D7.5 Backup & Restore Volumes με Ansible 🔄

Η στρατηγική backup

Τα Docker volumes περιέχουν τα πιο κρίσιμα δεδομένα της υποδομής σου (databases, uploads, config). Η Ansible δίνει ένα ισχυρό, idempotent pattern για backup και restore.

Backup Strategy:
│
├── Consistency:
│   └── Σταμάτα container → backup → ξεκίνα ξανά
│       (ή: flush tables σε MySQL/PostgreSQL)
│
├── Storage:
│   ├── Τοπικό (στον ίδιο host)
│   ├── Remote (rsync σε backup server)
│   └── Object storage (S3, MinIO)
│
└── Retention:
    └── Κράτα Ν ημέρες, διέγραψε παλιά
  

Pattern 1: Tar backup με helper container

Ο πιο portable τρόπος — χρησιμοποιεί έναν temporary container:

tasks:

  # ── Δημιουργία backup directory ────────────
  - name: Backup directory
    ansible.builtin.file:
      path:  "/opt/backups/docker/{{ inventory_hostname }}"
      state: directory
      mode:  '0750'

  # ── Backup named volume με temp container ──
  - name: "Backup volume: {{ volume_name }}"
    community.docker.docker_container:
      name:           backup_tmp
      image:          alpine:latest
      state:          started
      auto_remove:    true        # ← αυτόματη διαγραφή
      detach:         false       # ← περιμένει να τελειώσει
      command: >
        tar czf /backup/{{ volume_name }}-{{ ansible_date_time.date }}.tar.gz
        -C /data .
      volumes:
        - "{{ volume_name }}:/data:ro"           # ← το volume
        - "/opt/backups/docker/{{ inventory_hostname }}:/backup:rw"
      # ↑ ro: δεν αλλάζουμε τίποτα στο volume!

  - name: Επαλήθευση backup
    ansible.builtin.stat:
      path: "/opt/backups/docker/{{ inventory_hostname }}/{{ volume_name }}-{{ ansible_date_time.date }}.tar.gz"
    register: backup_file

  - name: Αποτέλεσμα backup
    ansible.builtin.debug:
      msg: >
        {{ volume_name }}:
        {{ '✅ ' + (backup_file.stat.size | human_readable) if backup_file.stat.exists
                else '❌ Backup απέτυχε!' }}
  

Pattern 2: Database-aware backup (PostgreSQL)

Για databases, χρειάζεσαι consistent backup — όχι απλό tar:

tasks:

  # ── PostgreSQL dump ──────────────────────
  - name: PostgreSQL backup
    community.docker.docker_container:
      name:        pg_backup_tmp
      image:       postgres:15-alpine
      state:       started
      auto_remove: true
      detach:      false
      command: >
        pg_dumpall
        -h postgres_db
        -U {{ postgres_user }}
        -f /backup/postgres-{{ ansible_date_time.date }}.sql
      volumes:
        - "/opt/backups/docker/{{ inventory_hostname }}:/backup:rw"
      networks:
        - name: backend_net    # ← ίδιο network με τον postgres!
      env:
        PGPASSWORD: "{{ vault_postgres_pass }}"
      no_log: true

  # ── Συμπίεση dump ─────────────────────────
  - name: Συμπίεση SQL dump
    ansible.builtin.command:
      cmd: >
        gzip -f
        /opt/backups/docker/{{ inventory_hostname }}/postgres-{{ ansible_date_time.date }}.sql
    changed_when: true

  # ── MySQL dump ────────────────────────────
  - name: MySQL backup
    community.docker.docker_container:
      name:        mysql_backup_tmp
      image:       mysql:8.0
      state:       started
      auto_remove: true
      detach:      false
      command: >
        mysqldump
        -h mysql_db
        -u {{ mysql_user }}
        --all-databases
        --single-transaction
        --quick
        --lock-tables=false
      volumes:
        - "/opt/backups/docker/{{ inventory_hostname }}:/backup:rw"
      networks:
        - name: backend_net
      env:
        MYSQL_PWD: "{{ vault_mysql_pass }}"
      no_log: true
    register: mysql_dump

