Install telnet, 텔넷 설치하기

To install telnet on a Linux system, follow the steps based on the distribution you are using. Telnet is generally available in most distribution repositories but may need to be installed manually.

1. For Debian/Ubuntu-based systems

These instructions are for distributions such as Ubuntu, Debian, and Linux Mint.

  1. Update the package list:

    sudo apt update

  2. Install the telnet package:

    sudo apt install telnet

  3. Verify the installation:

    telnet --version

2. For CentOS/RHEL-based systems

These instructions apply to CentOS, Red Hat Enterprise Linux (RHEL), and Fedora.

  1. Update the package list:

    sudo yum update

  2. Install the telnet package:

    sudo yum install telnet

  3. Verify the installation:

    telnet

3. For Fedora

On Fedora systems, use the dnf package manager.

  1. Update the package list:

    sudo dnf update

  2. Install the telnet package:

    sudo dnf install telnet

  3. Verify the installation:

    telnet --version

4. For Arch-based systems

For Arch Linux or Manjaro, use the pacman package manager.

  1. Update the package list:

    sudo pacman -Sy

  2. Install the inetutils package, which includes telnet:

    sudo pacman -S inetutils

  3. Verify the installation:

    telnet

Usage Example

To use telnet, you can simply type:

telnet <hostname or IP> <port>

For example, to connect to a web server on port 80:

telnet example.com 80

댓글

댓글 쓰기

이 블로그의 인기 게시물

The logs of the kubelet service

The logs of the kubelet service can be found depending on how the system is set up. Here are the most common locations: 1. Systemd Logs If your system uses systemd to manage services (most modern Linux distributions do), you can view the kubelet logs using journalctl : View Real-time Logs: sudo journalctl -u kubelet -f View Historical Logs: sudo journalctl -u kubelet 2. Log File on Disk On some systems, kubelet writes its logs to a file in /var/log . The exact location depends on the configuration: Common Locations : /var/log/kubelet.log /var/lib/kubelet/logs If the log file is not there, check the kubelet service configuration for custom log paths. 3. Kubernetes Configuration Flags The kubelet log location can be customized using the --log-dir or --log-file flags in the kubelet service configuration. To verify: Check the kubelet service file: cat /etc/systemd/system/kubelet .service .d / 10 -kubeadm.conf Look for logging-related flags, such as: Exec...
자세한 내용 보기

Using the MinIO API via curl

Using the MinIO API via curl is straightforward, as MinIO is compatible with Amazon S3 API, so most commands follow a similar syntax. Here’s a guide on how to use curl with the MinIO API for some common operations like uploading, downloading, and managing objects. Prerequisites Access Key and Secret Key : Obtain your MinIO Access Key and Secret Key. MinIO Endpoint : Know your MinIO server endpoint, e.g., http://localhost:9000 . Bucket : You may need an existing bucket name, or create a new one using the commands below. Authentication Header For requests to work with MinIO, you need to include authentication in the headers. MinIO uses AWS Signature Version 4 for signing requests. Common Examples 1. List Buckets To list all buckets in your MinIO account, use: curl -X GET \ - -url "http://localhost:9000/" \ - H "Authorization: AWS <AccessKey>:<Signature>" 2. Create a Bucket To create a new bucket, use: curl -X PUT \ - -url "htt...
자세한 내용 보기

Install and run an FTP server using Docker

To install and run an FTP server using Docker, follow these steps. We’ll use the popular stilliard/pure-ftpd image, which is a lightweight and widely used FTP server. Step 1: Install Docker Make sure Docker is installed on your machine. If it isn’t, install it using the instructions below: Ubuntu/Debian: sudo apt update sudo apt install docker.io -y Mac: Install Docker Desktop from Docker's website . Windows: Install Docker Desktop from Docker's website . Verify Docker is installed: docker --version Step 2: Pull the FTP Server Docker Image Use the stilliard/pure-ftpd image, which is a simple and effective FTP server. docker pull stilliard/ pure -ftpd Step 3: Run the FTP Server Run the FTP server container using the following command: docker run -d --name ftp-server \ - p 21 : 21 -p 30000 - 30009 : 30000 - 30009 \ - e FTP_USER_NAME=testuser \ - e FTP_USER_PASS=testpass \ - e FTP_USER_HOME= /home/testuser \ stilliard/pure-ftpd Explanation...
자세한 내용 보기

Screenshot of a web page using Puppeteer with a specific browser width, 웹페이지 스크린샷

To get a screenshot of a web page using Puppeteer with a specific browser width, you can follow these steps: Install Puppeteer by running the command npm install puppeteer in your project directory. Require Puppeteer in your Node.js script: const puppeteer = require( 'puppeteer' ); Launch a new browser instance with the desired viewport size: const browser = await puppeteer.launch({ defaultViewport: { width : 1280 , height : 720 , }, }); Create a new page in the browser: const page = await browser. newPage () ; Navigate to the desired URL: await page. goto ( 'https://example.com' ); Take a screenshot of the page: await page .screenshot ({ path : 'screenshot.png' }); Close the browser instance: await browser.close() ; Here's the complete code: const puppeteer = require ( 'puppeteer' ); ( async ( ) => { const browser = await puppeteer.launch({ defaultViewport : { width : 1280 , ...
자세한 내용 보기

