for: https://github.com/tmcallaghan/sysbench-mongodb#requirements script to convert a pem to jks truststore

convert-pem-to-jks.sh

mydir=/home/ec2-user/certs
truststore=${mydir}/rds-truststore.jks
storepassword=sysbench

mkdir /home/ec2-user/certs
curl -sS "https://s3.amazonaws.com/rds-downloads/rds-combined-ca-bundle.pem" > ${mydir}/rds-combined-ca-bundle.pem
awk 'split_after == 1 {n++;split_after=0} /-----END CERTIFICATE-----/ {split_after=1}{print > "rds-ca-" n ".pem"}' < ${mydir}/rds-combined-ca-bundle.pem

for CERT in rds-ca-*; do
  alias=$(openssl x509 -noout -text -in $CERT | perl -ne 'next unless /Subject:/; s/.*(CN=|CN = )//; print')
  echo "Importing $alias"
  keytool -import -file ${CERT} -alias "${alias}" -storepass ${storepassword} -keystore ${truststore} -noprompt
  rm $CERT
done

rm ${mydir}/rds-combined-ca-bundle.pem

echo "Trust store content is: "

keytool -list -v -keystore "$truststore" -storepass ${storepassword} | grep Alias | cut -d " " -f3- | while read alias 
do
   expiry=`keytool -list -v -keystore "$truststore" -storepass ${storepassword} -alias "${alias}" | grep Valid | perl -ne 'if(/until: (.*?)\n/) { print "$1\n"; }'`
   echo " Certificate ${alias} expires in '$expiry'" 
done