mc-cheap

userscript.sh

#!/bin/bash -xe
#
# See: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-using-volumes.html
#
# Make sure both volumes have been created AND attached to this instance !
#
# We do not need a loop counter in the "until" statements below because
# there is a 5 minute limit on the CreationPolicy for this EC2 instance already.

EC2_INSTANCE_ID=$(curl -s http://instance-data/latest/meta-data/instance-id)
EC2_VOLUME_ID="vol-009aa0da0297b5c25"
region=$(curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone | sed -e 's/.$//')

MC_VERSION="1.15.1"


######################################################################
# Volume /dev/sdh (which will get created as /dev/xvdh on Amazon Linux)

aws ec2 attach-volume --device /dev/sdh --region ${region} \
  --instance-id ${EC2_INSTANCE_ID} --volume-id vol-009aa0da0297b5c25

DATA_STATE="unknown"
until [ "${DATA_STATE}" == "attached" ]; do
  DATA_STATE=$(aws ec2 describe-volumes \
    --region ${region} \
    --filters \
        Name=attachment.instance-id,Values=${EC2_INSTANCE_ID} \
        Name=attachment.device,Values=/dev/sdh \
    --query Volumes[].Attachments[].State \
    --output text)

  sleep 5
done

# Format /dev/xvdh if it does not contain a partition yet
if [ "$(file -b -s /dev/sdh)" == "data" ]; then
  mkfs -t ext4 /dev/sdh
fi

mkdir -p /minecraft
mount /dev/sdh /minecraft

if test ! -d /minecraft/server; then
  mkdir -p /minecraft/server
fi

chown -R ec2-user:ec2-user /minecraft

# Persist the volume in /etc/fstab so it gets mounted again
echo '/dev/sdh /minecraft ext4 defaults,nofail 0 2' | sudo tee -a /etc/fstab

docker run -d -it \
  -e EULA=TRUE -e VERSION=${MC_VERSION} -e INIT_MEMORY=1G -e MAX_MEMORY=16G \
  -p 25565:25565 \
  -v /minecraft/server:/data \
  --log-driver=awslogs \
    --log-opt awslogs-region=ap-northeast-1 \
    --log-opt awslogs-group=mc-cheap \
    --log-opt awslogs-stream=minecraft \
  --name mc \
  itzg/minecraft-server

# set route53

R53_ZONE_NAME=mc.naari3.net.
R53_HOSTNAME=mcserver
HOSTED_ZONEID=/hostedzone/Z3GZ6G254FYNY3

R53_CALLER="${R53_ZONE_NAME}-`date +%Y%m%d-%H%M%S`"
R53_COMMENT="dynamic dns record set"
MY_DDNS_RECORD=${R53_ZONE_NAME}

MY_PUBLIC_IP=`curl -s ifconfig.me`
if [ -z $MY_PUBLIC_IP ] ;  then
    echo "failed to get global IP address"
    exit 1
fi
cat <<EOT > /tmp/recordset.json
{
  "Comment": "create A record",
  "Changes": [
    {
      "Action": "UPSERT",
      "ResourceRecordSet": {
        "Name": "${MY_DDNS_RECORD}",
        "Type": "A",
        "TTL": 60,
        "ResourceRecords": [
         {
           "Value": "${MY_PUBLIC_IP}"
         }
        ]
      }
    }
  ]
}
EOT

aws route53 change-resource-record-sets --hosted-zone-id $HOSTED_ZONEID --change-batch file:///tmp/recordset.json

rm -rf /tmp/recordset.json

# players check

cat << 'BASH' > /server_players_check.sh
#!/bin/bash -xe

player_count=$(docker exec mc bash -c "if [[ \`mcstatus localhost status | grep players:\` =~ ^players:\ ([0-9]+) ]]; then
  count=\${BASH_REMATCH[1]};
  echo \$count;
fi")

if [ ${player_count} == "0" ]; then
  if test -e /tmp/until_no_man; then
    aws autoscaling update-auto-scaling-group --region=ap-northeast-1 --auto-scaling-group-name=mc-cheap --desired-capacity=0
  else
    touch /tmp/until_no_man
  fi
else
  rm -f /tmp/until_no_man
fi
BASH

chmod +x /server_players_check.sh

echo "*/15 * * * * /server_players_check.sh" > /tmp/rootcron
crontab -u root /tmp/rootcron
rm /tmp/rootcron

# create tag

aws ec2 create-tags --resources ${EC2_INSTANCE_ID} --tags Key=minecraft-status,Value=starting --region ${region}

cat << BASH > /minecraft_server_status_check.sh
#!/bin/bash -xe

while true; do
  status=\$(if [[ \`docker ps -f "name=mc" --format "{{.Status}}"\` =~ \\((.+?)\\) ]]; then
    status=\${BASH_REMATCH[1]};
    echo \$status;
  fi)

  if [ "\${status}" == "healthy" ]; then
    aws ec2 create-tags --resources ${EC2_INSTANCE_ID} --tags Key=minecraft-status,Value=healthy --region ${region}
  fi

  sleep 10s
done
BASH
chmod +x /minecraft_server_status_check.sh

bash /minecraft_server_status_check.sh &