Programmer Group

Reason Recently, I purchased a new server to get something new. First, I want to achieve password-free login (i.e. user password login). Then, I don't want to use root login, so I searched a lot of data on the Internet, and now summarize some for myself to fumble around in the future._ These are for yourself, don't look for me if you can't un ...

Common hadoop cluster namenode(nn) secondarynamenode(2nn) datanode(dn) The problems of common hadoop cluster Is there a single point of failure with datanode? No, because datanode has multiple machines and a copy mechanism as guarantee Is there a single point of failure with the namenode? Yes, because 2nn can't replac ...

Log in to the direct connection interface (DCUI) of ESXi 6.7 host, and we will see the following function option: Restart Management Agents. Even the description on the right is vague. What services are these so-called Management Agents? Why not translate this Agent into "Agent", but into "service"? The word agent is ver ...

In the CenOS 7 system, openssh server is provided by openssh, openssh server and other software packages (installed by default), and sshd has been added as a standard system service. You can execute systemctl status sshd to view the status of the service. As long as you have a legal login shell, you can log in to the operating system remotely ...

The previous article wrote about how to build a reusable image of tomcat. This article talked about how to use this image to build different projects repeatedly. Go straight to the subject: Step 1 create the corresponding mavn project job Other configurations remain the same. The main change is the action after the build project. Note: becaus ...

Part II: configuration of ROS network communication brief introduction Local area network configuration Using dandelion VPN to realize remote networking brief introduction This article includes two aspects: On the one hand, it is the simplest LAN, which can be completed without too much configur ...

Getting started with Git What is Git? Create version library information and configure user information Submit modification process View operation Revocation Version rollback Branching operation Storage work area Remote warehouse What is Git? Git is the most advanced distributed version control ...

If you normally operate the database on the command line, it is highly recommended that you use the following command-line tools. mycli Mycli is a MySQL based command-line tool, which is directly installed by pip install mycli. For details, see https://github.com/dbcli/mycli $ mycli --help Usage: mycli [OPTIONS] [DATABASE] A MySQL terminal c ...

I. experimental requirements 1. The backup machine needs to synchronize all files under the / app/java_project directory of the MIS server at 1:03 a.m. every day. 2. It is required to record the synchronization log to facilitate the analysis of synchronization failure. II. Task analysis 1. Use crontab to write scheduled tasks 2. Use rsync for r ...

Catalog 1. Modify function function or class property 2. Modify environment variables 3. Modify dictionary Sometimes, the test case needs to call some functions that depend on the global configuration, or these functions themselves call some code that is not easy to test (for example, network access ...