mkpartitions

#!/usr/bin/env bash

##################################################
#### Wipe device, then partition with several same-sized partitions
##################################################

##################################################
#### partname is not optional, the way this script invokes parted
#### specifying too many or too large partitions results in fewer created

partcount=10
partgb=5
partname=iscsi
device=/dev/nvme0n1xxx
createremainder=0
uniquesuffix=0



##################################################
#### SCRIPT BEGIN
##################################################

echo "Checking device..."
[[ -b "${device}" ]] || { echo "ERROR: ${device} invalid"; exit 1; }

{ lsblk -l "${device}" | awk -v device=$(basename "${device}") '$1 == device && $6 !~ /disk/ {print "ERROR: /dev/" device " is a " $6", not a disk"; exit 1}'; } || exit 1


### note wipefs and parted both seem to refuse
### reasonable endeavor check anyway

echo "Checking mounts..."
{ lsblk -l "${device}" | awk -v device=$(basename "${device}") '$1 ~ device && $7 ~ /\// {print "ERROR: mounted at "$7; exit 1}'; } || exit 1


if ! command -v pvs &> /dev/null
then
   echo "Skipping LVM check..."
else
   echo "Checking LVM..."
   for i in $(lsblk -l "${device}" | awk -v device=$(basename "${device}") '$1 ~ device {print $1}'); do
       { pvs | awk -v checkpv="/dev/${i}" '$1 == checkpv {print "ERROR: LVM uses "$1; exit 1}'; } || exit 1
done
fi


echo
read -t 2 -r -n 2 -s -p "Press any key to wipe ${device} and re-partition with ${partcount} * ${partgb}GiB partitions " || { echo -e "\nTimed out"; exit 1; }
echo

echo
echo -n "Continuing in a few seconds..."
for i in {1..3}; do echo -n .; sleep "${i}"; done; echo -en '.\n'


echo "Wiping..."
for i in $(lsblk -l "${device}" | awk '$6 ~/^part$/ {print $1}'); do
   wipefs -a /dev/"${i}" > /dev/null ||
   { echo "ERROR: partition ${device} not wiped"; exit 1; }
done

wipefs -a "${device}" > /dev/null ||
{ echo "ERROR: device ${device} not wiped"; exit 1; }


echo "Partitioning..."

### try to be balanced
generate_uniq_suffix() {
  if [[ "${uniquesuffix}" -ne 0 ]]; then
       [[ -z "${mid}" ]] &&
       [[ -f /etc/machine-id ]] &&
           mid=$(</etc/machine-id)
       [[ -z "${mid}" ]] &&
           mid="${RANDOM:0:4}${RANDOM:0:4}"
       echo "$(date +%s%N)${mid}${device}" |
           cksum |
           cut -d ' ' -f1
   fi
}

parted --align=optimal "${device}" --script -- \
$(echo "'mklabel gpt'") \
$(echo "'mkpart ${partname}$(generate_uniq_suffix) 0% ${partgb}GiB'") \
$(for i in $(seq 1 $(("${partcount}"-1))); do
   echo -e "'mkpart ${partname}$(generate_uniq_suffix) $(( $i*${partgb} ))GiB $(( $i*${partgb}+${partgb} ))GiB'"
done)
echo "mkpart ${partname} exit: $?"

if [[ "${createremainder}" -eq 1 ]]; then
   echo "Partitioning extra space (will fail if number requested not created)..."
   extraargs=$(echo "'mkpart extra$(generate_uniq_suffix) $(( ${partgb}*${partcount} ))GiB 100%'")
   parted --align=optimal "${device}" --script -- \
   $(echo "${extraargs}")
   echo "mkpart extra softexit: $?"
fi


echo
echo "Final state:"
parted --align=optimal "${device}" p | grep --color=always '$\|[[:space:]]extra[0-9]*$'