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Deliver SaaS According Twelve-Factor App

If you haven't heard of the twelve-factor app , it gives us a recommendation or a methodology for developing SaaS or web apps structured into twelve items. The recommendation has some connections with microservice architecture and cloud-native environments which become more popular today. We can learn the details on its website . In this post, we will do a quick review of the twelve points. One Codebase Multiple Deployment We should maintain only one codebase for our application even though the application may be deployed into multiple environments like development, staging, and production. Having multiple codebases will lead to any kinds of complicated issues. Explicitly State Dependencies All the dependencies for running our application should be stated in the project itself. Many programming languages have a kind of file that maintains a list of the dependencies like package.json in Node.js. We should also be aware of the dependencies related to the pla...

Rangkaian Sensor Infrared dengan Photo Dioda

Keunggulan photodioda dibandingkan LDR adalah photodioda lebih tidak rentan terhadap noise karena hanya menerima sinar infrared, sedangkan LDR menerima seluruh cahaya yang ada termasuk infrared. Rangkaian yang akan kita gunakan adalah seperti gambar di bawah ini. Pada saat intensitas Infrared yang diterima Photodiode besar maka tahanan Photodiode menjadi kecil, sedangkan jika intensitas Infrared yang diterima Photodiode kecil maka tahanan yang dimiliki photodiode besar. Jika tahanan photodiode kecil maka tegangan V- akan kecil . Misal tahanan photodiode mengecil menjadi 10kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 10 / (10+10) x Vcc V- = (1/2) x 5 Volt V- = 2.5 Volt Sedangkan jika tahanan photodiode besar maka tegangan V- akan besar (mendekati nilai Vcc). Misal tahanan photodiode menjadi 150kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 150 / (1...

Configuring Swap Memory on Ubuntu Using Ansible

If we maintain a Linux machine with a low memory capacity while we are required to run an application with high memory consumption, enabling swap memory is an option. Ansible can be utilized as a helper tool to automate the creation of swap memory. A swap file can be allocated in the available storage of the machine. The swap file then can be assigned as a swap memory. Firstly, we should prepare the inventory file. The following snippet is an example, you must provide your own configuration. [server] 192.168.1.2 [server:vars] ansible_user=root ansible_ssh_private_key_file=~/.ssh/id_rsa Secondly, we need to prepare the task file that contains not only the tasks but also some variables and connection information. For instance, we set /swapfile as the name of our swap file. We also set the swap memory size to 2GB and the swappiness level to 60. - hosts: server become: true vars: swap_vars: size: 2G swappiness: 60 For simplicity, we only check the...

Free Cloud Services from UpCloud

Although I typically deploy my development environment or experimental services on UpCloud , I do not always stay updated on its announcements. Recently, I discovered that UpCloud has introduced a new plan called the Essentials plan, which enables certain cloud services to be deployed at no cost. The complimentary services are generally associated with network components or serve as the foundation for other cloud services. This feature is particularly useful when retaining foundational services, such as a load balancer, is necessary, while tearing down all services and reconfiguring the DNS and other application settings each time we temporarily clean up infrastructure to reduce costs is undesirable. When reviewing the service specifications of the cloud services in the Essentials plan, they appear to be very similar to those in the Development plan. The difference in service levels is unclear, but it could be related to hardware or resource allocation. For instance, the loa...

Deploying a Web Server on UpCloud using Terraform Modules

In my earlier post , I shared an example of deploying UpCloud infrastructure using Terraform from scratch. In this post, I want to share how to deploy the infrastructure using available Terraform modules to speed up the set-up process, especially for common use cases like preparing a web server. For instance, our need is to deploy a website with some conditions as follows. The website can be accessed through HTTPS. If the request is HTTP, it will be redirected to HTTPS. There are 2 domains, web1.yourdomain.com and web2.yourdomain.com . But, users should be redirected to "web2" if they are visiting "web1". There are 4 main modules that we need to set up the environment. Private network. It allows the load balancer to connect with the server and pass the traffic. Server. It is used to host the website. Load balancer. It includes backend and frontend configuration. Dynamic certificate. It is requ...

Manage Kubernetes Cluster using Rancher

Recently, I sought a simpler method to deploy and maintain Kubernetes clusters across various cloud providers. The goal was to use it for development purposes with the ability to manage the infrastructure and costs effortlessly. After exploring several options, I decided to experiment with Rancher. Rancher offers a comprehensive software stack for teams implementing container technology. It tackles both the operational and security hurdles associated with managing numerous Kubernetes clusters. Additionally, it equips DevOps teams with integrated tools essential for managing containerized workloads. Rancher also offers an open-source version, allowing free deployment within one's infrastructure. The Rancher platform can be deployed either as a Docker container or within a Kubernetes cluster utilizing the K3s engine. We can read the documentation on how to install Rancher on K3s using Helm . Rancher itself enables the creation and provisioning of Kubernetes clusters and ...

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