Installing the Undercloud

  1. Log in to your machine (baremetal or VM) where you want to install the undercloud as a non-root user (such as the stack user):

    ssh <non-root-user>@<undercloud-machine>


    If you don’t have a non-root user created yet, log in as root and create one with following commands:

    sudo useradd stack
    sudo passwd stack  # specify a password
    echo "stack ALL=(root) NOPASSWD:ALL" | sudo tee -a /etc/sudoers.d/stack
    sudo chmod 0440 /etc/sudoers.d/stack
    su - stack


    The undercloud is intended to work correctly with SELinux enforcing, and cannot be installed to a system with SELinux disabled. If SELinux enforcement must be turned off for some reason, it should instead be set to permissive.


    vlan tagged interfaces must follow the if_name.vlan_id convention, like for example: eth0.vlan100 or bond0.vlan120.


    Ensure that there is a FQDN hostname set and that the $HOSTNAME environment variable matches that value. The easiest way to do this is to set the undercloud_hostname option in undercloud.conf before running the install. This will allow the installer to configure all of the hostname- related settings appropriately.

    Alternatively the hostname settings can be configured manually, but this is strongly discouraged. The manual steps are as follows:

    sudo hostnamectl set-hostname myhost.mydomain
    sudo hostnamectl set-hostname --transient myhost.mydomain

    An entry for the system’s FQDN hostname is also needed in /etc/hosts. For example, if the system is named myhost.mydomain, /etc/hosts should have an entry like:   myhost.mydomain myhost
  2. Enable needed repositories:


    Enable optional repo:

    sudo yum install -y yum-utils
    sudo yum-config-manager --enable rhelosp-rhel-7-server-opt

    Download and install the python2-tripleo-repos RPM from the current RDO repository. For example

    sudo yum install -y<version>.el7.centos.noarch.rpm


    tripleo-repos removes any repositories that it manages before each run. This means all repositories must be specified in a single tripleo-repos call. As an example, the correct way to install the current and ceph repos is to run tripleo-repos current ceph, not two separate calls.

    Stable Branch

    Enable the appropriate repos for the desired release, as indicated below. Do not enable any other repos not explicitly marked for that release.


    Enable the current Newton repositories

    sudo -E tripleo-repos -b newton current


    Include the Ceph repo in the tripleo-repos call

    sudo -E tripleo-repos -b newton current ceph


    Enable the current Ocata repositories

    sudo -E tripleo-repos -b ocata current


    Include the Ceph repo in the tripleo-repos call

    sudo -E tripleo-repos -b ocata current ceph


    Enable the current Pike repositories

    sudo -E tripleo-repos -b pike current


    Include the Ceph repo in the tripleo-repos call

    sudo -E tripleo-repos -b pike current ceph


    Enable the current Queens repositories

    sudo -E tripleo-repos -b queens current


    Include the Ceph repo in the tripleo-repos call

    sudo -E tripleo-repos -b queens current ceph


    The remaining repositories configuration steps below should not be done for stable releases!

    Run tripleo-repos to install the appropriate repositories. The option below will enable the latest master TripleO packages and the latest promoted packages for all other OpenStack services and dependencies. There are other repository configurations available in tripleo-repos, see its –help output for details.

    sudo -E tripleo-repos current-tripleo-dev


    Include the Ceph repository in the tripleo-repos command

    sudo -E tripleo-repos current-tripleo-dev ceph
  1. Install the TripleO CLI, which will pull in all other necessary packages as dependencies:

    sudo yum install -y python-tripleoclient


    If you intend to deploy Ceph in the overcloud, or configure the overcloud to use an external Ceph cluster, and are running Pike or newer, then install ceph-ansible on the undercloud:

    sudo yum install -y ceph-ansible
  2. For a non-containerized undercloud, copy in the sample configuration file and edit it to reflect your environment:

    cp /usr/share/instack-undercloud/undercloud.conf.sample ~/undercloud.conf


    There is a tool available that can help with writing a basic undercloud.conf: Undercloud Configuration Wizard It takes some basic information about the intended overcloud environment and generates sane values for a number of the important options.

  3. For a containerized undercloud, use this file:

    cp /usr/share/python-tripleoclient/undercloud.conf.sample ~/undercloud.conf
  4. Run the command to install the undercloud:


    To deploy an undercloud with SSL, see Deploying with SSL.


    Validations will be installed and configured during undercloud installation. You can set enable_validations = false in undercloud.conf to prevent that.

    Stable Branch

    The containerized undercloud deployment isn’t supported before Rocky release.

    Install the undercloud:

    openstack undercloud install

    To deploy a containerized undercloud, just add –use-heat option:

    openstack undercloud install --use-heat


When installing a containerized undercloud, it’s possible to enable verbose logging with –verbose option.


The openstack undercloud install –use-heat command will run all the OpenStack services in a container runtime (docker) unless the default settings are overwritten. This command requires 2 services to be running at all times. The first one is a basic keystone service, which is currently executed by tripleoclient itself, the second one is heat-all which executes the templates and installs the services. The latter can be run on baremetal or in a container (tripleoclient will run it in a container by default).

Once the install has completed, you should take note of the files stackrc and undercloud-passwords.conf. You can source stackrc to interact with the undercloud via the OpenStack command-line client. undercloud-passwords.conf contains the passwords used for each service in the undercloud. These passwords will be automatically reused if the undercloud is reinstalled on the same system, so it is not necessary to copy them to undercloud.conf.


Any passwords set in undercloud.conf will take precedence over the ones in undercloud-passwords.conf.


openstack undercloud install can be rerun to reapply changes from undercloud.conf to the undercloud. Note that this should not be done if an overcloud has already been deployed or is in progress.


If running docker commands as a stack user after an undercloud install fail with a permission error, log out and log in again. The stack user does get added to the docker group during install, but that change gets reflected only after a new login.