Deploy Redmine Project Management using Docker

10/18/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 Deploy Redmine Project Management
2 Conclusion

#Introduction

In this tutorial, How to Deploy Redmine Project Management using Docker Compose. Redmine is an Open Source project management you can install on your LAN or Cloud host.

You need to install Docker and Docker-Compose on Ubuntu.

Deploy Redmine Project Management

Create the Dockerfile

mkdir ~/redmine
cd ~/redmine
nano Dockerfile

paste the following content:

FROM redmine:5.0.3

RUN apt-get update

Save and close the file.

Create the docker-compose.yml file

nano docker-compose.yml

paste the following content:

version: '3.3'

services:

   postgres:

     image: postgres:10

     volumes:

       - ./storage/postgresql-data:/var/lib/postgresql/data

     environment:

       POSTGRES_PASSWORD: "POSTGRES12345"

       POSTGRES_DB: "redmine"

       PGDATA: "/var/lib/postgresql/data"

     restart: always

   redmine:

     build:

       context: .

     image: redmine:custom

     ports:

       - 80:3000

     volumes:

       - ./storage/docker_redmine-plugins:/usr/src/redmine/plugins

       - ./storage/docker_redmine-themes:/usr/src/redmine/public/themes

       - ./storage/docker_redmine-data:/usr/src/redmine/files

     environment:

       REDMINE_DB_POSTGRES: "postgres"

       REDMINE_DB_USERNAME: "postgres"

       REDMINE_DB_PASSWORD: "POSTGRES12345"

       REDMINE_DB_DATABASE: "redmine"

       REDMINE_SECRET_KEY_BASE: "…"

     restart: always

The deploy the container

docker-compose up -d

Access Redmine

Open your web browser to http://SERVER

Conclusion

You Deploy Redmine Project Management using Docker. I hope this will be helpful. Thank you for reading the DevopsRoles page!

Docker

Manage Docker Containers with Yacht

09/19/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 Manage Docker Containers with Yacht
- 1.1 Pull the Yacht docker image
2 Logging into Yacht
3 Conclusion

#Introduction

In this tutorial, How to Manage Docker Containers with Yacht. The yacht is GUI to Manage your Docker containers.

You can deploy, modify and manage containers with Yacht. I will set up Yacht on the Linux system.

Manage Docker Containers with Yacht

First, You need to Installed Docker on Linux here.

Pull the Yacht docker image

I will pull the Yacht docker image from DockerHub. Log in to the server using the root account.

sudo su -

Create volume to hold all of the Yacht data on the server.

docker volume create yacht

Docker will deploy the image as a container on your system with the command below

docker run -d -p 8000:8000 -v /var/run/docker.sock:/var/run/docker.sock -v yacht:/config selfhostedpro/yacht

After installing Yacht, you can access it via web UI in any browser.

http://IP-your-server:8000

Logging into Yacht

the default password and username to log into Yacht. admin@yacht.local/pass

Dashboard Yacht

View Applications

Manage volumes

Manage Network

Manage images by Yacht

Conclusion

You have Manage Docker Containers with Yacht. I hope this will be helpful. Thank you for reading the DevopsRoles page!

Linux

How to install Gitea repository in Ubuntu

09/09/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Understanding Gitea
- 2.1 Why Choose Gitea?
3 Prerequisites
4 Install Gitea repository in Ubuntu
- 4.1 Install the necessary dependencies
- 4.2 Create a database and user
5 Install Gitea repository
- 5.1 Create a systemd service file for Gitea.
6 Access the Gitea web-based installer
7 Conclusion

Introduction

In this tutorial, How to install Gitea repository in Ubuntu.

Understanding Gitea

Gitea is a web-based Git repository management tool, similar to GitHub, GitLab, and Bitbucket. It is a self-hosted, open-source software that allows developers to create and manage Git repositories, as well as collaborate with others on software development projects.
With Gitea, you can create your own private Git repositories, manage access control and permissions for users and teams, and track issues and bugs with an integrated issue tracker. It also supports pull requests, code reviews, and continuous integration and deployment with built-in integrations for popular tools like Jenkins and Travis CI.
It is written in Go, and it’s lightweight and easy to set up and run.

Why Choose Gitea?