  - name: Αποθήκευση MySQL dump
    ansible.builtin.copy:
      content: "{{ mysql_dump.Output }}"
      dest:    "/opt/backups/docker/{{ inventory_hostname }}/mysql-{{ ansible_date_time.date }}.sql"
      mode:    '0640'
    when: not mysql_dump.failed
  

Pattern 3: Restore από backup

tasks:

  # ── Restore named volume ─────────────────
  - name: "⚠️ Restore volume: {{ volume_name }}"
    block:

      # ── Σταμάτα containers ──────────────
      - name: Σταμάτα dependent containers
        community.docker.docker_container:
          name:  "{{ item }}"
          state: stopped
        loop: "{{ containers_using_volume }}"
        ignore_errors: true

      # ── Restore ────────────────────────
      - name: Restore volume από backup
        community.docker.docker_container:
          name:        restore_tmp
          image:       alpine:latest
          state:       started
          auto_remove: true
          detach:      false
          command: >
            sh -c "rm -rf /data/* &&
                   tar xzf /backup/{{ backup_file_name }}
                   -C /data ."
          volumes:
            - "{{ volume_name }}:/data:rw"           # ← εγγραφή!
            - "/opt/backups/docker/{{ inventory_hostname }}:/backup:ro"

      # ── Ξεκίνα containers ─────────────
      - name: Ξεκίνα containers
        community.docker.docker_container:
          name:  "{{ item }}"
          state: started
        loop: "{{ containers_using_volume }}"

    rescue:

      - name: "❌ Restore απέτυχε!"
        ansible.builtin.debug:
          msg: "Ελέγξτε το backup αρχείο: {{ backup_file_name }}"

  # ── PostgreSQL restore ────────────────────
  - name: PostgreSQL restore
    community.docker.docker_container:
      name:        pg_restore_tmp
      image:       postgres:15-alpine
      state:       started
      auto_remove: true
      detach:      false
      command: >
        psql
        -h postgres_db
        -U {{ postgres_user }}
        -f /backup/{{ backup_file_name }}
      volumes:
        - "/opt/backups/docker/{{ inventory_hostname }}:/backup:ro"
      networks:
        - name: backend_net
      env:
        PGPASSWORD: "{{ vault_postgres_pass }}"
      no_log: true
  

Retention — Διατήρηση για N ημέρες

tasks:

  - name: Αφαίρεση παλιών backups (> {{ retention_days }} ημέρες)
    ansible.builtin.find:
      paths:   "/opt/backups/docker/{{ inventory_hostname }}"
      patterns: "*.tar.gz,*.sql.gz"
      age:     "{{ retention_days }}d"
      age_stamp: mtime
    register: old_backups

  - name: Διαγραφή παλιών backups
    ansible.builtin.file:
      path:  "{{ item.path }}"
      state: absent
    loop: "{{ old_backups.files }}"
    loop_control:
      label: "{{ item.path | basename }}"
    when: old_backups.files | length > 0

  - name: Αναφορά retention
    ansible.builtin.debug:
      msg: >
        Διαγράφηκαν {{ old_backups.files | length }}
        αρχεία παλιότερα από {{ retention_days }} ημέρες.
  

Πλήρες Backup Playbook

---
# docker-volume-backup.yml

- name: Docker Volume Backup
  hosts: "{{ target | default('all_managed') }}"
  become: true
  gather_facts: true

  vars:
    backup_base:    /opt/backups/docker
    retention_days: 7
    backup_date:    "{{ ansible_date_time.date }}"

    volumes_to_backup:
      - name:      postgres_data
        type:      postgres
        container: postgres_db
        network:   backend_net
        db_user:   "{{ postgres_user }}"
        db_pass:   "{{ vault_postgres_pass }}"
      - name:      app_uploads
        type:      generic
        container: myapp
      - name:      redis_data
        type:      generic
        container: redis

  tasks:

    # ── Προετοιμασία ──────────────────────────
    - name: Backup directory
      ansible.builtin.file:
        path:  "{{ backup_base }}/{{ inventory_hostname }}"
        state: directory
        mode:  '0750'

