How to extend partition linux parted

Question

Context

I have a remote Linux CentOS VM on Azure which hosts a MYSQL database. I just finished upgrading the disk size from 30GB to 100GB. Problem is that extra space wasn't added to the partition.

$ parted

(parted) print free
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system     Flags
        32.3kB  1049kB  1016kB           Free Space
 1      1049kB  31.2GB  31.2GB  primary  ext4            boot
 2      31.2GB  32.2GB  1049MB  primary  linux-swap(v1)
        32.2GB  107GB   75.2GB           Free Space

$ lsblk

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
fd0      2:0    1    4K  0 disk
sda      8:0    0  100G  0 disk
├─sda1   8:1    0   29G  0 part /
└─sda2   8:2    0 1000M  0 part
sdb      8:16   0   50G  0 disk
└─sdb1   8:17   0   50G  0 part /mnt/resource

$ df

Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/sda1       29822848 25241412   3043440  90% /
devtmpfs         1752756        0   1752756   0% /dev
tmpfs            1761624        0   1761624   0% /dev/shm
tmpfs            1761624     8440   1753184   1% /run
tmpfs            1761624        0   1761624   0% /sys/fs/cgroup
/dev/sdb1       51472864    53276  48781868   1% /mnt/resource
tmpfs             352328        0    352328   0% /run/user/1000

Question

Obviously, I need to extend partition 1 (/dev/sda) to include the free space. Using this post, I tried

sudo resize2fs /dev/sda 100G

but it gets rejected with

Device or resource busy while trying to open /dev/sda`.

I think this means that I can't extend the partition while it's in use, which makes sense to me given my experience doing the same on windows. If that is the case, then how do I extend the partition on a remote azure VM?

Note: I only shell into the VM, therefore I cannot boot an external program, use a GUI, or simply mount the drive onto another machine.

OS Details

  Static hostname: PMCTMYSQL
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 99f30b6b81444d47a888f0313c428bd8
           Boot ID: 444cc3a5a22b4e53a947e06af2d9b4d2
    Virtualization: microsoft
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-327.36.3.el7.x86_64
      Architecture: x86-64

More Research

I checked other threads suggested by SU, but they don't apply for a variety of reasons:

Suggests GUI tools

1. How to extend partition size in linux(ubuntu 9.04)?
2. How to extend a Linux ext3 partition?
3. How to extend a Mint Linux partition on a dual boot config with Windows 8.1?
4. How to resize extended partition?

Uses VMware

1. How to extend partition size in linux(ubuntu 9.04)?

Uses external tools (boot disk) How to Extend primary partition(/dev/sda1) in linux?

1. https://www.howtoforge.com/linux_resizing_ext3_partitions

Solution

You can use Gparted, as you are using centOS you can install it by:

yum install epel-release
yum install gparted

Here is some information on how to use it:

http://gparted.org/display-doc.php%3Fname%3Dmoving-space-between-partitions