Lightweight: Gitea is very resource-efficient.
Open Source: It is free to use and modify.
Feature-Rich: Offers essential Git features along with additional tools like issue tracking and code review.
Easy to Install: The setup process is straightforward, making it accessible even for beginners.

Prerequisites

Before you begin, ensure you have the following:

An Ubuntu server instance with sudo privileges.
A basic understanding of terminal commands.

Install Gitea repository in Ubuntu

Install the necessary dependencies

sudo apt-get install wget get mariadb-server -y

After the installation, secure the database server as command below:

sudo mysql_secure_installation

Create a database and user

sudo mysql -u root -p

Create the database

CREATE DATABASE gitea;
GRANT ALL PRIVILEGES ON gitea.* TO 'gitea'@'localhost' IDENTIFIED BY "your_password";
FLUSH PRIVILEGES;
exit

Install Gitea repository

Download and copy to /usr/local/bin

sudo wget -O /usr/local/bin/gitea https://dl.gitea.io/gitea/1.17.1/gitea-1.17.1-linux-amd64

Change the permissions

sudo chmod +x /usr/local/bin/gitea

Create a new system user for running Gitea:

sudo adduser --system --shell /bin/bash --gecos 'Git Version Control' --group --disabled-password --home /home/git git

Create the folder and change the permission

sudo mkdir -pv /var/lib/gitea/{custom,data,log}
sudo chown -Rv git:git /var/lib/gitea
sudo chmod -Rv 750 /var/lib/gitea
sudo mkdir -v /etc/gitea
sudo chown -Rv root:git /etc/gitea
sudo chmod -Rv 770 /etc/gitea

Create a systemd service file for Gitea.

Create a new systemd service file for Gitea by running the following command:

sudo nano /etc/systemd/system/gitea.service

Paste the following configuration into the service file:

[Unit]
Description=Gitea
After=syslog.target
After=network.target

[Service]
RestartSec=3s
Type=simple
User=git
Group=git
WorkingDirectory=/var/lib/gitea/

ExecStart=/usr/local/bin/gitea web --config /etc/gitea/app.ini
Restart=always
Environment=USER=git HOME=/home/git GITEA_WORK_DIR=/var/lib/gitea

[Install]
WantedBy=multi-user.target

Save and close the file.

Start and enable the Gitea service by running the following commands:

sudo systemctl start gitea
sudo systemctl enable --now gitea

Access the Gitea web-based installer

Open a browser and point it to http://YOUR_SERVER:3000

Conclusion

You have to install Gitea repository in Ubuntu. I hope this will be helpful. Thank you for reading the DevopsRoles page!

Docker

Set A Memory Limit For Docker Containers

08/30/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 How to Set A Memory Limit For Docker Containers
2 Conclusion

#Introduction

In this tutorial, How to Set A Memory Limit For Docker Containers. Docker container defaults to running without any resource constraints.

In production, each container will set a memory limit to prevent runaway resource consumption.

How to Set A Memory Limit For Docker Containers

You set hard and soft memory limits on individual containers.

Hard memory limits

Hard limit on virtual memory, any worker exceeding the limit will be immediately killed without waiting for the end of the current request processing.

Soft memory limits

Maximum allowed virtual memory per worker.

How to setting hard memory limits

Set by docker run command with “-m” or “–memory” flag. For example, set value 2g

$ docker run --memory=2g devopsroles-app:latest

How to setting soft memory limits

Soft memory limits are set with the “–memory-reservation” flag. For example, set the value to 512m of reserved memory. It will always stop if usage exceeds 512MB.

$ docker run --memory=512m --memory-reservation=256m devopsroles:latest

setting Swap Memory

The “--memory-swap" flag controls the amount of swap space available in conjunction with the “–memory” flag. For example, Container has access to 1000MB of memory of which 512MB is physical RAM. The remaining 488MB is swap space stored on disk.

$ docker run --memory=512m --memory-swap=1000m devopsroles:latest

How to disable Out-Of-Memory process skills.

The result in the container stopping with the error code is 137. Use “–oom-kill-disable” with your docker run command to disable this behavior.

Conclusion

You have Set A Memory Limit For Docker Containers. I hope this will your helpful. Thank you for reading the DevopsRoles page!

Linux

How to find large files Linux

08/18/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Use find command line
3 Use the du command line
4 Linux combines find and du command
5 Conclusion

Introduction

How to Find large files Linux. To find large files in Linux, you can use the find command along with the du (disk usage) command.

