---
title: "SSH Service Account"
slug: "fmadio-os-authentication-ssh-service-account"
updated: 2026-03-19T10:56:52Z
published: 2026-03-19T10:56:52Z
canonical: "docs.fmad.io/fmadio-os-authentication-ssh-service-account"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fmad.io/llms.txt
> Use this file to discover all available pages before exploring further.

# SSH Service Account

By default the linux “fmadio” account is the default user account and can not be removed. Additional SSH user accounts can be added to the system, below are the specific steps.

## Step 1) Create the account

Create the account using the usual linux command `adduser` In the below examples the account is named “service” this can be changed freely.

Run the command to create the account

```plaintext
sudo adduser service -G staff
```

Example output

```plaintext
fmadio@fmadio200v4-636:~$ sudo adduser service -G staff
Changing password for service
New password:
Bad password: too short
Retype password:
passwd: password for service changed by root
fmadio@fmadio200v4-636:~$
```

### Step 2) Create .ssh directory (optional)

To create an SSH Key based login

Change to be the `service` user

```plaintext
sudo su service
```

Then create the `.ssh ` directory

```plaintext
cd
mkdir .ssh
```

Typically create an authorized_key file for password / key based login

```plaintext
vi .ssh/authorized_keys
```

Then paste in the public access keys

Full command shown below

```plaintext
service@fmadio200v4-636:/home/fmadio$ cd
service@fmadio200v4-636:~$ mkdir .ssh
service@fmadio200v4-636:~$ pwd
/home/service
```

**The usual Linux / Bash shell configuration can be done here**

### Step 3) Enable sudo

Edit the `sudoers` files to allow the service account run sudo

```plaintext
sudo vi /etc/sudoers
```

Then add the new user account, example shown below for `service`

```plaintext
service@fmadio200v4-636:~$ sudo cat /etc/sudoers
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the man page for details on how to write a sudoers file.
#

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL) ALL
fmadio  ALL=NOPASSWD: ALL
service ALL=NOPASSWD: ALL
service@fmadio200v4-636:~$
```

### Step 4) Copy system files for persistence

The system files need to be persisted, otherwise the service account will not be preserved

Copy the home directory

```plaintext
sudo mkdir /mnt/store0/home/
sudo cp -Rp /home/service /mnt/store0/home/
```

Copy the system files

```plaintext
sudo cp /etc/passwd /opt/fmadio/etc/
sudo cp /etc/sudoers /opt/fmadio/etc/
```

### Step 5) Update boot.lua (prior FW 11843)

For **firmware prior to Version 11843** the following needs to be added to the `boot.lua` file. Firmware Version 11843+ does this automatically and this step is not required.

Edit the file

```plaintext
/opt/fmadio/etc/boot.lua
```

Append these lines at the end of the file

```plaintext
-- service account
os.execute([[cp -Rp /mnt/store0/home/* /home/]])
os.execute([[cp /opt/fmadio/etc/passwd /etc/]])
os.execute([[cp /opt/fmadio/etc/sudoers /etc/]])
```

### Step 6) Reboot

After reboot, confirm login using the service account works correctly.