RHCSA RHEL 8 - Interrupt the boot process in order to gain access to a system скачать в хорошем качестве

RHCSA RHEL 8 - Interrupt the boot process in order to gain access to a system

Buy CSG Merchandise: http://tee.pub/lic/csg Patreon page:   / computers_servers   This video is based on RHEL 8. Video to cover the section 'Interrupt the boot process in order to gain access to a system' for the RHCSA (Red Hat Certified System Administrator). More information on the required learning: http://bit.ly/rhcsa8 Notes from the video: Resetting the Root Password Using an Installation Disk Start the system and when BIOS information is displayed, select the option for a boot menu and select to boot from the installation disk. Choose Troubleshooting. Choose Rescue a Red Hat Enterprise Linux System. Choose Continue which is the default option. At this point you will be promoted for a passphrase if an encrypted file system is found. Press OK to acknowledge the information displayed until the shell prompt appears. Change the file system root as follows: chroot /mnt/sysimage Enter the passwd command and follow the instructions displayed on the command line to change the root password. passwd Remove the autorelable file to prevent a time consuming SELinux relabel of the disk: rm -f /.autorelabel Enter the exit command to exit the chroot environment. Enter the exit command again to resume the initialization and finish the system boot. Resetting the Root Password Using rd.break Start the system and, on the GRUB 2 boot screen, press the e key for edit. Remove the rhgb and quiet parameters from the end, or near the end, of the linux16 line, or linuxefi on UEFI systems. Add the following parameters at the end of the linux line on 64-Bit IBM Power Series, the linux16 line on x86-64 BIOS-based systems, or the linuxefi line on UEFI systems: rd.break enforcing=0 Adding the enforcing=0 option enables omitting the time consuming SELinux relabeling process. The initramfs will stop before passing control to the Linux kernel, enabling you to work with the root file system. Note that the initramfs prompt will appear on the last console specified on the Linux line. Press Ctrl+x to boot the system with the changed parameters. With an encrypted file system, a password is required at this point. However the password prompt might not appear as it is obscured by logging messages. You can press the Backspace key to see the prompt. Release the key and enter the password for the encrypted file system, while ignoring the logging messages. The initramfs switch_root prompt appears. The file system is mounted read-only on /sysroot/. You will not be allowed to change the password if the file system is not writeable. Remount the file system as writeable: mount -o remount,rw /sysroot The file system is remounted with write enabled. Change the file system's root as follows: chroot /sysroot The prompt changes to sh-4.2#. Enter the passwd command and follow the instructions displayed on the command line to change the root password. passwd Updating the password file results in a file with the incorrect SELinux security context. To relabel all files on next system boot, enter the following command: touch /.autorelabel Alternatively, to save the time it takes to relabel a large disk, you can omit this step provided you included the enforcing=0 option in step 3. Remount the file system as read only: mount -o remount,ro / Enter the exit command to exit the chroot environment. Enter the exit command again to resume the initialization and finish the system boot. With an encrypted file system, a pass word or phrase is required at this point. However the password prompt might not appear as it is obscured by logging messages. You can press and hold the Backspace key to see the prompt. Release the key and enter the password for the encrypted file system, while ignoring the logging messages. Note that the SELinux relabeling process can take a long time. A system reboot will occur automatically when the process is complete. If you added the enforcing=0 option in step 3 and omitted the touch /.autorelabel command in step 8, enter the following command to restore the /etc/shadow file's SELinux security context: restorecon /etc/shadow Enter the following commands to turn SELinux policy enforcement back on and verify that it is on: setenforce 1 getenforce Enforcing #rhcsa #rhel #linux