Chapter One: server hardware and linux first experience
First, understand the linux;
1.linux of three branches: debian, redhat, ubuntu
2.redhat version:
redhat: Red Hat, referred to as RHEL, enterprise-level official version, the free version;
centos: business community operating system version, does not belong to Red Hat, but be based on source community version of Red Hat's reconstruction, code components;
3. Install linux system Precautions:
. A CD-ROM into the ISO file, click on the link;
. B Select Now custom installation package, check the development of tools when using the default disk partition, the installation system;
4. The specific parameters:
Zoning: Zoning can be understood as a house of partition;
File system: A method for the external storage device management and organization of files, it can be understood as a house renovation program;
Format: can be understood as the beginning of the decoration of a house, clear out all previous configuration;
5. Upon completion of the installation system optimization:
关闭selinux：sed -i "/SELINUX/s/enforcing/disabled/g" /etc/selinux/config
Boot does not start the firewall: chkconfig iptables off
Verify selinux is closed: getenforce
File system type 6.centos 6 version of the system:
EXT4: fourth generation extended file system, the main area for storing data files and directories;
SWAP: swap file system, a swap partition for linux system, can alleviate the shortage of physical memory;
Attachment:
Centos virtual machine installation steps:
1. Download the image files and virtual machine software;
2. Create a virtual machine in vmware;
3. Connect centos6.5DVD1 image file;
4. The mounting system (desktop environment can be selected or minimum installation, note that the check tools);
5. Close the firewall;
/etc/init.d/iptables stop ## temporarily shut down the firewall state
chkconfig iptables off ## Power disable the firewall
6. Close selinux:
Find the system / etc / selinux / config file selinux = enforcing into selinux = disabled;
7. easy to take snapshots off the next use;
Two, init process;
1.linux system boot:
Boot bios POST --MBR guide --GRUB guide - load the kernel - Load init process - start tty-- landing system
2.init process:
Process: linux process in the system with PID tag, / sbin / init is first loaded kernel process, PID is 1;
Run level field: runlevel
0-- single-user shutdown 1-- 2-- 3-- no network character complete character 4-- 5-- not use graphics mode 6-- restart
init run levels: this command indicates switching to a different operating state levels
Third, the system services control:
1. control of a state of the service:
Syntax: service name of the service control type
Control Type: start ## to start the service
stop ## stop this service
restart ## Restart the service
reload ## reload this service
view the status of the service status ##
2. The control of the service status of two:
Syntax: /etc/init.d/ service name type of control
Control Type: ditto the same type of control
3. control the startup type of services (whether to activate the boot):
Syntax: chkconfig service name type of control
Control Type: on ## boot automatically start this service
off ## boot does not start this service
Syntax: chkconfig --list service name ## view this type of state service starts running at different levels of
语法：chkconfig --add 服务名称 ##添加此服务到ckhconfig的管理列表中
四、扩展：
uname -r ##查看内核版本信息
uname -a ##查看系统版本信息
free -m ##查看系统内存状态信息
df -hT ##查看系统磁盘信息
hostname ##查看主机名
五、Centos 7 扩展：
1.systemctl进程：代替在Centos 6中的init进程，因为init进程启动时是串行化的，速度较慢，Centos 7在这一点做了优化；
2.运行级别：
systemctl get-default ##查看当前的默认运行级别
systemctl set-default 运行级别标签 ##设置系统的默认运行级别
init 运行级别数字 ##切换当前的运行级别