capsul-flask/capsulflask/shell_scripts/capacity-avaliable.sh

#!/bin/sh
#
# check available RAM and IPv4s

RAM_BYTES_TO_ALLOCATE="$1"
RAM_BYTES_AVAILABLE=$(grep -E "^(size|memory_available_bytes)" /proc/spl/kstat/zfs/arcstats | awk '{sum+=$3} END {printf "%.0f", sum}')
RAM_BYTES_REMAINDER="$((RAM_BYTES_AVAILABLE - RAM_BYTES_TO_ALLOCATE))"

if echo "$RAM_BYTES_TO_ALLOCATE" | grep -vqE "^[0-9]+$"; then 
  echo "RAM_BYTES_TO_ALLOCATE \"$RAM_BYTES_TO_ALLOCATE\" must be an integer"
  exit 1
fi

# I picked 10GB arbitrarily
if [ "$RAM_BYTES_REMAINDER" -le $((10 * 1024 * 1024 * 1024)) ]; then
  echo "VM is requesting more RAM than $(hostname -f) has available."
  echo "Bytes requested: $RAM_BYTES_TO_ALLOCATE"
  echo "Bytes available: $RAM_BYTES_AVAILABLE"
  exit 1
fi

IPV4_LIMIT=60
IPV4_COUNT=$(grep ip-add /var/lib/libvirt/dnsmasq/virbr2.status | wc -l)

if [ "$IPV4_COUNT" -ge "$IPV4_LIMIT" ]; then
  echo "IPv4 address limit reached"
  exit 1
fi
 
echo "yes"