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I believe you have seen in many places "Docker based on Mamespace, Cgroups, chroot and other technologies to build containers," but have you ever wondered why the construction of containers requires these technologies? 　　Why not a simple system call? The reason is that the Linux kernel does not have the concept of "Linux container", the container is a user state concept. Docker software engineer Michael Crosby will write some blog posts and dive into Docke ...

Basically all system calls return 0 or positive numbers when they succeed, and negative values are returned when they fail. Process User ID management system call format #include <unistd.h> unsigned short getuid () unsigned short getgid () unsigned short geteuid () unsigned short getegid () int setuid (int uid) int s ...

Editor's note: The last period of time reproduced in the "5 minutes to understand docker! "Very popular, a short 1500 words, let everyone quickly understand the Docker." Today, I saw the author make a new novel, and immediately turned over. The reason to call this code reading as a fantasy trip is because the author Liu Mengxin (@oilbeater) in the process of reading Docker source, found a few interesting things: from the code point of view Docker did not start a new development mechanism, but the existing tested isolation security mechanism to use the full use, Including Cgroups,c ...

RABBIT-MQTT+PMQTT Protocol +paho Library (ubuntu16.04). Step 1 Download Install RABIIT-MQ mqtt-server on the Deb package another need sudo apt install erlang 2 boot sudo/etc/init.d/rabbitmq-server restart 3 mqtt-3.1 protocol support Rabbitmq-plugins Enable ...

In the computer hardware contains a system clock, the system is guided to read the clock, and then maintain its own clock counter, using the clock counter to the system events, such as the creation of files or user login to give time records. The clock value can also be used by the time () system call for your own program: #include <sys/types/h> #include (time.h> time_t time (time_t *loc); This system call returns a time ...

The rapid development of network technology, so that enterprises and institutions local area network access to the Internet to share resources more and more, for the most part, DDN dedicated line with its stable performance, the advantages of good expansion into a common way, DDN way of connection in the hardware requirements is simple, Only one router (router) and proxy server (proxy server) is required, but the configuration of the system is a tricky issue for many network administrators. Take the Cisco router as an example: first, directly through the router to access inter ...

In large data technology, Apache Hadoop and MapReduce are the most user-focused. But it's not easy to manage a Hadoop Distributed file system, or to write MapReduce tasks in Java. 　　 　　Then Apache hive may help you solve the problem. The Hive Data Warehouse tool is also a project of the Apache Foundation, one of the key components of the Hadoop ecosystem, which provides contextual query statements, i.e. hive queries ...

Script on /home/user/mysql_backup.sh crontab # crontab -l # m dom dom dow downgrade 28 16 * * * / home / user / m ...

"Guide" the author (Xu Peng) to see Spark source of time is not long, note the original intention is just to not forget later. In the process of reading the source code is a very simple mode of thinking, is to strive to find a major thread through the overall situation. In my opinion, the clue in Spark is that if the data is processed in a distributed computing environment, it is efficient and reliable. After a certain understanding of the internal implementation of spark, of course, I hope to apply it to practical engineering practice, this time will face many new challenges, such as the selection of which as a data warehouse, HB ...

php tutorial + mysql tutorial database tutorial unlimited classification code This paragraph php infinite classification code more complete, including the database is mysql, add, delete, edit, move the function, while also providing the database sql table structure // connect to the database $ link = mysql_connect ('localhost', 'root', '') or die (mysql_error ()); mysql_select_db ('class', $ link) or d ...