Chapter 19. Installing an Identity Management replica using an Ansible playbook

19.1. Ansible and its advantages for installing IdM

Ansible is an automation tool used to configure systems, deploy software, and perform rolling updates. Ansible includes support for Identity Management (IdM), and you can use Ansible modules to automate installation tasks such as the setup of an IdM server, replica, client, or an entire IdM topology.

Advantages of using Ansible to install IdM

The following list presents advantages of installing Identity Management using Ansible in contrast to manual installation.

  • You do not need to log into the managed node.
  • You do not need to configure settings on each host to be deployed individually. Instead, you can have one inventory file to deploy a complete cluster.
  • You can reuse an inventory file later for management tasks, for example to add users and hosts. You can reuse an inventory file even for such tasks as are not related to IdM.

19.2. IdM replica installation using an Ansible playbook

The following sections describe how to configure a system as an IdM replica by using Ansible. Configuring a system as an IdM replica enrolls it into an IdM domain and enables the system to use IdM services on IdM servers in the domain.

The deployment is managed by the ipareplica Ansible role. The role can use the autodiscovery mode for identifying the IdM servers, domain and other settings. However, if you deploy multiple replicas in a tier-like model, with different groups of replicas being deployed at different times, you must defined specific servers or replicas for each group.

Note

Before installing an IdM replica using Ansible, ensure that you understand Ansible and IdM concepts. Ensure that you understand the following terms that are used in this chapter:

  • Ansible roles
  • Ansible nodes
  • Ansible inventory
  • Ansible tasks
  • Ansible modules
  • Ansible plays and playbooks

Overview

The installation consists of the following parts:

  1. Installing the ansible-freeipa package;

  2. Setting the parameters of the IdM replica deployment, namely:

  3. Deploying an IdM replica using an Ansible playbook.

19.3. Installing the ansible-freeipa package

Prerequisites

On the managed node:

  • Ensure that the managed node is a Red Hat Enterprise Linux 8 system with a static IP address and a working package manager.

On the controller:

  • Ensure that the controller is a Red Hat Enterprise Linux system with a valid subscription. If this is not the case, see the official Ansible documentation Installation guide for alternative installation instructions.
  • Ensure that you can reach the managed node over the SSH protocol from the controller. Check that the managed node is listed in the /root/.ssh/known_hosts file of the controller.

Procedure

Run the following procedure on the Ansible controller.

  1. Enable the required repository: 

    # subscription-manager repos --enable ansible-2.8-for-rhel-8-x86_64-rpms

  2. Install Ansible: 

    # yum install ansible

  3. Install the IdM Ansible roles: 

    # yum install ansible-freeipa

    The roles are installed to the /usr/share/ansible/roles/ directory.

19.4. Ansible roles location in the file system

By default the ansible-freeipa roles are installed to the /usr/share/ansible/roles/ directory. The structure of the ansible-freeipa package is as follows:

  • The /usr/share/ansible/roles/ directory stores the ipaserver, ipareplica, and ipaclient roles on the Ansible controller. Each role directory stores examples, a basic overview, the licence and documentation about the role in a README.md Markdown file. 

    [root@server]# ls -1 /usr/share/ansible/roles/
ipaclient
ipareplica
ipaserver

  • The /usr/share/doc/ansible-freeipa/ directory stores the documentation about individual roles and the topology in README.md Markdown files. It also stores the playbooks/ subdirectory (see below). 

    [root@server]# ls -1 /usr/share/doc/ansible-freeipa/
playbooks
README-client.md
README.md
README-replica.md
README-server.md
README-topology.md

  • The /usr/share/doc/ansible-freeipa/playbooks/ directory stores the example playbooks: 

    [root@server]# ls -1 /usr/share/doc/ansible-freeipa/playbooks/
install-client.yml
install-cluster.yml
install-replica.yml
install-server.yml
uninstall-client.yml
uninstall-cluster.yml
uninstall-replica.yml
uninstall-server.yml

19.5. Setting the parameters of the IdM replica deployment

Before you deploy a target host as an IdM replica, configure the following settings:

19.5.1. Specifying the base, server and client variables for installing the IdM replica

Complete this procedure to configure the inventory file for installing an IdM replica.

Procedure

  1. Open the inventory file for editing. Specify the fully-qualified domain names (FQDN) of the hosts to become IdM replicas. The FQDNs must be valid DNS names:

    • Only numbers, alphabetic characters, and hyphens (-) are allowed. For example, underscores are not allowed and can cause DNS failures.

    • The host name must be all lower-case.

      Example of a simple inventory hosts file with only the replicas' FQDN defined

      [ipareplicas]
replica1.idm.example.com
replica2.idm.example.com
replica3.idm.example.com
[...]

      If the IdM master server is already deployed and the SRV records are set properly in the IdM DNS zone, the script automatically discovers all the other required values.

