Installation of #27 Linux system: CentOS department

Linux system installation: CentOS Department

Post--bootsequence (BIOS)-BootLoader (Grub-->1.5 Stage-to-2nd stage)-Kernel (DEVTMPFS)-[RA MDisk (Dev,proc,sys)-->] Rootfs--/sbin/init (SysV init,upstart init,systemd)

For the CentOS operating system installed, some of its first-level sub-directories, some can not be separate partitions, some may be separate partitions;

Absolutely no partitioning: bin,sbin,lib,lib64

Create separate partitions: BOOT,HOME,VAR,USR

To install a Linux system:

/boot

Swap

/

/home

/var

/usr

Disk Partitioning planning:

Boot partition

Root partition

Swap

Planning the file system:

/sbin/init,/sbin/systemd

The path where all applications store the path that the application relies on to store the library files

The path that the application relies on for the configuration file to be stored

CentOS System/rhel System installation program: Anaconda

During the installation of the operating system, the system starts the process:

Post--BootLoader-kernel---initrd--rootfs--Anaconda

Anaconda provides us with two operating interfaces:

TUI: Curses-based file configuration window;

GUI: graphical interface;

CLI: Command line interface;

Take the CD as an example, the installation start-up process of the CentOS system:

1.post

2. Read Mbr,boot.cat, which is the bootloader;/isolinux/boot.cat of the CD

3.stage2:/isolinux/isoinux.bin

Configuration file:/isolinux/isolinux.cfg

Label Linux

Tag name, which can be used to refer to the generic name of all the following commands;

Menu label ^install or upgrade an existing system

The specific contents of the menu options and the corresponding hotkey;

Menu default

Use this menu item as the default menu item;

Kernel Vmlinuz

Specify the kernel file name

Append initrd=initrd.img

To pass additional parameters to the kernel, the commonly used parameters are:

Initrd=initrd.img

Text: Starting from a textual interface

Method: Manually select the installation method

Ip=address

Netmask=mask

Gateway=gw

Dns=dns_server

Rescue: Activate emergency rescue mode

DD: Use Kickstart to start an unattended installation, indicating where the kickstart configuration file is located:

On CD: Ks=cdrom:/path/to/kickstart_file

Local hard drive: Ks=h:/device/path/to/kickstart_file

A remote Web site: ks=http://host[:p ort]/path/to/kickstart_file

A remote FTP site: ks=http://[[email protected]]host[:p Ort]/path/to/kickstart_file

A remote security Web site: ks=http://host[:p ort]/path/to/kickstart_file

4. Load the Rootfs and start the Anaconda

Note: If the memory is not 512M, the Anaconda is started with a text interface, and if the memory is greater than 512m,anaconda, it is started by default in graphical interface;

"ECS" key--Boot:linux text

Note: All of the above content is generally located in the boot device, and subsequent Anaconda and other packages or package groups used in the installation can be sourced from the Yum Repository, the location of the Yum Warehouse:

Local Disc

Local hard disk

FTP Server

HTTP Server

Server for NFS

If you want to manually specify a package installation Source:

"ECS" key---Boot:linux method

Anaconda's working process:

Pre-Installation Preparation configuration phase:

1. Language used in the installation process: Simplified Chinese;

2. Keyboard layout type: American English style;

3. Target storage device installed by the system;

Basic storage, local disk;

Special storage, networked storage, Iscsi,nas,san, ... ；

4. Set the host name;

5. Configure the network interface;

6. Select the time zone;

7. Administrator password;

8. Set the partition mode and the location of the MBR installation;

9. Select the package or package group to install;

Installation phase:

1. It is possible to run some pre-installation scripts to complete the initialization work;

2. Partition creation and execution of the format installation file system and mount all file systems to the specified mount point according to the partition format planned in the preparation phase;

3. Install the selected package or package group to the target location;

4. Install the bootloader to the MBR and boot partitions;

5. Making RAMDisk files;

6. If necessary, the post-installation script may be run;

First boot:

1. Select the license information;

2. Create a regular user;

3. Configure Kernel Core dump (Kdump,core dump), if memory is less than 2gb,kdump does not turn on;

When the kernel core crashes at some point, Kdump creates an image file of all the data in memory when the kernel crashes and finds out the direct or indirect cause of the kernel crash by analyzing the contents of the file;

1. Whether to configure iptables firewall; beginners suggest to close;

2. Whether to configure the startup of the SELinux security mechanism, beginners are advised to close;

Kickstart file Format:

Command section: Indicates the configuration of various pre-installation;

Required command:

Authconfig: Configuration of authentication Mode

Authconfig--useshadow--passalgo=sha512

Bootloader: Defining the installation location and related configuration options for bootloader

bootloader--loaction=mbr--driveorder=sda--append= "Crashkernel=auto rhgb quiet"