In this blog post, we will explore a simple yet powerful method to identify and locate large files in Linux using the command line.

Use find command line

The find command line can use to search any files inside a Linux Filesystem.

Find the command line inside your current working directory as the command below:

find . -type f

Filter with a minimum size of 10MB

find . -type f -size +10M

To search the entire filesystem to find the largest file.

sudo find / -xdev -type f -size +10M

Note: “-xdev flag” won’t scan other mounted filesystems in your Linux Server.

To scan all the mounted drives along with your primary filesystem

sudo find / -type f -size +10M

Find Large Unused Files: These have not been modified for more than 30 days and have a file size of at least 10 MB.

sudo find / -xdev -mtime +30 -type f -size +10M

Use the du command line

the du command to estimate file sizes in Linux. And how to find large files in Linux

List the files along with directory sizes recursively

du -ah

combined with the command sort command to sort the files in descending order. use the blocksize operator -B along with a unit of your choice. If you want to convert the sizes in MB, use unit M as a block size.

du -aBM | sort -nr

To find the largest 15 files in your entire filesystem

du / -aBM | sort -nr | head -n 15

Linux combines find and du command

find /path/to/directory -type f -size +100M -exec du -sh {} \; 2>/dev/null | sort -rh | head -n 10

Let’s break it down:

find /path/to/directory: Replace /path/to/directory with the actual directory path where you want to start the search for large files.
-type f: Specifies that you’re looking for regular files.
-size +100M: Filters files that are larger than 100 megabytes. Adjust this value as per your requirements.
-exec du -sh {} \;: Executes the du -sh command on each found file to display its size in a human-readable format.
2>/dev/null: Redirects any error messages to /dev/null to suppress them.
sort -rh: Sorts the output in a reverse human-readable format to display the largest files first.
head -n 10: Displays only the first 10 lines of the output, which will be the largest files.

Conclusion

Effectively managing disk space is crucial for maintaining system performance and organization. With the find command in Linux, locating large files becomes a straightforward process. By following the steps outlined in this blog post, you can easily identify and manage large files, reclaiming valuable disk space on your Linux system.

You have to find large files in Linux. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Linux

How to use bash create file in Linux

08/15/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 How to use Bash to create a file
- 2.1 Bash create file: A Guide to Using the Touch Command
- 2.2 shell command
3 Conclusion

Introduction

This tutorial is all about using bash create file in Linux in the terminal. Guess what? It’s super easy! Bash has this neat and efficient command called “touch” that makes creating files a breeze. So, let’s dive in and discover how to use the touch command to create new files in Bash.

Alright, so what’s the deal with this “touch” command? Well, it’s like a magic wand for your terminal. With just a simple touch command, you can conjure up new files effortlessly. No need to go through complicated steps – Bash keeps it straightforward. In this tutorial, we’re going to break down the touch command and explore how it turns your terminal into a file-creating wizard.

Creating files in Bash doesn’t have to be a puzzle. With the trusty touch command, you’ll be crafting files like a pro in no time. This tutorial is your guide to mastering the art of file creation in Bash, so get ready to unleash the power of the touch command and make your terminal work wonders!

How to use Bash to create a file

Bash create file: A Guide to Using the Touch Command

The touch command to create an empty text file with foo.txt

The touch command in Bash is primarily used to update the access and modification timestamps of files. However, it can also be used to create a new file if it doesn’t already exist.

To create a new file using the touch command, follow this syntax:

$ touch foo.bar
$ > foo.bar

To make a text file using the cat command line on Linux. press ctrl+c to quit and save the file.

$ cat > foo.txt

shell command

$ echo 'This is my blog: devopsroles.com' > foo.txt

Append text to an existing file

$ echo 'yet another line: huuphan.com' >> foo.txt

To create a text file, you can use the vi or vim commands in your terminal. These tools are powerful editors for crafting text documents. Simply type vi or vim followed by the desired filename and press Enter. This will open an editor where you can write and edit your text. To begin typing, press i to enter insert mode. When you’re finished, press the Esc key to exit insert mode.

To save your work, type :w and press Enter. To close the editor, type :q, or you can save and exit at the same time by typing :wq. With these simple steps, you’ve successfully created your text file!