  2. Optionally, provide additional information in the inventory file based on which of the following scenarios is closest to yours:

    • Scenario 1

      If you want to avoid autodiscovery and have all replicas listed in the [ipareplicas] section use a specific IdM server, set the server in the [ipaservers] section of the inventory file.

      Example inventory hosts file with the FQDN of the IdM server and replicas defined

      [ipaservers]
server.idm.example.com

[ipareplicas]
replica1.idm.example.com
replica2.idm.example.com
replica3.idm.example.com
[...]

    • Scenario 2

      Alternatively, if you want to avoid autodiscovery but want to deploy specific replicas with specific servers, set the servers for specific replicas individually in the [ipareplicas] section in the inventory file.

      Example inventory file with a specific IdM server defined for a specific replica

      [ipaservers]
server.idm.example.com
replica1.idm.example.com

[ipareplicas]
replica2.idm.example.com
replica3.idm.example.com ipareplica_servers=replica1.idm.example.com

      In the example above, replica3.idm.example.com uses the already deployed replica1.idm.example.com as its master server.

    • Scenario 3

      If you are deploying several replicas in one batch and time is a concern to you, multitier replica deployment can be useful for you. Define specific groups of replicas in the inventory file, for example [ipareplicas_tier1] and [ipareplicas_tier2], and design separate plays for each group in the install-replica.yml playbook.

      Example inventory file with replica tiers defined

      [ipaservers]
server.idm.example.com

[ipareplicas_tier1]
replica1.idm.example.com

[ipareplicas_tier2]
replica2.idm.example.com \ ipareplica_servers=replica1.idm.example.com,server.idm.example.com

      The first entry in ipareplica_servers will be used as the master. The second entry will be used as a fallback option. When using multiple tiers for deploying IdM replicas, you must have separate tasks in the playbook to first deploy replicas from tier1 and then replicas from tier2:

      Example of a playbook file with different plays for different replica groups

      ---
- name: Playbook to configure IPA replicas (tier1)
  hosts: ipareplicas_tier1
  become: true

  roles:
  - role: ipareplica
    state: present

- name: Playbook to configure IPA replicas (tier2)
  hosts: ipareplicas_tier2
  become: true

  roles:
  - role: ipareplica
    state: present

19.5.2. Specifying the credentials for installing the IdM replica using an Ansible playbook

Complete this procedure to configure the authorization for installing the IdM replica.

Procedure

  1. Specify the password of a user authorized to deploy replicas, for example the IdM admin.

    • Red Hat recommends using the Ansible Vault to store the password, and referencing the Vault file from the playbook file, for example install-replica.yml:

      Example playbook file using principal from inventory file and password from an Ansible Vault file

      - name: Playbook to configure IPA replicas
  hosts: ipareplicas
  become: true
  vars_files:
  - playbook_sensitive_data.yml

  roles:
  - role: ipareplica
    state: present

      For details how to use Ansible Vault, see the official Ansible Vault documentation.

    • Less securely, provide the credentials of admin directly in the inventory file. Use the ipaadmin_password option in the [ipareplicas:vars] section of the inventory file. The inventory file and the install-replica.yml playbook file can then look as follows:

      Example inventory hosts.replica file

      [...]
[ipareplicas:vars]
ipaadmin_password=Secret123

      Example playbook using principal and password from inventory file

      - name: Playbook to configure IPA replicas
  hosts: ipareplicas
  become: true

  roles:
  - role: ipareplica
    state: present

    • Alternatively but also less securely, provide the credentials of another user authorized to deploy a replica directly in the inventory file. To specify a different authorized user, use the ipaadmin_principal option for the user name, and the ipaadmin_password option for the password. The inventory file and the install-replica.yml playbook file can then look as follows:

      Example inventory hosts.replica file

      [...]
[ipareplicas:vars]
ipaadmin_principal=my_admin
ipaadmin_password=my_admin_secret123

      Example playbook using principal and password from inventory file

      - name: Playbook to configure IPA replicas
  hosts: ipareplicas
  become: true

  roles:
  - role: ipareplica
    state: present

Additional resources

  • For details on the options accepted by the ipareplica Ansible role, see the /usr/share/ansible/roles/ipareplica/README.md Markdown file.

19.6. Deploying an IdM replica using an Ansible playbook

Complete this procedure to use an Ansible playbook to deploy an IdM replica.

Procedure

  • To install an IdM replica using an Ansible playbook, use the ansible-playbook command with the name of the playbook file, for example install-replica.yml. Specify the inventory file with the -i option: 

    $ ansible-playbook -v -i <path_to_inventory_directory>/hosts.replica <path_to_playbooks_directory>/install-replica.yml

    Specify the level of verbosity by using the -v, -vv or -vvv option.

    Ansible informs you about the execution of the Ansible playbook script. The following output shows that the script has run successfully as 0 tasks have failed: 

    PLAY RECAP
replica.idm.example.com : ok=18   changed=10   unreachable=0    failed=0    skipped=21   rescued=0    ignored=0

You have now installed an IdM replica.