Keyboard: Setting the type of keyboard

Keyboard US

Lang: Language type during installation

Lang Zh_cn. UTF-8

Part: partition layout and how partitions are used

Part/boot--FSTYPE=EXT4--size=200

Part swap--size=2048

Part Pv_name--size=51200--grow

Clearpart: Clear Partition

Clearpart--none--DRIVES=SDA

Volgroup: Command to create a volume group

Vo the group vg_name--pesize= 8192 pv_name

Logvol: The command to wear a logical volume

Logvol/home--FSTYPE=EXT4--name=lv_home--vgname=vg_name--size=10240

Logvol/var--FSTYPE=EXT4--name=lv_home--vgname=vg_name--size=10240

LOGVOL/USR--FSTYPE=EXT4--name=lv_home--vgname=vg_name--size=10240

ROOTPW: Indicates the root password of Superuser

ROOTPW--iscrypted $6$salt$encrypted_pass

TimeZone: Time zone

TimeZone Asia/shanghai

The command can be selected:

Install: New operating system installed

Upgrade: Upgrading and installing the operating system

Text: Install the operating system using the interface, default is GUI;

Network: Configuring the Networking Interface

Network--onboot Yes--device eth0--bootproto static--ip 172.16.72.1--netmask 255.255.0.0--noipv6--hostname a.link.co M

Firewall: Firewall settings

Firewall:--disabled

Firewall:--service=ssh

Settings for Selinux:selinux

SELinux--disabled

SELinux--enforcing

Off Topic:

If you plan to have the firewall and SELinux enforcement mode turned on, you can turn it off in dozens of ways:

Firewall

CentOS 6:

# Service Iptables Stop

#chkconfig iptables off

CentOS 7:

# Systemctl Stop Firewalld.service

# systemctl Disable Firewalld.service

If you want the firewall to temporarily not take effect;

# iptables-f applies to all CentOS system versions;

SELinux

1. Edit the SELinux configuration file/etc/sysconfig/selinux (/etc/selinux/config), in the configuration file, a line of statements is: selinux={disabled|enforce|permissive }

2. Edit the Grub startup profile/boot/grub/grub.conf

Kernel/vmlinuz-version-release ARGS selinux=0

If you want SELinux to temporarily not restrict user behavior:

# Setenforce 0 = = enforcing-permissive

# setenforce 1 = = permissive-Enforcing

# Getenforce

Repo: Install the system with the use of the repository

Repo--name= "CentOS"--baseurl=cdrom:sr0--cost=100

Repo--name= "CentOS"--baseurl=http://host[:p ort]/path--cost=100

Reboot: Restart after installation is complete

Halt/poweroff: Shut down the system after installation is complete

URL: Indicates the repository used at installation, but must use URL format;

URL--url=http://host[:p Ort]/path

Firstboot--disable: First boot off

Script segment:

%per: The beginning of the pre-installation script

Operating environment: The Linux system environment running on the installation ring;

%end

%post: The beginning of the post-installation script

Running Environment: Install the operating system after

%end

Package/Package Group segment: Indicates the package or package group to install and does not install the package;

%packages

@pack_group_name: Install a package group;

Pack_name: Installs a single specified package;

-pack_name: Explicitly indicate a package that is not installed; Sometimes the specified package may be installed (installed in other packages or dependent on other programs), even if it is explicitly indicated;

%end

How to create a Kickstart file:

1. Directly to the Anaconda-ks.cfg template, after the copy can be modified;

2. Tools can be used to create;

If the command does not exist, the Yum install System-config-kickstart installs;

# System-config-kickstart &

Can be created entirely new, can also be based on other KS files (such as anaconda-ks.cfg) to modify the generation of new configuration files;

3. Check the KS file syntax for errors:

Ksvalidator

If the command does not exist, you can install the Pykickstart-1.74.20-1.el6.noarch

Http://172.16.72.1/ks.cfg

Build a Web server with a CentOS7 by using one of the following methods:

Temporarily clean up the firewall rules and set SELinux to permissive mode:

~]# iptables-f

~]# Setenforce 0

Start the Web service

~]# systemctl Start Httpd.service

View the running status of the Web service, as long as there is a green text display of active (running), which is the normal start of the service;

~]# systemctl Status Httpd.service

Provides repository for CentOS 6

~]# Mkdir/var/www/html/centos_6_repo

~]# Mount/dev/sr0/mnt/cdrom

Note: The CD-ROM is placed in the CentOS6 installation CD CD1;

~]# cp-a/mnt/cdrom/*/var/www/html/centos_6_repo

To this, the configuration of the Web server is complete;

Create a bootable CD using one of the installed CentOS 6 operating systems:

Write the following to the kickstart file;

~]# vim/root/centos6-ks.cfg

#platform =x86, AMD64, or Intel EM64T

#version =devel

# Firewall Configuration

Firewall--disabled

# SELinux Configuration

SELinux--disabled

# Install OS instead of upgrade

Install

# Use Network Installation

Network--onboot Yes--device eth0--bootproto DHCP

URL--url= "Http://172.16.72.1/myrepo"

# Root Password

ROOTPW--iscrypted $1$irhppr42$vmesh73wbqhutjkp6oyod.