Conclusion

You have to use the Bash create file command terminal. Creating a new file in Bash is a straightforward process with the help of the touch command. Its simplicity and efficiency make it a popular choice for generating empty files. By using the touch command and providing the desired filename, you can quickly create new files in your Bash scripts or command-line operations. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Linux

How to Password Protect Files on Linux : A Complete Guide

08/07/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 How to Password Protect Files on Linux
3 Conclusion

Introduction

In this tutorial, you’ll learn how to password protect files on Linux to ensure they remain secure from unauthorized access. Various methods are available for this purpose, each providing different levels of security. Here are a few techniques to help you safeguard your files and folders with strong passwords.

Using tools like zip and gpg, you can encrypt your files effectively. zip allows you to compress and password protect files, while gpg offers robust encryption options. Both methods are straightforward and enhance the security of your sensitive data on Linux systems.

How to Password Protect Files on Linux

Encrypt a File with GnuPG

I use gpg command to encrypt a file. GnuPG is a free Linux program that supports multiple encryptions for file encryption.

1. Open the terminal

2. Run the following command line to encrypt your file.

gpg -c your_file

GnuPG will create an encrypted file with .gpg extension in your current working folder.

The result is the picture below:

To access it, you’ll need to decrypt it. For this, run the following command

gpg your_file.gpg

The result is the picture below:

other encryption algorithms, first, check the supported ones by running:

For example, you specify the desired algorithm as a command below

gpg -c --cipher-algo algorithm_name your_file

using the zip command to Encrypt a File

the zip command is another CLI utility that password-protect files on Linux. it is pre-installed on all Linux distros.

zip --password your_password archive_file.zip file1 file2

you replace your_passowrd with the password you want to use to encrypt the archive.

Unzip the archive and enter your password. you can run the command below:

unzip archive_file.zip

Encrypt a File Using mcrypt

list out all the supported encryption algorithms

mcrypt --list

encrypt filename

mcrypt -a algorithm_name filename

If you wish to open this file, you’ll need to decrypt it as the command below:

mcrypt -d filename.nc

Conclusion

By following this tutorial, you now know how to password protect files on Linux, enhancing your data security. Always choose a strong, unique password when prompted and consider using a password manager to keep your passwords safe and easily accessible. Implementing these methods helps prevent unauthorized access and ensures your sensitive information remains protected. Thank you for reading the DevopsRoles page and I hope you found this information helpful. Stay secure!

Linux

Fixing the “Ubuntu Repository No Longer Has a Release” Issue

08/05/2022 HuuPV 2 Comments

Table of Contents

1 Introduction
2 Ubuntu repository no longer has a Release fixed
3 Via Youtube
4 Conclusion

Introduction

In this tutorial, How to fix the Ubuntu repository no longer has a Release.

Ubuntu, a widely used Linux distribution, relies on repositories to provide software packages and updates. Occasionally, you might encounter the error message “Ubuntu repository no longer has a release,” indicating that the repository you’re trying to access is unavailable or unsupported. This article delves into the reasons behind this issue and offers potential solutions to address it effectively.

Today, I am installing Nginx, But suddenly one day you use this command and get the following error:

