Add the repository required to obtain the kernel:

yum update
reboot

Add the required options to the kernel boot arguments:

sudo /sbin/grubby --update-kernel=ALL --args='cgroup_enable=memory cgroup.memory=nokmem swapaccount=1'

Enable the overlay kernel module:

echo "overlay" | sudo tee -a /etc/modules-load.d/overlay.conf

Refresh the dynamically generated grub2 configuration and configure grub to boot the newly installed kernel 3.10 or higher:

sudo grub2-set-default 0
sudo grub2-mkconfig -o /etc/grub2.cfg

Add the Docker repository:

sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://download.docker.com/linux/centos/7/x86_64/stable
enabled=1
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
EOF

sudo yum makecache fast

Install the latest version of docker-ce:

sudo yum install docker-ce-18.09.2*

Stop the Docker service:

sudo systemctl stop docker

If you plan to run Elasticsearch 5.0 and later: Update the /etc/sysctl.conf file to set the maximum number of mapped memory areas a process can have:

echo "vm.max_map_count=262144" | sudo tee -a /etc/sysctl.conf

For RHEL only: Verify that fs.may_detach_mounts is enabled:

cat /proc/sys/fs/may_detach_mounts

If the output of this command is not 1, you must enable the setting in order for Docker to cleanly remove containers:

Verify that IPv4 forwarding is enabled:

cat /proc/sys/net/ipv4/ip_forward

If the output of this command is not 1, you must enable IPv4 forwarding so that Docker can work as expected:

Adjust the system limits.

Add the following configuration values to the /etc/security/limits.conf file. These values are derived from our experience with the Elastic Cloud hosted offering and should be used for Elastic Cloud Enterprise as well.

If you are using a user name other than elastic, adjust the configuration values accordingly.

*                soft    nofile         1024000
*                hard    nofile         1024000
*                soft    memlock        unlimited
*                hard    memlock        unlimited
elastic          soft    nofile         1024000
elastic          hard    nofile         1024000
elastic          soft    memlock        unlimited
elastic          hard    memlock        unlimited
root             soft    nofile         1024000
root             hard    nofile         1024000
root             soft    memlock        unlimited

Create the /mnt/data/ directory as a mount point:

sudo install -o $USER -g $USER -d -m 700 /mnt/data

Create the /mnt/data/docker directory for the Docker service storage:

sudo install -o $USER -g $USER -d -m 700 /mnt/data/docker

Disable the firewalld service. The service is not compatible with Docker and interferes with the installation of ECE. You must disable firewalld before installing or reinstalling ECE.

sudo systemctl disable firewalld

Update the /etc/systemd/system/docker.service.d/docker.conf file. If the file path and file do not exist, create them.

[Unit]
Description=Docker Service
After=multi-user.target

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd --data-root /mnt/data/docker --storage-driver=overlay --bip=172.17.42.1/16

Apply the updated Docker daemon configuration:

Enable your user to communicate with the Docker subsystem by adding it to the docker group:

sudo usermod -aG docker $USER

Recommended: Tune your network settings.

Create a 70-cloudenterprise.conf file in the /etc/sysctl.d/ file path that includes these network settings:

cat << SETTINGS | sudo tee /etc/sysctl.d/70-cloudenterprise.conf
net.ipv4.tcp_max_syn_backlog=65536
net.core.somaxconn=32768
net.core.netdev_max_backlog=32768
SETTINGS

Pin the Docker version to ensure that the docker-ce package does not get upgraded:

echo "exclude=docker-ce" | sudo tee -a /etc/yum.conf

Reboot your system to ensure that all configuration changes take effect:

sudo reboot

After rebooting, verify that your Docker settings persist as expected:

sudo docker info | grep Root

If the command returns Docker Root Dir: /mnt/data/docker, then your changes were applied successfully and persist as expected.

If the command returns Docker Root Dir: /var/lib/docker, then you need to troubleshoot the previous configuration steps until the Docker settings are applied successfully before continuing with the installation process. For more information, see Custom Docker daemon options in the Docker documentation.