Configure an Ubuntu host

The following instructions show you how to prepare your hosts on Ubuntu.

• Install Docker
• Set up XFS quotas
• Update the configurations settings
• Configure the Docker daemon options

Install a compatible Docker version on Ubuntu.

1. Install the Docker repository dependencies:

   sudo apt-get install ca-certificates curl gnupg lsb-release
   		

2. Add Docker’s official GPG key:

   sudo mkdir -m 0755 -p /etc/apt/keyrings
   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
   		

3. Add the stable Docker repository:

   echo \
     "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
     $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
   		

4. Install the correct version of the docker-ce package. The following is an example of installing Docker 27.0. If you decide to install a different Docker version, make sure to replace with the desired version in the commands below.

   sudo apt update && sudo apt install -y docker-ce=5:27.0.* docker-ce-cli=5:27.0.* containerd.io
   		

XFS is required to support disk space quotas for Elasticsearch data directories. Some Linux distributions such as RHEL and Rocky Linux already provide XFS as the default file system. On Ubuntu, you need to set up an XFS file system and have quotas enabled.

Disk space quotas set a limit on the amount of disk space an Elasticsearch 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.

Example: Set up XFS 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. Add an entry to the /etc/fstab file for the new XFS volume. 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 local-fs.target
   		

1. Stop the Docker service:

   sudo systemctl stop docker
   		

2. Enable cgroup accounting for memory and swap space.

   1. In the /etc/default/grub file, ensure that the GRUB_CMDLINE_LINUX= variable includes these values:

      cgroup_enable=memory swapaccount=1 cgroup.memory=nokmem
      		

   2. Update your Grub configuration:

      sudo update-grub
      		

3. Configure kernel parameters

   cat <<EOF | sudo tee -a /etc/sysctl.conf
   # Required by Elasticsearch
   vm.max_map_count=1048576
   # enable forwarding so the Docker networking works as expected
   net.ipv4.ip_forward=1
   # Decrease the maximum number of TCP retransmissions to 5 as recommended for Elasticsearch TCP retransmission timeout.
   # See https://www.elastic.co/guide/en/elasticsearch/reference/current/system-config-tcpretries.html
   net.ipv4.tcp_retries2=5
   net.netfilter.nf_conntrack_tcp_timeout_established=7200
   net.netfilter.nf_conntrack_max=262140
   # Make sure the host doesn't swap too early
   vm.swappiness=1
   EOF
   		

   Important

   The net.ipv4.tcp_retries2 setting applies to all TCP connections and affects the reliability of communication with systems other than Elasticsearch clusters too. If your clusters communicate with external systems over a low quality network then you may need to select a higher value for net.ipv4.tcp_retries2.

   Note

   According to Elasticsearch networking settings, Elasticsearch overrides TCP keepalive settings at the socket level for its own connections:

   • If system-level values exceed 300 seconds, Elasticsearch automatically lowers them to 300 seconds.
   • Values below 300 seconds are used as-is.

   For non-Elasticsearch connections such as the proxy layer, consider reducing the following TCP keepalive parameters to detect stale network sessions and prevent firewalls from dropping silent connections:

   • net.ipv4.tcp_keepalive_time
   • net.ipv4.tcp_keepalive_intvl
   • net.ipv4.tcp_keepalive_probes

   1. Apply the settings:

      sudo sysctl -p
      		

4. 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.

   Tip

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

5. NOTE: This step is optional if the Docker registry doesn’t require authentication.

   Authenticate the elastic user to pull images from the Docker registry you use, by creating the file /home/elastic/.docker/config.json. This file needs to be owned by the elastic user. If you are using a user name other than elastic, adjust the path accordingly.

   Example: In case you use docker.elastic.co, the file content looks like as follows:

   {
    "auths": {
      "docker.elastic.co": {
        "auth": "<auth-token>"
      }
    }
   }
   		

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 /mnt/data
      		

   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
   		

Docker daemon configuration can be defined in multiple ways. In this guide, Docker is configured using both the daemon configuration file (/etc/docker/daemon.json) and a systemd service override. The daemon.json file defines runtime settings for the Docker daemon, while the systemd configuration controls how the daemon is started and which command-line flags are applied.

For more information, refer to the Docker daemon configuration overview.

1. Create the /etc/docker directory if it does not exist, then create or update the /etc/docker/daemon.json file with the following configuration:

   {
     "default-ulimits": {
       "nofile": {
         "Name": "nofile",
         "Soft": 1048576,
         "Hard": 1048576
       }
     }
   }
   		

   This configuration increases the maximum number of open file descriptors available to Docker containers.

2. Create the /etc/systemd/system/docker.service.d directory if it does not exist, then create or update the /etc/systemd/system/docker.service.d/docker.conf file with the following configuration:

   [Unit]
   Description=Docker Service
   After=multi-user.target
   
   [Service]
   Environment="DOCKER_OPTS=-H unix:///run/docker.sock --data-root /mnt/data/docker --storage-driver=overlay2 --bip=172.17.42.1/16 --raw-logs --log-opt max-size=500m --log-opt max-file=10 --icc=false"
   ExecStart=
   ExecStart=/usr/bin/dockerd $DOCKER_OPTS
   		

   1. You can adjust --log-opt max-size and --log-opt max-file to configure container log rotation settings for the Docker daemon.
   Tip

   Alternatively, you can use sudo systemctl edit docker to create a systemd override file. This command automatically creates the appropriate directory and opens an editor for you to define the override configuration.

   Note

   Docker creates a default bridge network that can conflict with IP ranges used in your internal network. The --bip parameter defines both the bridge IP address and the subnet used by Docker.

   To avoid conflicts, replace the --bip=172.17.42.1/16 parameter in our examples with a subnet that does not overlap with your existing network ranges. If there is no conflict, you can omit the --bip parameter. This setting is local to each host, so the same value can be reused across all hosts in the ECE platform.

   For more information, refer to the dockerd command line reference.

3. Apply the updated Docker daemon configuration.

   1. Reload the Docker daemon configuration:

      sudo systemctl daemon-reload
      		

   2. Restart the Docker service:

      sudo systemctl restart docker
      		

   3. Enable Docker to start on boot:

      sudo systemctl enable docker
      		

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

   sudo usermod -aG docker $USER
   		

5. 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
   		

6. Pin the Docker version to ensure that the package does not get upgraded:

   echo "docker-ce hold" | sudo dpkg --set-selections
   echo "docker-ce-cli hold" | sudo dpkg --set-selections
   echo "containerd.io hold" | sudo dpkg --set-selections
   		

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

   sudo reboot
   		

8. 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, check Docker daemon configuration in the Docker documentation.

9. 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.