    # ── Backup loop ───────────────────────────
    - name: "💾 Backup: {{ item.name }}"
      block:

        # Generic tar backup
        - name: "Tar backup: {{ item.name }}"
          community.docker.docker_container:
            name:        "backup_{{ item.name }}_tmp"
            image:       alpine:latest
            state:       started
            auto_remove: true
            detach:      false
            command: >
              tar czf /backup/{{ item.name }}-{{ backup_date }}.tar.gz
              -C /data .
            volumes:
              - "{{ item.name }}:/data:ro"
              - "{{ backup_base }}/{{ inventory_hostname }}:/backup:rw"
          when: item.type == 'generic'

        # PostgreSQL dump
        - name: "PostgreSQL dump: {{ item.name }}"
          community.docker.docker_container:
            name:        "pgdump_{{ item.name }}_tmp"
            image:       postgres:15-alpine
            state:       started
            auto_remove: true
            detach:      false
            command: >
              bash -c "pg_dumpall -h {{ item.container }} -U {{ item.db_user }}
              | gzip > /backup/{{ item.name }}-{{ backup_date }}.sql.gz"
            volumes:
              - "{{ backup_base }}/{{ inventory_hostname }}:/backup:rw"
            networks:
              - name: "{{ item.network }}"
            env:
              PGPASSWORD: "{{ item.db_pass }}"
            no_log: true
          when: item.type == 'postgres'

      rescue:

        - name: "❌ Backup απέτυχε: {{ item.name }}"
          ansible.builtin.debug:
            msg: "Αποτυχία backup για {{ item.name }} — συνεχίζω..."

      loop: "{{ volumes_to_backup }}"
      loop_control:
        label: "{{ item.name }}"

    # ── Retention cleanup ─────────────────────
    - name: "🧹 Αφαίρεση backups > {{ retention_days }} ημέρες"
      ansible.builtin.find:
        paths:     "{{ backup_base }}/{{ inventory_hostname }}"
        patterns:  "*.tar.gz,*.sql.gz"
        age:       "{{ retention_days }}d"
        age_stamp: mtime
      register: old_backups

    - name: Διαγραφή παλιών
      ansible.builtin.file:
        path:  "{{ item.path }}"
        state: absent
      loop: "{{ old_backups.files }}"
      loop_control:
        label: "{{ item.path | basename }}"

    # ── Report ────────────────────────────────
    - name: "📊 Backup Report"
      ansible.builtin.find:
        paths:    "{{ backup_base }}/{{ inventory_hostname }}"
        patterns: "*.tar.gz,*.sql.gz"
        age:      "1d"
        age_stamp: mtime
      register: today_backups

    - name: Εμφάνιση αποτελεσμάτων
      ansible.builtin.debug:
        msg:
          - "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
          - "  Backup Report — {{ inventory_hostname }}"
          - "  Ημερομηνία: {{ backup_date }}"
          - "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
          - "{% for f in today_backups.files %}\
             {{ f.path | basename }}: {{ f.size | human_readable }}\
             {% endfor %}"
          - "  Παλιά (διαγράφηκαν): {{ old_backups.files | length }}"
          - "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
  

# Εκτέλεση
ansible-playbook playbooks/docker-volume-backup.yml \
    --limit nextcloud -v

# Dry run
ansible-playbook playbooks/docker-volume-backup.yml \
    --limit nextcloud --check

# Override retention
ansible-playbook playbooks/docker-volume-backup.yml \
    --limit nextcloud \
    -e "retention_days=14"
  

Σύνοψη D7.5

Backup & Restore Volumes
│
├── Backup patterns:
│   ├── Generic (tar): alpine container + tar czf
│   └── Database-aware:
│       ├── PostgreSQL: pg_dumpall
│       └── MySQL: mysqldump --single-transaction
│
├── Κλειδί: auto_remove + detach: false
│   ├── auto_remove: true → cleanup αυτόματα
│   └── detach: false    → Ansible περιμένει αποτέλεσμα
│
├── Retention:
│   ├── find module → αρχεία > N ημέρες
│   └── file: state=absent → διαγραφή
│
└── Best practices:
    ✅ Backup σε :ro mount (ασφάλεια)
    ✅ Consistent DB backups (dump, όχι tar)
    ✅ Αυτόματο retention cleanup
    ✅ Verification μετά backup
    ❌ ΠΟΤΕ docker prune volumes χωρίς έλεγχο
  