vagrant@controller:~$ sudo apt install nginx -y
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  libnginx-mod-http-geoip2 libnginx-mod-http-image-filter libnginx-mod-http-xslt-filter libnginx-mod-mail
  libnginx-mod-stream libnginx-mod-stream-geoip2 nginx-common nginx-core
Suggested packages:
  fcgiwrap nginx-doc ssl-cert
The following NEW packages will be installed:
  libnginx-mod-http-geoip2 libnginx-mod-http-image-filter libnginx-mod-http-xslt-filter libnginx-mod-mail
  libnginx-mod-stream libnginx-mod-stream-geoip2 nginx nginx-common nginx-core
0 upgraded, 9 newly installed, 0 to remove and 0 not upgraded.
Need to get 700 kB of archives.
After this operation, 2386 kB of additional disk space will be used.
Ign:1 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 nginx-common all 1.18.0-6ubuntu11.1
Ign:2 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-geoip2 amd64 1.18.0-6ubuntu11.1
Ign:3 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-image-filter amd64 1.18.0-6ubuntu11.1Ign:4 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-xslt-filter amd64 1.18.0-6ubuntu11.1
Ign:5 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-mail amd64 1.18.0-6ubuntu11.1
Ign:6 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-stream amd64 1.18.0-6ubuntu11.1
Ign:7 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-stream-geoip2 amd64 1.18.0-6ubuntu11.1
Ign:8 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 nginx-core amd64 1.18.0-6ubuntu11.1
Ign:9 http://archive.ubuntu.com/ubuntu impish-updates/main amd64 nginx amd64 1.18.0-6ubuntu11.1
Err:1 http://security.ubuntu.com/ubuntu impish-updates/main amd64 nginx-common all 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
Err:2 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-geoip2 amd64 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
Err:3 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-image-filter amd64 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
Err:4 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-http-xslt-filter amd64 1.18.0-6ubuntu11.1  404  Not Found [IP: 91.189.91.39 80]
Err:5 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-mail amd64 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
Err:6 http://security.ubuntu.com/ubuntu impish-updates/main amd64 libnginx-mod-stream amd64 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
  404  Not Found [IP: 91.189.91.39 80]
Err:9 http://security.ubuntu.com/ubuntu impish-updates/main amd64 nginx amd64 1.18.0-6ubuntu11.1
  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/nginx-common_1.18.0-6ubuntu11.1_all.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-http-geoip2_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-http-image-filter_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-http-xslt-filter_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-mail_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-stream_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/libnginx-mod-stream-geoip2_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/nginx-core_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/n/nginx/nginx_1.18.0-6ubuntu11.1_amd64.deb  404  Not Found [IP: 91.189.91.39 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Cause: older releases of Ubuntu moved to a new host.

If you encounter an issue where the Ubuntu repository no longer has a “Release” file, it could be due to a temporary problem with the repository or a misconfiguration on your system. Here are a few steps you can take to troubleshoot and potentially resolve the issue:

Ubuntu repository no longer has a Release fixed

Step 1. Backup file sources.list

cp /etc/apt/sources.list /etc/apt/sources.list.bak

Step 2. Replace the links with the new repository address.

sudo sed -i -re 's/([a-z]{2}.)?archive.ubuntu.com|security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list

Step 3. Update OS after steps 1 and step 2.

sudo apt-get update && sudo apt-get dist-upgrade

At this point, when you see that command 3 has run successfully, you can completely select Y to continue the update process for your Ubuntu server. Or select N to cancel the update process.

As a result, the fixed repository no longer has a Release file on Ubuntu Server. For example, I select Y.

