# Hooks The ansible installer allows for operators to execute custom tasks during specific operations through a system called hooks. Hooks allow operators to provide files defining tasks to execute before and/or after specific areas during installations and upgrades. This can be very helpful to validate or modify custom infrastructure when installing/upgrading OpenShift. It is important to remember that when a hook fails the operation fails. This means a good hook can run multiple times and provide the same results. A great hook is idempotent. **Note**: There is currently not a standard interface for hooks. In the future a standard interface will be defined and any hooks that existed previously will need to be updated to meet the new standard. ## Using Hooks Hooks are defined in the ``hosts`` inventory file under the ``OSEv3:vars`` section. Each hook should point to a yaml file which defines Ansible tasks. This file will be used as an include meaning that the file can not be a playbook but a set of tasks. Best practice suggests using absolute paths to the hook file to avoid any ambiguity. ### Example ```ini [OSEv3:vars] # openshift_master_upgrade_pre_hook=/usr/share/custom/pre_master.yml openshift_master_upgrade_hook=/usr/share/custom/master.yml openshift_master_upgrade_post_hook=/usr/share/custom/post_master.yml # ``` Hook files must be a yaml formatted file that defines a set of Ansible tasks. The file may **not** be a playbook. ### Example ```yaml --- # Trivial example forcing an operator to ack the start of an upgrade # file=/usr/share/custom/pre_master.yml - name: note the start of a master upgrade debug: msg: "Master upgrade of {{ inventory_hostname }} is about to start" - name: require an operator agree to start an upgrade pause: prompt: "Hit enter to start the master upgrade" ``` ## Upgrade Hooks ### openshift_master_upgrade_pre_hook - Runs **before** each master is upgraded. - This hook runs against **each master** in serial. - If a task needs to run against a different host, said task will need to use [``delegate_to`` or ``local_action``](http://docs.ansible.com/ansible/playbooks_delegation.html#delegation). ### openshift_master_upgrade_hook - Runs **after** each master is upgraded but **before** it's service/system restart. - This hook runs against **each master** in serial. - If a task needs to run against a different host, said task will need to use [``delegate_to`` or ``local_action``](http://docs.ansible.com/ansible/playbooks_delegation.html#delegation). ### openshift_master_upgrade_post_hook - Runs **after** each master is upgraded and has had it's service/system restart. - This hook runs against **each master** in serial. - If a task needs to run against a different host, said task will need to use [``delegate_to`` or ``local_action``](http://docs.ansible.com/ansible/playbooks_delegation.html#delegation).