Convert ECS Optimized AMI to use overlay/overlay2

overlay.sh

set -e

# Stop the docker daemon
/etc/init.d/docker stop

# Configure ECS Agent
# http://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-agent-config.html
# http://docs.aws.amazon.com/AmazonECS/latest/developerguide/automated_image_cleanup.html
cat > /etc/ecs/ecs.config << "EOF"
ECS_ENGINE_TASK_CLEANUP_WAIT_DURATION=1h
ECS_NUM_IMAGES_DELETE_PER_CYCLE=100
EOF

# Install some packages
yum update -y
yum install -y vim-enhanced curl wget epel-release

# Needed for docker's completion
yum install -y bash-completion --enablerepo=epel

# The current AMI uses 17.03.1-ce, so no need to upgrade anymore.
# Keeping this to show how to upgrade in the future.
# 
# Upgrade to Docker 17.03.1-ce
# wget https://get.docker.com/builds/Linux/x86_64/docker-17.03.1-ce.tgz
# tar xzf docker-17.03.1-ce.tgz
# cp docker/docker* /usr/bin
# cp docker/completion/bash/docker /etc/bash_completion.d/
# rm -rf docker*

# Use good ole port 4242 for ssh
sed -i 's/#Port 22/Port 4242/' /etc/ssh/sshd_config

# Get rid of devicemapper defs
dmsetup remove_all

# Reset the disk
dd if=/dev/zero of=/dev/xvdcz bs=512 count=128

# Remove all docker data
rm -rf /var/lib/docker/*

# Remove ecs data
rm -rf /var/lib/ecs/data/* /var/cache/ecs/*

# Remove cloud-init stuff so that it runs again
rm -rf /var/lib/cloud/*

# Remove logs
rm -rf /var/log/cloud-init* /var/log/docker /var/log/ecs/*

# Don't need this
cat > /etc/sysconfig/docker-storage-setup << "EOF"
echo "Not needed with overlay, contents removed"
exit 1
EOF

# Setup docker to use overlay
cat > /etc/sysconfig/docker-storage << "EOF"
DOCKER_STORAGE_OPTIONS="--storage-driver=overlay"
EOF

# Setup cloud init to prep disks for docker to use overlay
cat > /etc/cloud/cloud.cfg.d/90_ecs.cfg << "EOF"
#cloud-config

cloud_init_modules:
  - bootcmd

cloud_config_modules:
  - mounts

system_info:
  default_user:
    groups: [ "wheel", "docker" ]

bootcmd:
  - [ cloud-init-per, once, docker_overlay_fs, mkfs, -t, ext4, -L, docker, -i, 4096, /dev/xvdcz ]

# This doesn't seem to work, hence using the bootcmd above instead.
# fs_setup:
#  - label: docker
#    filesystem: ext4
#    device: /dev/xvdcz
#    partition: none
#    cmd: mkfs -t %(FILESYSTEM)s -L %(LABEL)s -i 4096 %(DEVICE)s

mounts:
  - [ /dev/xvdcz, /var/lib/docker/overlay ]
EOF