Red Hat Enterprise Linux (RHEL) 7 and CentOS 7edit

The following instructions show you how to prepare your hosts on Red Hat Enterprise Linux (RHEL) 7 or later and on CentOS 7 or later.

If you want to install Elastic Cloud Enterprise on own hosts, the steps for preparing your hosts can take a bit of time. There are two ways you can approach this:

  • Think like a minimalist: Install the correct version of Docker on hosts that meet the prerequisites for Elastic Cloud Enterprise, then skip ahead and install Elastic Cloud Enterprise. This approach is similar to the Quick Start Guide. Be aware that some checks during the installation can fail with this approach, which will mean doing further host preparation work before retrying the installation.
  • Cover your bases: If you want to make absolutely sure that your installation of Elastic Cloud Enterprise can succeed on hosts that meet the prerequisites, or if any of the checks during the installation failed previously, run through the full preparation steps in this section and then and install Elastic Cloud Enterprise. You’ll do a bit more work now, but life will be simpler later on.

Regardless of which approach you take, the steps in this section need to be performed on every host that you want to use with Elastic Cloud Enterprise.

Install a Supported Linux Kerneledit

Elastic Cloud Enterprise requires 3.10 or higher. The steps shown here install kernel 4.4.

  1. Add the repository required to obtain the kernel:

    sudo yum install -y yum-plugin-fastestmirror
    sudo yum makecache fast
  2. Install kernel version 3.10 or higher from the repository:

    sudo yum --enablerepo=elrepo-kernel install -y kernel-lt
  3. Update the /etc/default/grub file with the required options:

    sudo sed -i -e 's|^GRUB_CMDLINE_LINUX=\(.*\)|GRUB_CMDLINE_LINUX=\"crashkernel=auto rhgb quiet console=ttyS0 cgroup_enable=memory swapaccount=1 cgroup.memory=nokmem\"|g' /etc/default/grub
  4. Enable the overlay kernel module:

    echo "overlay" | sudo tee -a /etc/modules-load.d/overlay.conf
  5. Refresh the dynamically generated grub2 configuration and configure grub to boot the newly installed kernel 3.10 or higher:

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

Install Docker Version 1.11edit

  1. Recommended: Add the Docker repository to make installing the correct version of Docker easier:

    sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
    name=Docker Repository
    sudo yum makecache fast
  2. Install the correct version of the docker-engine package:

    sudo yum install docker-engine-1.11*

Recommended: Set Up XFS quotasedit

Elastic Cloud Enterprise can run without XFS quotas, but they are required to support disk space quotas for Elasticsearch data directories. Some Linux distributions such as RHEL and CentOS already provide XFS as the default file system; however, quotas might be disabled.

Disk space quotas set a limit on the amount of disk space a cluster node can use. Currently, quotas are calculated by a static ratio of 1:32, which means that for every 1 GB of RAM a cluster is given, a cluster node is allowed to consume 32 GB of disk space.

Using LVM, mdadm, or a combination of the two for block device management is possible, but the configuration is not covered here, nor is it provided as part of supporting Elastic Cloud Enterprise.

To set up XFS with quotas on a single, pre-partitioned block device named /dev/xvdg1:

  1. Format the partition:

    sudo mkfs.xfs /dev/xvdg1
  2. Create the /mnt/data/ directory as a mount point:

    sudo install -o $USER -g $USER -d -m 700 /mnt/data
  3. Modify the entry for the XFS volume in the /etc/fstab file to add pquota,prjquota. The default filesystem path used by Elastic Cloud Enterprise is /mnt/data.

    /dev/xvdg1	/mnt/data	xfs	defaults,nofail,x-systemd.automount,prjquota,pquota  0 2
  4. Regenerate the mount files:

    sudo systemctl daemon-reload
    sudo systemctl restart

Update the Configurations Settingsedit

  1. Stop the Docker service:

    sudo systemctl stop docker
  2. 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
  3. 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:

    1. Update the /etc/sysctl.conf file to include this line:

      fs.may_detach_mounts = 1
  4. 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:

    1. Update the /etc/sysctl.conf file to include this line:

      net.ipv4.ip_forward = 1
    2. Restart the network service:

      sudo service network restart
    3. Verify that the change is applied:

      cat /proc/sys/net/ipv4/ip_forward

      The output 1 indicates that IPv4 forwarding is turned on.

  5. 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
  6. If you did not create the mount point earlier (if you did not set up XFS), create the /mnt/data/ directory as a mount point:

    sudo install -o $USER -g $USER -d -m 700 /mnt/data
  7. If you set up a new device with XFS earlier:

    1. Mount the block device (change the device name if you use a different device than /dev/xvdg1):

      sudo mount /dev/xvdg1
    2. Set the permissions on the newly mounted device:

      sudo chown $USER:$USER /mnt/data
  8. Create the /mnt/data/docker directory for the Docker service storage:

    sudo install -o $USER -g $USER -d -m 700 /mnt/data/docker
  9. 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
  10. Configure the Docker daemon options.

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

    Description=Docker Service
    ExecStart=/usr/bin/docker daemon -g /mnt/data/docker --storage-driver=overlay --bip=
  11. Apply the updated Docker daemon configuration:

    Reload the Docker daemon configuration:

    sudo systemctl daemon-reload

    Restart the Docker service:

    sudo systemctl restart docker

    Enable Docker to start on boot:

    sudo systemctl enable docker
  12. Enable your user to communicate with the Docker subsystem by adding it to the docker group:

    sudo usermod -aG docker $USER
  13. 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
  14. Pin the Docker version to ensure that the docker-engine package does not get upgraded:

    echo "exclude=docker-engine" | sudo tee -a /etc/yum.conf
  15. Reboot your system to ensure that all configuration changes take effect:

    sudo reboot
  16. 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.

  17. Repeat these steps on other hosts that you want to use with Elastic Cloud Enterprise or follow the steps in the next section to start installing Elastic Cloud Enterprise.