📦 Contributor Guide: Mounting Disks Using fstab Using Ansible

The fstab role provides a declarative, idempotent, and state-aware way to manage filesystem mounts via /etc/fstab. Unlike traditional approaches that only append entries, this role ensures the system’s mount configuration matches your desired state exactly—adding new mounts and removing those no longer defined.

🔗 Source repository: 👉 https://github.com/t3knoid/ansible/tree/main/roles/fstab

Unlike autofs, which performs on-demand NFS automounting, this role uses static /etc/fstab entries, making it suitable for both NFS and local disk mounts.

✨ Key Features

• Declarative — Define desired mounts; the role enforces that state
• Idempotent — Safe to run repeatedly; only changes when needed
• State-aware removal — Removes only mounts previously managed by this role
• Mount verification — Confirms a mount is active before unmounting
• Supports multiple filesystem types — NFS, ext4, xfs, vfat, and more
• Persistent mounts — Ensures mounts survive reboots via /etc/fstab

🧰 Prerequisites

• Target system must be Linux-based (Debian/Ubuntu recommended)

• Install the required collection:

  ansible-galaxy collection install ansible.posix
  

⚙️ Variables

🔴 Required

fstab_mounts (list): Array of mount configurations. Each entry must include:

• device — Device path or NFS export

  • Local: /dev/sdb1, /dev/vdc1
  • NFS: 192.168.2.240:/volume1/Photos, nfs-server:/export/share

• mount_point — Local mount path (e.g., /data, /nfs/music)

📐 Optional

🧠 How It Works

The role maintains declarative state by tracking which mounts it manages.

🔁 Role Execution Flow

1. Initialize — Load defaults and prepare variables
2. Calculate changes — Compare defined mounts vs. previously managed ones

3. Remove old mounts

   • Check if mounted
   • Unmount
   • Remove /etc/fstab entry
   • Delete mount directory

4. Add/update mounts

   • Create mount directory
   • Add/update /etc/fstab entry
   • Mount the filesystem

🧠 State Tracking

The role uses the fact fstab_mounts_managed to ensure:

• Only mounts created by this role are removed
• Manually managed mounts remain untouched
• Behavior is consistent across runs

🚀 Usage Examples

🟢 Basic NFS Mounts

- hosts: media_servers
  become: true
  roles:
    - fstab
  vars:
    fstab_mounts:
      - device: "192.168.2.240:/volume1/Photos"
        mount_point: "/nfs/photos"
        fstype: "nfs"
        opts: "rw,relatime,hard,rsize=1048576,wsize=1048576,proto=tcp,timeo=600,retrans=2,sec=sys"
      - device: "192.168.2.250:/mnt/Data/music"
        mount_point: "/nfs/music"
        fstype: "nfs"
        opts: "rw,relatime,hard,rsize=1048576,wsize=1048576,proto=tcp,timeo=600,retrans=2,sec=sys"

🗃 Local Disk Mounts

fstab_mounts:
  - device: "/dev/sdb1"
    mount_point: "/data"
    fstype: "ext4"
    opts: "defaults,nofail"
  - device: "/dev/sdc1"
    mount_point: "/backup"
    fstype: "ext4"
    opts: "defaults,noatime"

🗂 Mixed Mount Types

fstab_mounts:
  - device: "/dev/sdb1"
    mount_point: "/local-storage"
    fstype: "ext4"
  - device: "nfs-server:/export"
    mount_point: "/remote-storage"
    fstype: "nfs"
    opts: "rw,sync,hard,intr"
  - device: "/dev/sdc1"
    mount_point: "/backup"
    fstype: "xfs"
    opts: "defaults"

🔁 Idempotent Changes Example

• First run — mounts created and mounted
• Second run — removed mount is unmounted and deleted
• Third run — no changes; system already converged

📁 Configuration Files

/etc/fstab

Managed declaratively via ansible.posix.mount.

🧩 Task Breakdown

1️⃣ Initialize & Calculate

• Apply defaults
• Determine removed mounts
• Update managed list

2️⃣ Remove Old Mounts

• Verify mount status
• Unmount if needed
• Remove fstab entry
• Delete directory

3️⃣ Add/Update Mounts

• Create mount directories
• Add/update fstab entries
• Mount filesystems

📚 Ansible Module References

• ansible.builtin.file
• ansible.posix.mount
• ansible.builtin.command
• ansible.builtin.set_fact