ec2 format and mount ephemeral instance store disks

ec2-instance-store-init.sh

#!/bin/bash

#set -e
#set -o pipefail

###
# This script will strip together all disk to create a raid device at /dev/md0
# EC2 instances with a single instance store disk will instead use the raw nvme device
#
# Requires these packages: lvm2 jq mdadm nvme-cli
###

# Configure stuff here
VGNAME=EphemeralData

VOL1_MOUNTPOINT=/sastmp/saswork
VOL1_LVNAME=saswork

VOL2_MOUNTPOINT=/sastmp/sascache
VOL2_LVNAME=sascache


### No need to modify anything after this line

# Get a list of ephemeral storage devices using the nvme cli
DEVLIST=$(nvme list --output-format=json | jq -r '.Devices | to_entries[] | .value | select(.ModelNumber == "Amazon EC2 NVMe Instance Storage") | .DevicePath')

# Get a count of those devices
NUMDEV=$(echo $DEVLIST | wc -w)

if [ $NUMDEV -eq 0 ]
then
  # No ephermal storage devices found.  We're going to have the script exit as there is nothing to do here.
  echo "no ephemeral devices found"
        mkdir -p $VOL1_MOUNTPOINT
        mkdir -p $VOL2_MOUNTPOINT
        exit
elif [ $NUMDEV -eq 1 ]
then
    # Simply use the single device we have.  Don't bother making a RAID out of it
    DEVICE=$DEVLIST
else
    # Create a raid device using the disks we were provided.
        if [ -b /dev/md0 ]
        then
            print "Raid already exists, skipping..."
        else
            yes | mdadm --create /dev/md0 --level=stripe --raid-devices=$NUMDEV $DEVLIST
        fi
        DEVICE=/dev/md0
fi

WARNING='This filesystem is ephemeral.  It WILL be deleted when this EC2 instance is stopped or restarted.  DO NOT STORE IMPORTANT INFORMATION ON THIS VOLUME!'

# Create a tempdata volume group
if vgdisplay | grep -q $VGNAME; then
    echo "Volume Group $VGNAME exists, skipping...."
else
    vgcreate $VGNAME $DEVICE
fi

if [ -b /dev/$VGNAME/$VOL1_LVNAME ]
then
    echo "/dev/$VGNAME/$VOL1_LVNAME exists, skipping...."
else
    lvcreate -L 100G -n $VOL1_LVNAME $VGNAME
    if [ $? -ne 0 ]
    then
        echo "failed to create $VGNAME"
        exit 10
    fi
    mkfs.xfs /dev/$VGNAME/$VOL1_LVNAME
    mkdir -p $VOL1_MOUNTPOINT
fi

if mountpoint -q $VOL1_MOUNTPOINT
then
    echo "$VOL1_MOUNTPOINT already mounted, skipping..."
else
    mount /dev/$VGNAME/$VOL1_LVNAME $VOL1_MOUNTPOINT
    echo $WARNING > $VOL1_MOUNTPOINT/WARNING_README.txt
fi

if [ -b /dev/$VGNAME/$VOL2_LVNAME ]
then
    echo "/dev/$VGNAME/$VOL2_LVNAME exists, skipping...."
else
    lvcreate -l 100%FREE -n $VOL2_LVNAME $VGNAME
    if [ $? -ne 0 ]
    then
        echo "failed to create $VGNAME"
        exit 10
    fi
    mkfs.xfs /dev/$VGNAME/$VOL2_LVNAME
    mkdir -p $VOL2_MOUNTPOINT
fi

if mountpoint -q $VOL2_MOUNTPOINT
then
    echo "$VOL2_MOUNTPOINT already mounted, skipping..."
else
    mount /dev/$VGNAME/$VOL2_LVNAME $VOL2_MOUNTPOINT
    echo $WARNING > $VOL2_MOUNTPOINT/WARNING_README.txt
fi