CDPEvents in puppeteer

In Puppeteer , CDPEvents refers to events emitted by the Chrome DevTools Protocol (CDP) . Puppeteer leverages CDP to interact with and control a Chromium-based browser. CDP provides detailed, low-level access to browser internals, such as network traffic, console logs, page lifecycle events, and more. You can listen to these CDP events through Puppeteer’s API to monitor or intercept browser activity. How to Listen for CDP Events in Puppeteer Enable the Required CDP Domain: Some events require enabling a particular domain (e.g., 'Network' , 'Page' , 'Runtime' ). Use page._client() to Access the CDP Session: Although it’s a bit lower-level, Puppeteer allows access to DevTools through the page._client() API. Example: Listening for Network Requests This example demonstrates how to intercept and log network requests using CDP. const puppeteer = require( 'puppeteer' ); ( async () => { const browser = await puppeteer.launch({ headless...
자세한 내용 보기

Using venv in Python

Using venv in Python allows you to create a virtual environment, which is an isolated environment to manage dependencies for a specific project. Here's how you can use it step by step: 1. Create a Virtual Environment Open your terminal or command prompt. Navigate to the folder where you want to create the virtual environment. Run the following command: python -m venv myenv Replace myenv with the name you want for your virtual environment. This will create a directory named myenv containing the virtual environment. 2. Activate the Virtual Environment Activation depends on your operating system: On Windows : myenv \S cripts \a ctivate On macOS/Linux : source myenv /bin/ activate After activation, your terminal prompt will change, showing the name of the virtual environment (e.g., (myenv) ). 3. Install Dependencies With the virtual environment activated, you can now install packages using pip : pip install package _n ame For example: pip install req...
자세한 내용 보기

To switch to a specific tag in a Git repository

To switch to a specific tag in a Git repository, you can use the git checkout or git switch command. Here's how you can do it: 1. List Available Tags First, you may want to see a list of all available tags in the repository: git tag 2. Checkout a Specific Tag Once you know the tag you want to switch to, you can use either git checkout or git switch (if you're using a newer version of Git, which recommends git switch for checking out branches). Using git checkout : git checkout <tag- name > Using git switch (recommended for newer versions of Git): git switch -- detach <tag- name > The --detach flag is necessary because tags are not branches; they are just pointers to specific commits. Using --detach makes your HEAD point to the tag without modifying any branch. 3. Verify the Checkout After switching to the tag, verify that you're on the correct commit: git status This will show the tag you're currently on (you'll see somethi...
자세한 내용 보기

Delete topic on Kafka, 카프카 토픽 삭제하기

To delete a topic in Kafka, you need to ensure that the Kafka cluster is properly configured to allow topic deletions and then execute the deletion command. Here's a step-by-step guide on how to do this: 1. Enable Topic Deletion in Kafka (if not already enabled) By default, Kafka does not always enable topic deletion. You need to ensure that the Kafka broker has the following setting in the configuration file ( server.properties ): delete .topic .enable =true This setting allows topics to be deleted. If it is set to false , topic deletion will not work. You must restart the Kafka broker after making this change. 2. Delete a Topic Using Kafka Command-Line Tools Once topic deletion is enabled, you can delete a Kafka topic using the Kafka command-line tool ( kafka-topics.sh or kafka-topics.bat for Windows). Example: $ kafka-topics. sh --bootstrap-server localhos t:9092 -- delete --topic <topic_name> Replace <topic_name> with the actual name of the topic you...
자세한 내용 보기

NodePort vs ClusterIP on Kubernetes, 쿠버네티스 서비스

Kubernetes(k8s)에 대해 전문가 수준의 이해를 돕기 위해 몇 가지 중요한 개념을 설명드리겠습니다. Kubernetes는 컨테이너화된 애플리케이션을 자동화하고 관리하는 오픈 소스 플랫폼입니다. 다음은 Kubernetes 전문가가 이해해야 할 핵심 주제들입니다. 1. Kubernetes의 핵심 컴포넌트 Pod : Kubernetes의 기본 배포 단위로, 하나 이상의 컨테이너를 포함합니다. Node : 애플리케이션이 실행되는 물리적 또는 가상 머신입니다. Cluster : 여러 노드가 모인 집합으로, 전체적으로 애플리케이션을 실행하는 단위입니다. Control Plane : Kubernetes 클러스터를 관리하는 중앙 관리 엔티티입니다. 주요 구성 Kubernetes에서 NodePort 와 ClusterIP 를 동시에 지원하는 설정을 만들기 위해서는 Kubernetes Service 를 사용하는 것이 핵심입니다. NodePort 는 클러스터 외부에서 접근할 수 있도록 하며, ClusterIP 는 클러스터 내부에서 접근할 수 있게 해줍니다. Kubernetes의 Service는 기본적으로 하나의 방식으로 트래픽을 전달하지만, 하나의 애플리케이션에 대해 여러 방식으로 접근을 제공하는 방법은 가능합니다. 여기에서는 하나의 Service를 NodePort 와 ClusterIP 로 동시에 사용하는 설정을 구성하는 방법을 설명드리겠습니다. 설정 방법 NodePort와 ClusterIP를 동시에 사용하는 방식 NodePort는 외부에서 접근할 수 있는 고정된 포트로, ClusterIP는 내부 클러스터에서의 접근을 위해 사용됩니다. 두 가지 방식을 동시에 사용하려면 기본적으로 LoadBalancer 타입의 Service를 설정하고, externalTrafficPolicy: Local 을 통해 두 방식의 트래픽을 모두 처리할 수 있도록 합니다. 예시 YAML 파일 apiVersion: v1 kind: Service metadata:...
자세한 내용 보기