Scenario: Reset root password CentOS/RHEL 7
System: CentOS/RHEl 7
Steps:
1) On first boot menu select first kernel(on top) then Press ‘e’
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Reset Root Password CentOS 7
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Create LUN in Openfiler
Scenario: Create LUN in Openfiler from new disk.
System: Openfiler ESA 2.9
Steps:
1) Click Volumes >> Click Block Devices,in picture below we see new drive /dev/sdb and /dev/sdc as plan we will create LUN in /dev/sdb then continue click /dev/sdb.
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Install Openfiler
Scenario: Installing Openfiler at sda 40GB size.
System: Openfiler ESA 2.99.1
Steps:
– Download Openfiler iso from here.
– Booting from Openfiler iso/DVD.
– Select Graphical Mode press Enter.
– Click Next.
– Select Keyboard -> Click Next then select Yes to initialize drive,erasing ALL DATA.
– Continue click Next if using default Openfiler partition table. I setup LVM for /var and swap for easy increase the space in the future.
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Extend Volume Group and Logical Volume on CentOS 7
Scenario: Added new disk /dev/sdc then extend Volume Group and extend Logical Volume /var on CentOS 7
System: CentOS 7
Steps:
– After added disk /dev/sdc then create partition on /dev/sdc
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Create Partition on New Disk using Parted on CentOS
Scenario: Create partition and Volume Group 60GB size from 100GB disk on new disk using Parted on CentOS
System: CentOS/RHEL 6 or 7
Steps:
Show new disk:
# fdisk -l | grep sd
[root@server ~]# fdisk -l | grep sd
Disk /dev/sda: 64.4 GB, 64424509440 bytes, 125829120 sectors
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 81797119 39848960 8e Linux LVM
Disk /dev/sdb: 107.4 GB, 107374182400 bytes, 209715200 sectors
[root@server ~]#
Mount Windows Folder Sharing on RHEL 6/CentOS 6
Scenario:
-Mount Windows Folder Sharing (CIFS) on RHEL 6/CentOS 6.
-Set only Linux user >> user1 that have RWX access.
-Hide sharing credentials from other Linux users.
-Mount permanent at boot.
System: CentOS 6
Steps:
1) Edit /etc/fstab
# vi /etc/fstab
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Setup Virtual Domain Postfix
Scenario:
– Forward certain email recipient to another email address.
– Forward local Unix account email address to another email recipient because in the Postfix server don’t have mailbox.
System:
Postfix on CentOS 7/RHEL 7 (also work on CentOS 6/RHEL 6)
Steps:
– Edit main.cf
# vi /etc/postfix/main.cf
Edit the below parameter.
virtual_alias_domains = example1.com,example2.com
virtual_alias_maps = hash:/etc/postfix/virtual
Setup Ethernet Bonding on RHEL 6
Scenario: Configure 4 ethernet into 2 ethernet bond0 and bond1 on RHEL 6/CentOS 6.
System: RHEL 6.9
Steps:
1) Create new file bond0 (Eth0+Eth1) with IP Address = 172.16.10.70
# vi /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
IPADDR=172.16.10.70
NETMASK=255.255.255.0
TYPE=Bond
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
USERCTL=no
PEERDNS=yes
IPV6INIT=no
Clone CentOS 6/RHEL 6 VM template using Clonezilla
Scenario:
Clone RHEL 6 VM template to NFS server using Clonezilla for deploy to physical server.
System included:
– Clonezilla iso.
– RHEL 6 VM Template.
– Windows server 2012 R2 NFS server.
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Command to re-read new VM disk CentOS/RHEL
System: CentOS/RHEL 6 and CentOS/RHEl 7
Case:
Added new VM disk in CentOS not showing the new VM disk when run fdisk -l.
Resolution:
Login as root, run this command to re-read the new VM disk without reboot the server.
ls /sys/class/scsi_host/ | while read host ; do echo "- - -" > /sys/class/scsi_host/$host/scan ; done