#!/bin/bash
# Include as user data during instance startup, or run as root using sudo
# Assumes that you are using an i3 instance type with NVMe instance storage attached

# Set swappiness to zero
sysctl vm.swappiness=0
echo "vm.swappiness = 0" >> /etc/sysctl.conf

# Disable transparent huge pages
cat > /etc/init.d/disable-thp <<- 'EOM'
#!/bin/bash
### BEGIN INIT INFO
# Provides:          disable-thp
# Required-Start:    $local_fs
# Required-Stop:
# X-Start-Before:    couchbase-server docker
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Disable THP
# Description:       disables Transparent Huge Pages (THP) on boot
### END INIT INFO
          
case $1 in
start)
  if [ -d /sys/kernel/mm/transparent_hugepage ]; then
    echo 'never' > /sys/kernel/mm/transparent_hugepage/enabled
    echo 'never' > /sys/kernel/mm/transparent_hugepage/defrag
  elif [ -d /sys/kernel/mm/redhat_transparent_hugepage ]; then
    echo 'never' > /sys/kernel/mm/redhat_transparent_hugepage/enabled
    echo 'never' > /sys/kernel/mm/redhat_transparent_hugepage/defrag
  else
    return 0
  fi
;;
esac
EOM

chmod 755 /etc/init.d/disable-thp
/etc/init.d/disable-thp start
chkconfig disable-thp on

# Mount the ephemeral storage (NVMe SSD instance storage)
mkfs -t ext4 /dev/nvme*n1
mkdir -p /mnt/couchbase
mount -t ext4 /dev/nvme0n1 /mnt/couchbase
echo "/dev/nvme0n1 /mnt/couchbase ext4 defaults,noatime 0 0" | tee -a /etc/fstab
chmod 777 /mnt/couchbase

# Install Docker
yum -y update
yum install docker -y
service docker start

# Install Amazon SSM Agent
cd /tmp
sudo yum install -y https://s3.amazonaws.com/ec2-downloads-windows/SSMAgent/latest/linux_amd64/amazon-ssm-agent.rpm

# Run Couchbase 5.0.0-beta2
docker run -d --name couchbase --network=host --restart=always \
    -v /mnt/couchbase:/opt/couchbase/var \
    --ulimit nofile=100000:100000 --ulimit core=100000000:100000000 --ulimit memlock=100000000:100000000 \
    couchbase/server:5.0.0-beta2