Cloud Applications

Vim/etc/sysctl. conf1, net. ipv4.tcp _ max_syn_backlog = 65536 records the maximum number of connection requests that have not received confirmation from the client. For systems with over 1024 MB of memory, the default value is 128. for systems with

There are still a lot of commands to check the gateway in Linux. However, if the IP address is obtained through DHCP, some commands are not applicable. of course, there are also common query gateway commands. 1.cat/ etc/resolv. conf (see DNS) 2.

If our servers are not deployed locally (usually hosted in the IDC), and there are more than one server in the IDC, when one of them is disabled, then we can remotely connect to a server that has not been shut down and start the instance remotely.

The Linux server allocates real and virtual memory to the processor and manages memory usage through swap. Understanding the Linux memory type and how the processor shares memory helps optimize memory usage. Memory is allocated from the Linux kernel

The commands listed in this article cannot be run, even if you are curious, unless you are running on a virtual machine (you can restore the problem ), because they will actually damage your system. Therefore, it is a good habit not to execute

As we all know, the current time-sharing operating system can run multiple programs on a single CPU, making these programs seem to be running at the same time. Linux is such an operating system. In linux, each running program instance corresponds to

By default, the Linux system uses the/etc/inittab file to control whether reboot or shutdown is performed when the system simultaneously presses the -- combination key before the system terminal. If you want to, you can completely disable this

Recently, several servers were found to have zombie processes (). Run the following command to find out the zombie process ps-A-ostat, ppid, pid, cmd | grep-e '^ [Zz]' command annotation: -parameter A lists all process-o custom output fields. we set

Use the test command for files, strings, and numbers. Use the expr command for numbers and strings. Expr command to test and execute numerical output. Run the exit command $? Test and expr can be tested, both of which indicate 0 is correct, and 1

# Group account management linux group management =-= -= 1. classification private group: only one user can be included (automatically created by the created user) Standard Group: can contain multiple users 2. information group name of the group:

1. add the port vim/etc/ssh/sshd_config and remove the comment of # Port22 and add the line feed to Port57788. if the comment is added but the comment is modified, we recommend that you keep port 22 first, and then remove the new port. We recommend

1. the disk partition format indicates that linux partitions are different from windows. in linux, the hard disk device name (hdx for IDE hard disks (x for disks from a-d) is used because up to four hard disks of IDE, SCSI, SATA, the USB hard disk

The telnet and ssh services can only implement remote control based on the character interface. if you want to implement remote control based on the graphical interface, you can use free VNC. 1. telnet connection 1. first enter the terminal to check

A linux System Kernel upgrade record, with some and IPVS kernel module, linux boot sequence and other related knowledge, for future reference to the upgrade before the OS information # lsb_release-aLSBVersion: core-3.1-amd64: core-3.1-ia32: core-3.1-

1. locate --- & gt; search for the database generated in advance, fuzzy search, updatedb update the locate database-I: ignore the case of the file name-n: only show the first n rows of eg: lo 1. locate ---> searches for the database generated in

Two Linux machines log on to each other using ssh without A password. assume that user user1. On HostA, run ssh-keygen to generate the private key id_rsa and public key id_rsa.pub as user1, and then run the command ssh-copy-iduser1 @ HostB to copy

Yum is a background program used to manage rpm packages. it is written in python and can easily solve rpm dependencies. After the yum server is created, the yum client can obtain the software package through http and ftp, and directly manage and

It is useful in redhat and centeros: mainly to change the i18n file:/etc/sysconfig/i18n note i18n the second character is the number of characters = "zh_CN.GB2312" SUPPORTED = "zh_CN.GB2312: zh_CN: en "SYSFONT =" latarcyrheb-sun16 "-------------

The deep sleep of centos may occur because the screen is closed and there is no operation for a long time. in this case, you can only force the restart by using the power key. You can modify the X11 configuration to disable sleep. the configuration

Start vim open multiple files and split screen display: vim-onfile1file2o is lowercase letters, upper and lower points, n is the number of split screen, followed by the file to be opened vim-Onfile1file2O is uppercase letters, left and right points,