Red Hat Certified System Administrator (RHCSA) EX200 Study Guide

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12/ 17/ 12 www. linuxexplor er s. com / r ed- hat - cer t if ied- syst em - adm inist r at or - r hcsa- ex200- st udy- guide/ 4/ 11 and tail Access a virtual machine’s console. # v irt-v iewer REDHAT VM Start and stop virtual machines. # v irsh start REDHAT VM # v irsh shutdown REDHAT VM (Attempts a “graceful sy stem shutdown) # v irsh destroy REDHAT VM (Equivalent to turning off the sy stem with the power button unsaved data may be lost with this option. Start, stop, and check the status of network services. # serv ice start //example: service httpd start # serv ice stop # serv ice restart # serv ice status # checkconfig on //turns on service at boot # checkconfig off //turns off services at boot Configure local storage List, create, delete, and set partition type for primary, extended, and logical partitions. List partitions: # fdisk -l Delete: partitions 1) Open the drive with: # fdisk /dev /sda 2) Press “c” to turn off DOS-compatible mode and the “u” to display units in sectors. 3) Ty pe n for a new partition. Each disk can have 4 primary partitions which are number 1-4. Partition 5 is the extended partition and partitions 6 – X are logical partitions. 4) Press “w” to write the changes to the disk or “q” to exit without saving changes. Create and remove physical volumes, assign physical volumes to volume groups, and create and delete logical volumes. Create phy sical volume: # pv create -v /dev /sda1 /dev /sda2 Create volume group: # v gcreate -v -s 32 VG01 /dev /sda1 /dev /sda2 Create logical volume: # lv create -v 10g -n LV01 VG01
12/ 17/ 12 www. linuxexplor er s. com / r ed- hat - cer t if ied- syst em - adm inist r at or - r hcsa- ex200- st udy- guide/ 5/ 11 # lv create -v 15g -n LV02 VG01 Explanation: In order to create a logical volume the first thing that needs to be done is to format the partitions so they can be added to a volume group. This is done with the “pvcreate” command. The next step is to add the phy sical volumes to the volume group and that is done with the vgcreate command. The “-s 32” option define the phy sical extent size. The phy sical extent size determines the maximum size of the logical volume and the default phy sical extent size which 4mb. There are 65,536 phy sical extents available to a volume group with gives y ou a total size of 262,114mb or 256gb (4mb x 65,536 mb = 262,114mb) for the volume group. By setting the extent size to 32mb the maximum size of the volume group would be 2,097 ,152mb or approximately 2 teraby tes (32mb x 65,536 = 2,097 ,152mb). Once the volume group has been defined the next step is to add the logical volumes to the volume group. The volumes created in the example above will be located in /dev/VG01/LV01 and /dev/VG01/LV02 these logical volumes can now be formatted with a file sy stem, mounted and placed in the fstab so that they are mounted when the sy stem boots. Format the Volumes # m kfs.ext4 /dev /VG01/LV01 # m kfs.ext4 /dev /VG01/LV02 Delete Volumes In order to remove the volumes y ou will need to run the following sequence of commands. # lv rem ov e /dev /VG01/LV01 # lv rem ov e /dev /VG01/LV02 # v grem ov e /dev /VG01 # pv rem ov e /dev /sda1 /dev /sda2 Create and configure LUKS-encrypted partitions and logical volumes to prompt for password and mount a decrypted file system at boot. The following procedure assumes that the dm_cry pt module has been loaded. For a more detailed explanation please see # cry ptsetup luksForm at /dev /sda1 //formats the drive and prompts y ou to create a passphrase # cry ptsetup luksOpen /dev /sda1 luks01 //opens drive /dev/sda1 and maps it to /dev/mapper/luks01 # m kfs.ext4 /dev /m apper/luks01 //formats the volume with the ext4 file sy stem. Now that the LUKS-encry pted volume has been created and formatted it can be added to the boot process. Create an “/etc/cry pttab” file. Add the following line to the file and save it: luks01 /dev /sda1 the cry pttab file will attempt to open the encry pted volume at boot and will prompt y ou for a password. If the file is successfully opened its mapped to /dev/mapper/luks01
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Red Hat Certified System Administrator (RHCSA) EX200 Study Guide

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