Creating a Self-Signed SSL Certificate

A self-signed SSL Certificate can be used if you want to make a secure connection to a server by encrypting the data like the HTTPS connection. We can utilize OpenSSL to generate the key and certificate. We can run $ sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /path/to/yourkey.key -out /path/to/yourcert.crt to generate the key and certificate files.

Some important parameters are as follows:

req: This specifies a subcommand for X.509 certificate signing request (CSR) management. X.509 is a public key infrastructure standard that SSL adheres to for its key and certificate management. Since we are wanting to create a new X.509 certificate, this is what we want.

-x509: This option specifies that we want to make a self-signed certificate file instead of generating a certificate request.

-nodes: This option tells OpenSSL that we do not wish to secure our key file with a passphrase. Having a password-protected key file would get in the way of Apache starting automatically as we would have to enter the password every time the service restarts.

-days 365: This specifies that the certificate we are creating will be valid for one year.

-newkey rsa:2048: This option will create the certificate request and a new private key at the same time. This is necessary since we didn't create a private key in advance. The rsa:2048 tells OpenSSL to generate an RSA key that is 2048 bits long.

Comments

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 / (150+10) x Vcc V- = (150/160) x 5

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 exi

Resize VirtualBox LVM Storage

VirtualBox is a free solution to host virtual machines on your computer. It provides configuration options for many components on our machine such as memory, storage, networking, etc. It also allows us to resize our machine storage after its operating system is installed. LVM is a volume manager in a Linux platform that helps us to allocate partitions in the system and configure the storage size that will be utilized for a specific volume group. There are some points to be noticed when we work with LVM on VirtualBox to resize our storage. These are some steps that need to be performed. 1. Stop your machine before resizing the storage. 2. Set new storage size using GUI by selecting " File > Virtual Media Manager > Properties " then find the desired virtual hard disk name that will be resized. OR , by running a CLI program located in " Program Files\Oracle\VirtualBox\VBoxManage.exe ". cd "/c/Program Files/Oracle/VirtualBox" ./VBoxManage.exe list

Installing VSCode Server Manually on Ubuntu

I've ever gotten stuck on updating the VSCode server on my remote server because of an unstable connection between my remote server and visualstudio.com that host the updated server source codes. The download and update process failed over and over so I couldn't remotely access my remote files through VSCode. The solution is by downloading the server source codes through a host with a stable connection which in my case I downloaded from a cloud VPS server. Then I transfer the downloaded source codes as a compressed file to my remote server through SCP. Once the file had been on my remote sever, I extracted them and align the configuration. The more detailed steps are as follows. First, we should get the commit ID of our current VSCode application by clicking on the About option on the Help menu. The commit ID is a hexadecimal number like 92da9481c0904c6adfe372c12da3b7748d74bdcb . Then we can download the compressed server source codes as a single file from the host.

Generate API Documentation Using Swagger Module in NestJS

Swagger provides us a standard to generate API documentation based on the Open API specification. If we use NestJS for building our API providers, we can utilize a tool provided by NestJS in the @nestjs/swagger module to generate the documentation automatically in the built time. This module also requires the swagger-ui-express module if we use Express as the NestJS base HTTP handler. Set Swagger configuration First, we need to define Swagger options and instantiate the documentation provider on the main.ts file. import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger'; // sample application instance const app = await NestFactory.create(AppModule); // setup Swagger options const options = new DocumentBuilder() .setTitle('Coffee') .setVersion('1.0') .setDescription('Learn NestJS with coffee') .build(); // build the document const document = SwaggerModule.createDocument(app, options); // provide an endpoint

How To Use Protocol Buffer in Javascript

We have understood a few advantages of protocol buffer like what I've explained in my other post . Now, let's look at how we can implement it in our code. The "transpiler" tool, named protoc , supports the generation of a helper class for managing the object instance in a variety of programming languages. In this post, we use Javascript as an example and run in a Linux environment. Preparation Before we develop our code, we should install protoc for generating the helper class. Download protoc binary from the release page . Extract the content and store the directories ( bin and includes ) in /usr/local directory so that the executable binary can be accessed directly. Run protoc --help to check its manual. Install a required dependency globally to enable protoc to generate the Javascript files by running: npm i -g protoc-gen-js . Create a proto file First, we should create an empty directory

LUKI NOTES

Search This Blog