Linux Rookie starter 2 system Recovery and SELinux

Primary management of SELinux  

1. What is a SELinux

Selinux : kernel-level enhanced firewall

2. How to manage SELinux levels

SELinux turned on or off  

Vim/etc/sysconfig/selinux

selinux=disabled off state

selinux=enforcing Mandatory State

selinux=permissive Warning status

Getenforce View status

when SELinux is turned on

Setenforce 0|1 changing the SELinux run level

3. How to change the file security context

Temporary changes

chcon-t Security Context File

Chcon-t Public_content_t/publicftp-r

Permanent changes

semanage fcontext-l # #列出内核安全上下文列表内容

Semanage fcontext-a-T public_content_t '/publicftp (/.*)? '

restorecon-fvvr/publicftp/

4. How to control the SELinux switch to the service function

getsebool-a | grep service Name

getsebool-a | grep FTP

setsebool-p function bool value On|off

setsebool-p Ftpd_anon_write on

5. Monitor the SELinux error message

Setroubleshoot-server

System Recovery

1. System Startup process

Power

BIOS (in read-only storage on the motherboard, basic input or output system)

function, hardware detection, activation hardware

Grub System boot (grub boot divided into two stages)

1) Stage 1 MBR (Master boot record) master boot record 0 tracks on hard disk, one sector, 446 bytes

*) dd If=/dev/zero Of=/dev/vda bs=446 count=1 can empty MBR

*) go to save mode, perform chroot/mnt/sysimage switch to real/environment,

and execute GRUB2-INSTALL/DEV/VDA

2) Phase 2 Grub File boot phase

Locate the/boot partition

Read /boot/grub2/grub.cfg

file lost,grub2-mkconfig >/boot/grub2/grub.cfg

boot kernel, read-only mount /device

Testing equipment

Initialize the device driver

Enter the system initialization phase

Kernel is missing, the new kernel installation package can be resolved

RPM-IVH kernel-xxxxx.rpm--force

System initialization phase

system initialization phase load INITRD mirror

Open Initialization Process SYSTEMD

Start SELinux

Load Kernel parameters

Initialize the system clock, keyboard, host name

re-read/write mount /device

activating RAID,LVM

Activate quotas

start All services in the multi-user.target.wants

Turn on the Virtual Console

Start graphics

initramfs-' Uname-r '. IMG Lost by:

MKINITRD initramfs-' uname-r '. img ' uname-r '

Recovery

Enter rescue mode, PXE boot or CD-ROM (hang ISO image), troubleshoot, rescue mode Chroot/sysimage

Change Password

Start the system--"up and down" key interrupt read seconds-"E into the editor-" to modify the system initialization statements into read-write mode, Rd.break.

--"Change password--" Generate Automklebal file to let the system load the modified password

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Linux Rookie starter 2 system Recovery and SELinux