# System Authorization Information

Auth--useshadow--passalgo=sha512

# Use text mode install

Text

Firstboot--disable

# System Keyboard

Keyboard US

# System Language

Lang en_US

# SELinux Configuration

SELinux--disabled

# Reboot after installation

Reboot

# System TimeZone

TimeZone Asia/shanghai

# System Bootloader Configuration

Bootloader--append= "RHGB crashkernel=auto quiet"--location=mbr--driveorder= "SDA"

# Clear the Master Boot Record

Zerombr

# Partition Clearing Information

Clearpart--all

# Disk Partitioning Information

Part/boot--fstype= "Ext4"--size=200

Part pv.008--size=61440

Volgroup MYVG--pesize=4096 pv.008

Logvol/--FSTYPE=EXT4--name=root--VGNAME=MYVG--size=20480

Logvol Swap--name=swap--VGNAME=MYVG--size=2048

LOGVOL/USR--FSTYPE=EXT4--name=usr--VGNAME=MYVG--size=10240

Logvol/var--FSTYPE=EXT4--name=var--VGNAME=MYVG--size=20480

#repo--name= "CentOS"--baseurl=cdrom:sr0--cost=100

%post

Echo-e ' Qhdlink Linux for Learning services\nhttp://www.linklinux.com\n ' >>/etc/issue

Sed-i ' 1,[email protected]:[0-9]:initdefault: @id: 3:initdefault:@g '/etc/inittab

Ifconfig eth0 172.16.69.2/16

%end

%packages

@base

@core

@debugging

@basic-desktop

@desktop-debugging

@desktop-platform

@desktop-platform-devel

@development

@directory-client

@fonts

@general-desktop

@graphical-admin-tools

@input-methods

@internet-applications

@internet-browser

@java-platform

@legacy-X

@network-file-system-client

@office-suite

@print-client

@remote-desktop-clients

@server-platform

@server-platform-devel

@server-policy

@workstation-policy

@x11

Mtools

Pax

Python-dmidecode

Oddjob

Wodim

Sgpio

Genisoimage

Device-mapper-persistent-data

Systemtap-client

Abrt-gui

Desktop-file-utils

Jpackage-utils

Samba-winbind

Certmonger

Pam_krb5

Krb5-workstation

Openmotif

Libxmu

Libxp

%end

To create a bootable disc:

~]# mkdir Myiso

~]# Cp-r/mnt/cdrom/isolinux/root/myiso/

Note: This method of replication is to copy the Isolinux directory directly into the Myiso directory, that is, Isolinux is a subdirectory of Myiso;

~]# vim/root/myiso/isolinux/isolinux.cfg

Label Linux

Menu label ^install or upgrade an existing system

Menu default

Kernel Vmlinuz

Append initrd=initrd.img ks=cdrom:/centos6-ks.cfg

~]# cp/root/centos6-ks.cfg/root/myiso/

~]# mkisofs-r-j-t-v--no-emul-boot--boot-load-size 4--boot-info-table-v "CentOS 6 x86_64 Boot"-B isolinux/isolinux . bin-c Isolinux/boot.cat-o/root/boot.iso myiso/

Create a USB drive boot disk

Method One:

~]# DD If=/dev/sr0 OF=/DEV/SDB

Method Two:

~]# Fdisk/dev/sdb (divides the entire USB drive into one partition and modifies its partition type to VFAT, that is, use the T-to-B command to complete the conversion in Fdisk interactive mode)

~]# MKFS.VFAT/DEV/SDB1

~]# Mount/dev/sdb1/mnt/usb

~]# mkidr-p/mnt/usb/grub

~]# cp/mnt/cdrom/isolinux/{vmlinuz,initrd.img}/MNT/USB

~]# vim/mnt/usb/grub/grub.conf

Default=0

Timeout=5

Title The Linux boot from USB

Root (hd0,0)

Kernel/vmlinuz

Initrd/initrd.img ks=http://172.16.72.1/ks.cfg (Place the Centos6-ks.cfg file in the/var/www/html directory of CentOS7 and change the name to Ks.cfg)

~]# Grub

grub> Root (hd1,0)

grub> Setup (HD1)

Installation of #27 Linux system: CentOS department