how to resize/expand a LVM partition on a GPT partition table in CentOS 6

Some dummy somewhere removed the 'resize' command from `parted`. But this old version didn't work with LVM partition types anyway. You need parted 3.2

# yum install device-mapper-devel readline-devel libuuid-devel
# mkdir /opt/parted
# cd /opt/parted
# wget "https://ftp.gnu.org/gnu/parted/parted-3.2.tar.xz"
# tar xJvf parted-3.2.tar.xz
# cd parted-3.2
# ./configure
# make
# ./parted/parted /dev/sda
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
Model: AMCC 9650SE-8LP DISK (scsi)
Disk /dev/sda: 10000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  211MB   210MB   ext3               boot, esp
 2      211MB   8000GB  8000GB                     lvm

(parted) resizepart 2 100%
Error: Partition(s) 2 on /dev/sda have been written, but we have been unable to inform the kernel of the change, probably because it/they are in use.  As a result, the old partition(s)
will remain in use.  You should reboot now before making further changes.
Ignore/Cancel? I
(parted) p
Model: AMCC 9650SE-8LP DISK (scsi)
Disk /dev/sda: 10000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End      Size     File system  Name  Flags
 1      1049kB  211MB    210MB    ext3               boot, esp
 2      211MB   10000GB  10000GB                     lvm

(parted) q

now reboot

# pvresize /dev/sda2
  Physical volume "/dev/sda2" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized