Ansible templates

You may run Ansible on the same instance or anywhere else from where you can connect to your instance via SSH, such as another instance in the same private network, or from your own computer if your instance can be reached over SSH. We will refer to this as your seed platform. You will need at least git and python available to follow these steps.

1. On your seed platform, clone the repository and cd into the directory:
   

   git clone <repository-url> cd <repository>

2. If you don't have Ansible installed, you may install it with pip:
   

   pip install --user -r requirements.txt

   or if you prefer to do it in a virtual environment:
   

   python3 -m venv ansible-venv source ansible-venv/bin/activate pip install -r requirements.txt

3. Install the necessary Ansible roles that are going to be used by the playbooks:
   

   ansible-galaxy role install -r requirements.yml roles/

4. If you don't have it already, define your Ansible inventory. The simplest approach would be to create a file called inventory, on the same directory where the plabooks are, containing the fully qualified domain name (FQDN) or IP address used to connect to the instance from your seed platform. If running on the same instance, you may use localhost.
5. Apply the desired playbook with ansible-playbook:
   

   ansible-playbook -i inventory playbookname.yml

   You may pass additional options to ansible-playbook, such as:
   • -v for verbose output
   • -K for asking sudo password, if your user does not have password-less sudo privileges on the target instance.
   • -u yourremoteuser if Ansible needs to use a specific user account to connect to the target instance.
   • -e var=value for add-hoc customisation of playbook variables to customise your installation.

For advanced users with existing Ansible playbooks and greater customisation needs, it is possible to just pick and choose roles you are interested and include them into your own playbooks, instead of running separate playbooks. You can find the URLs for each of the dependant roles in the requirements.yml file. 

1. Open your playbook file and include the roles that you are interested in. For example, here is a playbook that includes 3 roles and customises some variable:
   

   --- - hosts: all   become: yes   vars:     conda_prefix: /opt/conda   tasks:     - name: Mars client       ansible.builtin.include_role:         name: ewc-ansible-role-mars-client       - name: ML basic stack       ansible.builtin.include_role:         name: ewc-ansible-role-ml-basic       - name: Anemoi       ansible.builtin.include_role:         name: ewc-ansible-role-ecmwf-anemoi

   
   See the official Ansible documentation for more information on roles and how to include them. 
2. Make sure the necessary roles are available before you run the playbook. For that you may install them with ansible-galaxy either individually or writing your own requirements.yml. For the example above, this could be a requirements.yaml file:
   

   --- # Ansible Requirements roles: - name: ewc-ansible-role-mars-client src: https://github.com/ewcloud/ewc-ansible-role-mars-client.git version: main - name: ewc-ansible-role-conda src: https://github.com/ewcloud/ewc-ansible-role-conda.git version: main - name: ewc-ansible-role-ml-basic src: https://github.com/ewcloud/ewc-ansible-role-ml-basic.git version: main - name: ewc-ansible-role-anemoi src: https://github.com/ewcloud/ewc-ansible-role-anemoi.git version: main

   
   See the official Ansible documentation for more details on how to create such file.
3. Install the roles with ansible-galaxy:
   

   ansible-galaxy role install -r requirements.yml roles/

4. Run the playbook

   $ ansible-playbook -i inventory myplaybook.yml