Experimenting with mounting EBS volumes in Amazon EC2

user-data.sh

#!/bin/bash

# Mount a volume to the system's `/var` directory. This limits the impact of
# unbounded disk usage for log and database files typically stored there.

set -x

# Redirect the output of all commands in this script to a file in `/root`
exec 1<&-
exec 2<&-
exec 1<>/root/var-mount-log.txt
exec 2>&1

mkfs --type ext4 /dev/xvdg

# Stop services which may have open files in `/var`
systemctl isolate rescue.target
systemctl stop systemd-journald*

# Move the current contents to a temporary directory
mkdir /mnt/var
mv /var/* /mnt/var
mount /dev/xvdg /var
mv /mnt/var/* /var

# Ensure the partition is mounted at startup
echo /dev/xvdg  /var ext4 defaults,nofail 0 2 >> /etc/fstab

# Remove the temporary directory
rmdir /mnt/var

reboot