root@controller:~# sudo apt-get update && sudo apt-get dist-upgrade
Get:1 http://old-releases.ubuntu.com/ubuntu impish InRelease [270 kB]
Hit:2 https://apache.jfrog.io/artifactory/couchdb-deb focal InRelease
Get:3 http://old-releases.ubuntu.com/ubuntu impish-updates InRelease [115 kB]
Get:4 http://old-releases.ubuntu.com/ubuntu impish-backports InRelease [101 kB]
Get:5 http://old-releases.ubuntu.com/ubuntu impish-security InRelease [110 kB]
Get:6 http://old-releases.ubuntu.com/ubuntu impish/main amd64 Packages [1396 kB]
Get:7 http://old-releases.ubuntu.com/ubuntu impish/main Translation-en [511 kB]
Get:8 http://old-releases.ubuntu.com/ubuntu impish/main amd64 c-n-f Metadata [29.8 kB]
Get:9 http://old-releases.ubuntu.com/ubuntu impish/restricted amd64 Packages [82.2 kB]
Get:44 http://old-releases.ubuntu.com/ubuntu impish-security/universe amd64 c-n-f Metadata [5396 B]
Get:45 http://old-releases.ubuntu.com/ubuntu impish-security/multiverse amd64 Packages [4776 B]
Get:46 http://old-releases.ubuntu.com/ubuntu impish-security/multiverse Translation-en [988 B]
Get:47 http://old-releases.ubuntu.com/ubuntu impish-security/multiverse amd64 c-n-f Metadata [228 B]
Fetched 23.4 MB in 1min 34s (248 kB/s)
Reading package lists... Done
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  git git-man libpython3.9 libpython3.9-minimal libpython3.9-stdlib python3-distupgrade python3.9 python3.9-minimal
  ubuntu-release-upgrader-core
9 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
7 standard security updates
Need to get 11.1 MB of archives.
After this operation, 24.6 kB disk space will be freed.
Do you want to continue? [Y/n] y
Get:1 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 python3.9 amd64 3.9.7-2ubuntu0.1 [433 kB]
Get:2 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 libpython3.9 amd64 3.9.7-2ubuntu0.1 [1897 kB]
Get:3 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 libpython3.9-stdlib amd64 3.9.7-2ubuntu0.1 [1807 kB]
Get:4 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 python3.9-minimal amd64 3.9.7-2ubuntu0.1 [2058 kB]
Get:5 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 libpython3.9-minimal amd64 3.9.7-2ubuntu0.1 [783 kB]
Get:6 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 ubuntu-release-upgrader-core all 1:21.10.10 [25.5 kB]
Get:7 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 python3-distupgrade all 1:21.10.10 [104 kB]
Get:8 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 git-man all 1:2.32.0-1ubuntu1.3 [943 kB]
Get:9 http://old-releases.ubuntu.com/ubuntu impish-updates/main amd64 git amd64 1:2.32.0-1ubuntu1.3 [3038 kB]
Fetched 11.1 MB in 50s (221 kB/s)
(Reading database ... 99174 files and directories currently installed.)
Preparing to unpack .../0-python3.9_3.9.7-2ubuntu0.1_amd64.deb ...
Unpacking python3.9 (3.9.7-2ubuntu0.1) over (3.9.7-2build1) ...
Preparing to unpack .../1-libpython3.9_3.9.7-2ubuntu0.1_amd64.deb ...
Unpacking libpython3.9:amd64 (3.9.7-2ubuntu0.1) over (3.9.7-2build1) ...
Preparing to unpack .../2-libpython3.9-stdlib_3.9.7-2ubuntu0.1_amd64.deb ...
Unpacking libpython3.9-stdlib:amd64 (3.9.7-2ubuntu0.1) over (3.9.7-2build1) ...
Preparing to unpack .../3-python3.9-minimal_3.9.7-2ubuntu0.1_amd64.deb ...
Unpacking python3.9-minimal (3.9.7-2ubuntu0.1) over (3.9.7-2build1) ...
Preparing to unpack .../4-libpython3.9-minimal_3.9.7-2ubuntu0.1_amd64.deb ...
Unpacking libpython3.9-minimal:amd64 (3.9.7-2ubuntu0.1) over (3.9.7-2build1) ...
Preparing to unpack .../5-ubuntu-release-upgrader-core_1%3a21.10.10_all.deb ...
Unpacking ubuntu-release-upgrader-core (1:21.10.10) over (1:21.10.9) ...
Preparing to unpack .../6-python3-distupgrade_1%3a21.10.10_all.deb ...
Unpacking python3-distupgrade (1:21.10.10) over (1:21.10.9) ...
Preparing to unpack .../7-git-man_1%3a2.32.0-1ubuntu1.3_all.deb ...
Unpacking git-man (1:2.32.0-1ubuntu1.3) over (1:2.32.0-1ubuntu1.2) ...
Preparing to unpack .../8-git_1%3a2.32.0-1ubuntu1.3_amd64.deb ...
Unpacking git (1:2.32.0-1ubuntu1.3) over (1:2.32.0-1ubuntu1.2) ...
Setting up libpython3.9-minimal:amd64 (3.9.7-2ubuntu0.1) ...
Setting up python3-distupgrade (1:21.10.10) ...
Setting up ubuntu-release-upgrader-core (1:21.10.10) ...
Setting up git-man (1:2.32.0-1ubuntu1.3) ...
Setting up python3.9-minimal (3.9.7-2ubuntu0.1) ...
Setting up libpython3.9-stdlib:amd64 (3.9.7-2ubuntu0.1) ...
Setting up libpython3.9:amd64 (3.9.7-2ubuntu0.1) ...
Setting up git (1:2.32.0-1ubuntu1.3) ...
Setting up python3.9 (3.9.7-2ubuntu0.1) ...
Processing triggers for man-db (2.9.4-2) ...
Processing triggers for libc-bin (2.34-0ubuntu3.2) ...
Scanning processes...
Scanning candidates...
Scanning linux images...

Running kernel seems to be up-to-date.

