Resize Filesystem Without Reboot

1. Toggle some informations about the root filesystem: 
 df /
# Filesystem 1K-blocks Used Available Use% Mounted on
# /dev/vda3 71412992 58923184 9039732 87% / 
 2. /dev/vda3  is the second partition of block device  /dev/vda . To size up this partition, you can use the tool  parted . 
 parted /dev/vda resizepart 3 100%
# Warning: Partition /dev/sda2 is being used. Are you sure you want to continue?
# Yes/No? yes
# Information: You may need to update /etc/fstab. 
 3. After changing size of partition, you have to size up the filsystem too: 
 resize2fs /dev/vda3
# resize2fs 1.45.5 (07-Jan-2020)
# Filesystem at /dev/vda3 is mounted on /; on-line resizing required
# old_desc_blocks = 4, new_desc_blocks = 9
# The filesystem on /dev/vda3 is now 18019403 (4k) blocks long. 
 4. This is for checking modifications: 
 df /
# Filesystem 1K-blocks Used Available Use% Mounted on
# /dev/vda3 70817420 5253016 62349464 8% /