Detailed explanation of useradd command

The key differences between CentOS and Ubuntu are: origin (CentOS originates from Red Hat, for enterprises; Ubuntu originates from Debian, for individuals), package management (CentOS uses yum, focusing on stability; Ubuntu uses apt, for high update frequency), support cycle (CentOS provides 10 years of support, Ubuntu provides 5 years of LTS support), community support (CentOS focuses on stability, Ubuntu provides a wide range of tutorials and documents), uses (CentOS is biased towards servers, Ubuntu is suitable for servers and desktops), other differences include installation simplicity (CentOS is thin)

Docker uses Linux kernel features to provide an efficient and isolated application running environment. Its working principle is as follows: 1. The mirror is used as a read-only template, which contains everything you need to run the application; 2. The Union File System (UnionFS) stacks multiple file systems, only storing the differences, saving space and speeding up; 3. The daemon manages the mirrors and containers, and the client uses them for interaction; 4. Namespaces and cgroups implement container isolation and resource limitations; 5. Multiple network modes support container interconnection. Only by understanding these core concepts can you better utilize Docker.

CentOS will be shut down in 2024 because its upstream distribution, RHEL 8, has been shut down. This shutdown will affect the CentOS 8 system, preventing it from continuing to receive updates. Users should plan for migration, and recommended options include CentOS Stream, AlmaLinux, and Rocky Linux to keep the system safe and stable.

How to use Docker Desktop? Docker Desktop is a tool for running Docker containers on local machines. The steps to use include: 1. Install Docker Desktop; 2. Start Docker Desktop; 3. Create Docker image (using Dockerfile); 4. Build Docker image (using docker build); 5. Run Docker container (using docker run).

CentOS installation steps: Download the ISO image and burn bootable media; boot and select the installation source; select the language and keyboard layout; configure the network; partition the hard disk; set the system clock; create the root user; select the software package; start the installation; restart and boot from the hard disk after the installation is completed.

Backup and Recovery Policy of GitLab under CentOS System In order to ensure data security and recoverability, GitLab on CentOS provides a variety of backup methods. This article will introduce several common backup methods, configuration parameters and recovery processes in detail to help you establish a complete GitLab backup and recovery strategy. 1. Manual backup Use the gitlab-rakegitlab:backup:create command to execute manual backup. This command backs up key information such as GitLab repository, database, users, user groups, keys, and permissions. The default backup file is stored in the /var/opt/gitlab/backups directory. You can modify /etc/gitlab

CentOS hard disk mount is divided into the following steps: determine the hard disk device name (/dev/sdX); create a mount point (it is recommended to use /mnt/newdisk); execute the mount command (mount /dev/sdX1 /mnt/newdisk); edit the /etc/fstab file to add a permanent mount configuration; use the umount command to uninstall the device to ensure that no process uses the device.

After CentOS is stopped, users can take the following measures to deal with it: Select a compatible distribution: such as AlmaLinux, Rocky Linux, and CentOS Stream. Migrate to commercial distributions: such as Red Hat Enterprise Linux, Oracle Linux. Upgrade to CentOS 9 Stream: Rolling distribution, providing the latest technology. Select other Linux distributions: such as Ubuntu, Debian. Evaluate other options such as containers, virtual machines, or cloud platforms.