Restarting services...
Service restarts being deferred:
 systemctl restart networkd-dispatcher.service
 systemctl restart unattended-upgrades.service

No containers need to be restarted.

No user sessions are running outdated binaries.

Via Youtube

Conclusion

By understanding the potential causes and implementing the solutions provided in this article, you can address the issue and restore the functionality of your package manager.

Whether it’s removing unsupported repositories, updating URLs, ensuring network connectivity, or waiting for temporary issues to be resolved, these steps will help you navigate and resolve the error efficiently.

You have a fixed repository no longer has a Release file on Ubuntu. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Linux

Linux Systemd Cheat Sheet Useful

07/26/2022 HuuPV Leave a comment

Table of Contents

1 Introduction
2 Systemd Cheat Sheet in Linux
3 Logs with systemd
4 Introspection with systemd
5 Services
6 Targets (runlevels)
7 FAQ Section
8 External Resources
9 Conclusion

Introduction

In this tutorial, I write about the Systemd cheat sheet useful in Linux. Systemd provides a system and service that runs at PID 1. It tracks logged-in users and runs containers virtual machines and more.

The Linux Systemd Cheat Sheet is a handy guide that provides quick and easy-to-understand information about Systemd. Systemd is a system and service manager for Linux operating systems, and this cheat sheet is designed to help users navigate and utilize its features efficiently.

Whether you’re a beginner or an experienced Linux user, this cheat sheet covers essential commands and functions related to Systemd. From starting and stopping services to managing system processes, the cheat sheet is a valuable resource for anyone looking to streamline their Linux system management tasks.

With the Linux Systemd Cheat Sheet, you can quickly reference key Systemd commands, making it easier to troubleshoot issues, configure services, and optimize system performance. This user-friendly guide aims to empower Linux users with the knowledge they need to navigate Systemd effectively, ensuring a smoother and more efficient system administration experience.

Systemd Cheat Sheet in Linux

Logs with systemd

The content	Command Line
View all system logs	journalctl
List boot numbers	journalctl –list-boots
View logs for unit ssh	journalctl –unit ssh
View system logs from the most recent	journalctl -xe

For example the picture below

Introspection with systemd

The content	Command Line
show unit file settings	systemctl show sshd
Show contents of the unit file	systemctl cat sshd
Show whether the unit is active	systemctl is-active sshd
Show whether the unit has failed	systemctl is-failed sshd
Edit unit file configuration	sudo systemctl edit sshd
Restart daemon	sudo systemctl daemon-reload

Services

The content	Command Line
Start service nginx	systemctl start nginx
Stop service nginx	systemctl stop nginx
Show status of service nginx	systemctl status nginx
Start nginx now and at system startup	systemctl enable –now nginx
At system startup, start (enable) nginx	systemctl enable nginx
At system startup, do not start nginx	systemctl disable nginx
Show whether service nginx is enabled	systemctl is-enabled nginx
Prevent service from starting (mask)	systemctl mask nginx
Unmask service, allowing it to be started	systemctl unmask nginx
List all available services	systemctl list-unit-files –-type service

For example as below

Targets (runlevels)

Targets, also known as runlevels in Linux, play a crucial role in managing the system’s state and functionality. Think of targets as different modes or scenarios your computer can operate in, each with a specific set of services and processes.

In simpler terms, runlevels help define what your computer is supposed to do at different stages – be it during startup, regular operation, or shutdown. For instance, runlevel 3 might focus on a multi-user environment with networking capabilities, while runlevel 5 could include a graphical user interface for a more user-friendly experience.

These runlevels or targets allow users to customize and control the behavior of their Linux system based on their needs. Whether you’re setting up a server that doesn’t require a graphical interface or a desktop environment for everyday use, understanding and configuring runlevels is essential for tailoring your Linux experience.

The content	Command line
List all available targets	systemctl list-unit-files –-type target
Show dependencies of a target	systemctl list-dependencies nginx
Show default boot target	systemctl get-default
Boot to a text console	systemctl set-default multi-user
Boot to a graphical desktop	systemctl set-default graphical

FAQ Section

1. What is the difference between `systemctl` and `journalctl`?

systemctl manages services, units, and targets, while journalctl is used to view logs maintained by Systemd.

2. Can Systemd work alongside other init systems?

Yes, but it’s not recommended as conflicts can arise. Most modern Linux distributions have fully transitioned to Systemd.

