Assistant: 
User: User: help me write a bash script that checks whether there are any stale nfs mounts om my local machine, and if yes, restart the nfs mount service on the remote machine
Assistant: To create a bash script that checks for stale NFS mounts on your local machine and restarts the NFS service on the remote machine if any are found, you'll need to follow these steps:

1. **Check for Stale NFS Mounts**: Use the `df` command or `/proc/mounts` to list mounted filesystems and identify any stale mounts.

2. **Restart the NFS Service on Remote Machine**: Use SSH to connect to the remote server and restart the NFS service.

Here is an example script that performs these tasks:

```bash
#!/bin/bash

# Define variables
REMOTE_SERVER="remote.server.address"  # Replace with your remote server address
REMOTE_USER="username"                 # Replace with your username for SSH access
NFS_SERVICE_NAME="nfs-server"          # Change if your service name differs

# Function to check for stale NFS mounts
check_stale_nfs_mounts() {
    # List all mounted filesystems and filter for 'stale' entries using grep.
    STALE_MOUNTS=$(grep nfs /proc/mounts | awk '{print $2}' | xargs -I {} timeout 1 ls {} >/dev/null 2>&1 || echo "{}")
    
    if [ -n "$STALE_MOUNTS" ]; then
        echo "Stale NFS mounts detected:"
        echo "$STALE_MOUNTS"
        return 0   # Indicates stale mounts were found.
    else
        echo "No stale NFS mounts detected."
        return 1   # Indicates no stale mounts were found.
    fi
}

# Function to restart the nfs service on a remote machine via SSH
restart_remote_nfs_service() {
    echo "Attempting to restart NFS service on $REMOTE_SERVER..."
    
    ssh "${REMOTE_USER}@${REMOTE_SERVER}" << EOF 
sudo systemctl restart ${NFS_SERVICE_NAME}
EOF

    if [ $? -eq 0 ]; then 
      echo "Successfully restarted NFS service on $REMOTE_SERVER."
    else 
      echo "Failed to restart NFS service. Please check connectivity or permissions."
      exit 1 
	fi  
}

# Main logic of the script

if check_stale_nfs_mounts; then
	restart_remote_nfs_service	
else 
	echo "No action needed."	
fi 

exit 0 

```

### Notes:
- **Remote Access**: Ensure you have SSH access set up between your local machine and the remote server
User: Great, then please add a step that remounts the stale nfs mounts if a restart was done successfully
Assistant: Certainly! To add functionality that remounts the stale NFS mounts if the NFS service was restarted successfully, you can modify the script to include a function that remounts the stale NFS paths. Below is the updated script with this functionality:

```bash
#!/bin/bash

# Define variables
REMOTE_SERVER="remote.server.address"  # Replace with your remote server address
REMOTE_USER="username"                 # Replace with your username for SSH access
NFS_SERVICE_NAME="nfs-server"          # Change if your service name differs

# Function to check for stale NFS mounts
check_stale_nfs_mounts() {
    # List all mounted filesystems and filter for 'stale' entries using grep.
    STALE_MOUNTS=$(grep nfs /proc/mounts | awk '{print $2}' | xargs -I {} timeout 1 ls {} >/dev/null 2>&1 || echo "{}")
    
    if [ -n "$STALE_MOUNTS" ]; then
        echo "Stale NFS mounts detected:"
        echo "$STALE_MOUNTS"
        return 0   # Indicates stale mounts were found.
    else
        echo "No stale NFS mounts detected."
        return 1   # Indicates no stale mounts were found.
    fi
}

# Function to restart the NFS service on a remote machine via SSH
restart_remote_nfs_service() {
    echo "Attempting to restart NFS service on $REMOTE_SERVER..."
    
    ssh "${REMOTE_USER}@${REMOTE_SERVER}" << EOF 
sudo systemctl restart ${NFS_SERVICE_NAME}
EOF

    if [ $? -eq 0 ]; then 
      echo "Successfully restarted NFS service on $REMOTE_SERVER."
      return 0
    else 
      echo "Failed to restart NFS service. Please check connectivity or permissions."
      return 1
	fi  
}

# Function to remount stale NFS mounts
remount_stale_nfs() {
    echo "Remounting stale NFS mounts..."
    
    for mount in $STALE_MOUNTS; do
        sudo umount "$mount"
        if [ $? -eq 0 ]; then
            sudo mount "$mount"
            if [ $? -eq 0 ]; then
                echo "Successfully remounted $mount."
            else
                echo "Failed to remount $mount."
            fi
        else
            echo "Failed to unmount $mount. Please check manually."
        fi
    done
}

# Main logic of the script

if check_stale_nfs_mounts; then
    if restart_remote_nfs_service; then
        remount_stale_nfs
    else
        echo "NFS service restart failed, cannot remount. Aborting."
    fi
else 
    echo "No action needed."
fi 

exit 0
```

### Important Notes:
- **Privilege**: The script uses `sudo` for unmounting and remounting, so you'll need appropriate permissions. You might need to configure your `sudoers` file to allow these commands without a password if you wish to run the script non-interactively.
- **Error Handling**: Basic error handling is included but could be expanded upon. It currently reports failures to mount or unmount.
- **Testing**: Before using this in a production environment, test it on a non-critical system to ensure it behaves as expected with your specific setup.

Double-check your NFS service name and update any variables as needed for your specific environment.
User: The part of the script checking for stale mounts need to be changed, when the mount is stale, nothing is mounted. So checking /proc/mounts returns nothing
Assistant:
Assistant: