# Installing Docker UCP and DTR on RHEL VMs

The following playbooks are used to install Docker UCP and DTR on RHEL VMs.

• playbooks/config_storage_driver.yml prepares drives for local Docker volumes and container images. It also configures Docker with either the overlay2 storage driver (the default) or the devicemapper storage driver, depending on the value of the docker_storage_driver variable in group_vars/vars. This playbook was previously called playbooks/config_docker_lvs.yml in earlier releases of the solution.

• playbooks/install_docker.yml installs Docker along with all of its dependencies.

• playbooks/install_rsyslog.yml installs and configures rsyslog in the logger node and in all Docker nodes. The logger node will be configured to receive all syslogs on port 514 and the Docker nodes will be configured to send all logs (including container logs) to the logger node.

• playbooks/docker_post_config.yml performs a variety of tasks to complete the installation of the Docker environment, including configuration of the HTTP/HTTPS proxies, if any, and installation of the VMware vSphere Storage for Docker volume plugin.

• playbooks/install_nfs_server.yml installs and configures an NFS server on the NFS node.

  This playbook has been updated to configure a third drive which is used to hold the data of the persistent volumes created with the NFS provisioner. This default size for this drive is purposefully kept small because using the NFS VM to store persistent volumes is not recommended for production use. However, this can be useful for demo purposes.

• playbooks/install_nfs_clients.yml installs the required packages on the Docker nodes to be able to mount an NFS share.

• playbooks/create_main_ucp.yml installs and configures the first Docker UCP instance on the target node defined by the group ucp_main in the vm_hosts inventory.

• playbooks/scale_ucp.yml installs and configures additional instances of UCP on the target nodes defined by the group ucp in the vm_hosts inventory, except for the node defined in the group ucp_main.

• playbooks/create_main_dtr.yml installs and configures the first Docker DTR instance on the target node defined by the group dtr_main in the vm_hosts inventory.

• playbooks/config_scheduler.yml configures the scheduler to prevent regular users (i.e. non-admin users) scheduling containers on the Docker nodes running instances of UCP and DTR.

• playbooks/scale_dtr.yml installs and configures additional instances (or replicas) of DTR on the target nodes defined by the group dtr in the vm_hosts inventory, with the exception of the node defined in the group dtr_main.

• playbooks/reconfigure_dtr.yml is used to reconfigure DTR with the FQDN of the UCP Load Balancer and also enables image scanning.