3. How do I troubleshoot failed services?

Use:

systemctl status <service-name>

Then, check logs with:

journalctl -u <service-name>

External Resources

Conclusion

You should utilize the helpful Systemd Cheat Sheet in Linux. The cheat sheet includes fundamental systemd commands, and there are even more advanced features and options to explore. For detailed information about specific commands or options, you can check the systemd documentation or man pages (man systemctl). I hope you find this information useful. Thank you for visiting the DevopsRoles page!”

Kubernetes

Kubernetes day one

07/19/2022 HuuPV Leave a comment

Table of Contents

0.1 #Introduction

1 Method installs for Kubernetes.
2 Install Kubectl on Windows
3 Install Minikube on Windows
4 K8S PODS

#Introduction

In this tutorial, We study together K8s (Kubernetes). Let go of Kubernetes day one.

Method installs for Kubernetes.
Use Managed Kubernetes service from CSP.
Install and configure Kubectl for Linux and macOS.
Configuring Kubernetes in Minikube Windows or Linux.
Minikube install commands.
Create the First POD configuration in YAML.
How to generate Pod Manifests via CLI.

Method installs for Kubernetes.

There are multiple methods to get started with a full Kubernetes Environment.

Use the Managed Kubernetes Service.
Install and configure Kubernetes Manually
Use Minikube

Managed Kubernetes Service.

Provides like: AWS, GCP, IBM, and others providers.

Minikube

It’s a tool that makes it easy to run Kubernetes locally.

Minikube run a single node K8s cluster on VM on your laptop. You can try out or develop with it.

Install and configure Kubernetes Manually

It’s the Hard Way. You install and configure components of K8s.

Install Kubectl on Windows

it allows running commands against K8s clusters.

Kubectl to deploy applications, manage cluster resources, and view logs. Link here.

Download Kubectl here

Add path environment variable for K8s

Confirm kubectl command on Windows.

Install Minikube on Windows

Link here.

For example below:

From a terminal start your cluster.

K8S PODS

Kubernetes Pod is a group of one or more application containers that share resources.

A Pod runs on a Node.
Each Node is managed by the Master.
A Node has multiple pods.
A Node is a worker machine in K8s.

The command same docker vs K8s

docker run –name webserver nginx	kubectl run webserver –image=nginx
docker exec -it webserver bash	kubectl exec -it webserver — bash
docker stop webserver docker rm webserver	kubectl delete pod webserver

Updating later!

#Introduction

Deploy Redmine Project Management

Create the Dockerfile

Create the docker-compose.yml file

The deploy the container

Access Redmine

Conclusion

#Introduction

Manage Docker Containers with Yacht

Pull the Yacht docker image

Logging into Yacht

Conclusion

Introduction

Understanding Gitea

Why Choose Gitea?

Prerequisites

Install Gitea repository in Ubuntu

Install the necessary dependencies

Create a database and user

Install Gitea repository

Create a systemd service file for Gitea.

Access the Gitea web-based installer

Conclusion

#Introduction

How to Set A Memory Limit For Docker Containers

Hard memory limits

Soft memory limits

How to setting hard memory limits

How to setting soft memory limits

setting Swap Memory

How to disable Out-Of-Memory process skills.

Conclusion

Introduction

Use find command line

Use the du command line

Linux combines find and du command

Conclusion

Introduction

How to use Bash to create a file

Bash create file: A Guide to Using the Touch Command

shell command

Conclusion

Introduction

How to Password Protect Files on Linux

Encrypt a File with GnuPG

using the zip command to Encrypt a File

Encrypt a File Using mcrypt

Conclusion

Introduction

Ubuntu repository no longer has a Release fixed

Via Youtube

Conclusion

Introduction

Systemd Cheat Sheet in Linux

Logs with systemd

Introspection with systemd

Services

Targets (runlevels)

FAQ Section

1. What is the difference between systemctl and journalctl?

2. Can Systemd work alongside other init systems?

3. How do I troubleshoot failed services?

External Resources

Conclusion

#Introduction

Method installs for Kubernetes.

Managed Kubernetes Service.

Minikube

Install and configure Kubernetes Manually

Install Kubectl on Windows

Install Minikube on Windows

K8S PODS

Devops Tutorial

1. What is the difference between `systemctl` and `journalctl`?