ceph-ansible/infrastructure-playbooks/take-over-existing-cluster.yml

---
# NOTE (leseb):
# The playbook aims to takeover a cluster that was not configured with
# ceph-ansible.
#
# The procedure is as follows:
#
# 1. Install Ansible and add your monitors and osds hosts in it. For more detailed information you can read the [Ceph Ansible Wiki](https://github.com/ceph/ceph-ansible/wiki)
# 2. Set  `generate_fsid: false` in `group_vars`
# 3. Get your current cluster fsid with `ceph fsid` and set `fsid` accordingly in `group_vars`
# 4. Run the playbook called: `take-over-existing-cluster.yml` like this `ansible-playbook take-over-existing-cluster.yml`.
# 5. Eventually run Ceph Ansible to validate everything by doing: `ansible-playbook site.yml`.

- name: Fetch keys
  hosts: mons
  become: true
  tasks:
    - name: Import ceph-defaults role
      ansible.builtin.import_role:
        name: ceph-defaults

    - name: Import ceph-fetch-keys role
      ansible.builtin.import_role:
        name: ceph-fetch-keys

- name: Take over existing cluster
  hosts:
    - mons
    - osds
    - mdss
    - rgws
    - nfss
    - rbdmirrors
    - clients
    - mgrs
  become: true
  tasks:
    - name: Import ceph-defaults role
      ansible.builtin.import_role:
        name: ceph-defaults

  post_tasks:
    - name: Get the name of the existing ceph cluster
      ansible.builtin.shell: |
          set -o pipefail;
          basename $(grep --exclude '*.bak' -R fsid /etc/ceph/ | egrep -o '^[^.]*' | head -n 1)
      changed_when: false
      register: cluster_name

    - name: Run stat module on Ceph configuration file
      ansible.builtin.stat:
        path: "/etc/ceph/{{ cluster_name.stdout }}.conf"
      register: ceph_conf_stat

      # Creates a backup of original ceph conf file in 'cluster_name-YYYYMMDDTHHMMSS.conf.bak' format
    - name: Make a backup of original Ceph configuration file
      ansible.builtin.copy:
        src: "/etc/ceph/{{ cluster_name.stdout }}.conf"
        dest: "/etc/ceph/{{ cluster_name.stdout }}-{{ ansible_date_time.iso8601_basic_short }}.conf.bak"
        remote_src: true
        owner: "{{ ceph_conf_stat.stat.pw_name }}"
        group: "{{ ceph_conf_stat.stat.gr_name }}"
        mode: "{{ ceph_conf_stat.stat.mode }}"

    - name: Generate ceph configuration file
      openstack.config_template.config_template:
        src: "roles/ceph-config/templates/ceph.conf.j2"
        dest: "/etc/ceph/{{ cluster_name.stdout }}.conf"
        owner: "{{ ceph_conf_stat.stat.pw_name }}"
        group: "{{ ceph_conf_stat.stat.gr_name }}"
        mode: "{{ ceph_conf_stat.stat.mode }}"
        config_overrides: "{{ ceph_conf_overrides }}"
        config_type: ini