OpenShift-Ansible Installer Checkpoint ====================================== A complete OpenShift cluster installation is comprised of many different components which can take 30 minutes to several hours to complete. If the installation should fail, it could be confusing to understand at which component the failure occurred. Additionally, it may be desired to re-run only the component which failed instead of starting over from the beginning. Components which came after the failed component would also need to be run individually. Design ------ The Installer Checkpoint implements an Ansible callback plugin to allow displaying and logging of the installer status at the end of a playbook run. To ensure the callback plugin is loaded, regardless of ansible.cfg file configuration, the plugin has been placed inside the installer_checkpoint role which must be called early in playbook execution. The `init/main.yml` playbook is run first for all entry point playbooks, therefore, the initialization of the checkpoint plugin has been placed at the beginning of that file. Playbooks use the [set_stats][set_stats] Ansible module to set a custom stats variable indicating the status of the phase being executed. The installer_checkpoint.py callback plugin extends the Ansible `v2_playbook_on_stats` method, which is called at the end of a playbook run, to display the status of each phase which was run. The INSTALLER STATUS report is displayed immediately following the PLAY RECAP. Phases of cluster installation are mapped to the steps in the [common/openshift-cluster/config.yml][openshift_cluster_config] playbook. To correctly display the order of the installer phases, the `installer_phases` variable defines the phase or component order. ```python # Set the order of the installer phases installer_phases = [ 'installer_phase_initialize', 'installer_phase_etcd', 'installer_phase_nfs', 'installer_phase_loadbalancer', 'installer_phase_master', 'installer_phase_master_additional', 'installer_phase_node', 'installer_phase_glusterfs', 'installer_phase_hosted', 'installer_phase_metrics', 'installer_phase_logging', 'installer_phase_servicecatalog', ] ``` Additional attributes, such as display title and component playbook, of each phase are stored in the `phase_attributes` variable. ```python # Define the attributes of the installer phases phase_attributes = { 'installer_phase_initialize': { 'title': 'Initialization', 'playbook': '' }, 'installer_phase_etcd': { 'title': 'etcd Install', 'playbook': 'playbooks/openshift-etcd/config.yml' }, 'installer_phase_nfs': { 'title': 'NFS Install', 'playbook': 'playbooks/openshift-nfs/config.yml' }, #... } ``` Usage ----- In order to indicate the beginning of a component installation, a play must be added to the beginning of the main playbook for the component to set the phase status to "In Progress". Additionally, a play must be added after the last play for that component to set the phase status to "Complete". The following example shows the first play of the 'installer phase' loading the `installer_checkpoint` role, as well as the `set_stats` task for setting `installer_phase_initialize` to "In Progress". Various plays are run for the phase/component and then a final play for setting `installer_hase_initialize` to "Complete". ```yaml # init/main.yml --- - name: Initialization Checkpoint Start hosts: all gather_facts: false roles: - installer_checkpoint tasks: - name: Set install initialization 'In Progress' run_once: true set_stats: data: installer_phase_initialize: status: "In Progress" start: "{{ lookup('pipe', 'date +%Y%m%d%H%M%SZ') }}" #... # Various plays here #... - name: Initialization Checkpoint End hosts: all gather_facts: false tasks: - name: Set install initialization 'Complete' run_once: true set_stats: data: installer_phase_initialize: status: "Complete" end: "{{ lookup('pipe', 'date +%Y%m%d%H%M%SZ') }}" ``` Each phase or component of the installer will follow a similar pattern, with the exception that the `installer_checkpoint` role does not need to be called since it was already loaded by the play in `init/main.yml`. It is important to place the 'In Progress' and 'Complete' plays as the first and last plays of the phase or component. Examples -------- Example display of a successful playbook run: ``` PLAY RECAP ********************************************************************* master01.example.com : ok=158 changed=16 unreachable=0 failed=0 node01.example.com : ok=469 changed=74 unreachable=0 failed=0 node02.example.com : ok=157 changed=17 unreachable=0 failed=0 localhost : ok=24 changed=0 unreachable=0 failed=0 INSTALLER STATUS *************************************************************** Initialization : Complete (0:02:14) Health Check : Complete (0:01:10) etcd Install : Complete (0:02:01) Master Install : Complete (0:11:43) Master Additional Install : Complete (0:00:54) Node Install : Complete (0:14:11) Hosted Install : Complete (0:03:28) ``` Example display if a failure occurs during execution: ``` INSTALLER STATUS *************************************************************** Initialization : Complete (0:02:14) Health Check : Complete (0:01:10) etcd Install : Complete (0:02:58) Master Install : Complete (0:09:20) Master Additional Install : In Progress (0:20:04) This phase can be restarted by running: playbooks/openshift-master/additional_config.yml ``` [set_stats]: http://docs.ansible.com/ansible/latest/set_stats_module.html [openshift_cluster_config]: https://github.com/openshift/openshift-ansible/blob/master/playbooks/common/openshift-cluster/config.yml