manage scaling and storage by installing the required controllers and CSI drivers. Application developers whose applications are deployed on the cluster maybe able to tune certain parameters of certain objects to manage the scaling needs of their applications. Depending on the situation, the developers maybe able to request and use storage volumes with certain restrictions. Regardless of the organization’s team structure, you should be able to learn about these Kubernetes concepts and objects and play with them locally on your laptop using Minikube.

In a previous post, we discussed using age to manage secrets in Git repositories. In this post, let’s improve our secrets management workflow in Git repositories using SOPS.

sops is an editor of encrypted files that supports popular configuration formats such as YAML and various encryption techniques such as age.

Read the blog post about age to install the package and creating the key file.

This time, we will use sops to perform encryption and decryption operations instead of the age command.

When you begin your career in IT, you will be required to learn Git sooner or later. Git is a key technology used in everyday software engineering and DevOps. It has become persuasive and quintessential. There is no need to hard sell Git to anyone at this point.

There is a lot to learn about Git. The good news is that you can start with a subset of Git. There is a no need to become a Git master on your day one of software engineering or DevOps engineering. You can follow a tutorial and take home a Git workflow on day one. In about three days of studying and practising Git, you will be ready to use Git in software engineering and DevOps workflows.

KVM (Kernel-based Virtual Machine), libvirt, and QEMU are three components that work together to provide a virtualization solution on Linux systems.

KVM is a virtualization infrastructure built into the Linux kernel that allows it to run multiple virtual machines (VMs) on a single physical host. It provides the underlying virtualization technology, such as hardware acceleration for virtualized CPU and memory, and device emulation.

NFS Server

To run your own NFS (Network File System) server, you’ll need to first install Linux on your server. I’d go with Debian, Ubuntu or CentOS distributions. Once you’ve done that, you can install the NFS server software, which is typically included with most Linux distributions. After the NFS server software is installed, you’ll need to configure it to specify which directories on the server should be shared with NFS clients, and what type of access they should have. This typically involves editing the server’s configuration file, which is typically located at /etc/exports. Once the server is configured, you can start the NFS server and begin sharing files with NFS clients. To access the shared files, the NFS clients will need to mount the NFS share using the mount command.

There are many applications and technologies enabled by VPN. We will focus on one of them in this post: client VPN.

Connecting To A Private Network

If the server you are trying to access is on a private network, you can use a VPN to connect to the network as if you were physically present on the same network. This can be useful if you need to access resources or devices that are only available on the private network.

syslog

Syslog is a standard for logging system events on Unix and Linux systems. It is typically used to collect and store log messages from various applications and system components, such as the kernel, system libraries, and applications. Syslog uses a client-server model, where each client application sends log messages to a central syslog server, which then stores the messages in a log file. The syslog server can also forward the log messages to other syslog servers or send them to a log management system for further analysis. Syslog uses a simple text-based format for its log messages, which makes it easy to read and analyze. It also supports multiple levels of severity, allowing applications to categorize their log messages based on importance.

There are many tools and software programs that can be used for monitoring and performance analysis on Linux systems. Some popular options include:

• top - This is a command-line utility that shows real-time information about the processes running on a Linux system, such as their CPU and memory usage.
• htop - This is a more advanced version of top that provides a more user-friendly interface and additional features, such as the ability to sort processes by different metrics and to kill processes.
• sar - This is a command-line utility that collects and displays performance metrics for a Linux system over time. It can be used to analyze CPU, memory, I/O, and network usage, as well as other metrics.
• iostat - This is a command-line utility that shows real-time information about I/O performance on a Linux system. It can be used to monitor the performance of disks and other storage devices.
• vmstat - This is a command-line utility that shows real-time information about various system resources, such as memory, CPU, and I/O. It can be used to monitor the overall health of a Linux system.
• netstat - This is a command-line utility that shows information about network connections on a Linux system. It can be used to monitor the status of network connections and to diagnose networking issues.

There are also many modern monitoring tools and software programs available for Linux, such as Prometheus and Zabbix. These tools typically offer more advanced features and capabilities than the built-in Linux utilities, such as the ability to collect and store metrics over time, and to generate alerts when certain conditions are met.

To run your own email server using Linux and other open source software, you’ll need to first choose a Linux distribution and install it on your server. I’d go with either Ubuntu, Debian or Rocky Linux. Once you’ve done that, you can choose an email server software that is compatible with Linux, such as Postfix or Exim. After installing and configuring the email server software, you’ll need to set up DNS records and configure authentication and encryption to ensure that your email server is secure. Finally, you’ll need to test your email server to make sure it is working properly and can send and receive messages.