File Storage NAS:Mount a file system on a Function Compute function

Limits

• You can configure a maximum of five NAS mount targets for a Function Compute function in a region.

• The local directories in the function runtime environment of the NAS mount target cannot conflict with each other.

Configure a NAS file system

1. Log on to the Function Compute console. In the left-side navigation pane, click Functions.

2. In the top navigation bar, select a region. On the Functions page, click the function that you want to manage.

3. On the function details page, click the Configurations tab. In the left-side navigation pane, click Storage. In the NAS section, click Modify. In the NAS panel, configure the following parameters and click Deploy.

   You can select Automatic Configuration or Custom Configuration as the configuration mode to configure a NAS file system.

   Automatic Configuration

   The system automatically creates a general-purpose NAS file system named Alibaba-Fc-V3-Component-Generated, and a VPC, a vSwitch, and a security group with the same name.

   The next time you select Automatic Configuration, the system detects that the preceding NAS file system already exists in the region. In this case, the system reuses the file system and related VPC configurations and does not create the file system again. For more information about billing of VPC and NAS, see Billing and Billing of General-purpose NAS file systems.

   

   Custom Configuration

   If you select this option, you need to manually select a NAS file system, and configure related settings, such as the user, user group, and NAS mount target.

   The following table describes key parameters:

   Parameter	Description	Example
   File Storage NAS	Select an existing NAS file system. To create a new NAS file system, click Create NAS File System below the parameter to go to the NAS console. Important Only Network File System (NFS)-based NAS file systems are supported. Server Message Block (SMB)-based NAS file systems are not supported.	01d394****
   User and User Group	Enter a custom user ID and user group ID. If you do not specify a value, the system root ID is used. Specifically, UID=0 and GID=0. For more information, see NAS users and user groups.	1
   Remote Directory	Specify the remote directory. The remote directory of a general-purpose NAS file system must start with /. The remote directory of an extreme NAS file system must start with /share. If the remote directory you specify does not exist in the remote NAS file system, Function Compute automatically creates the directory for you. The owner of the directory is the preceding user and user group that you configure, and the permission level is 777. For more information, see Remote directory.	/
   Local Function Directory	We recommend that you use a subdirectory of /home, /mnt, /tmp, or /data. Note Do not use common Linux and UNIX system directories and their subdirectories, such as /bin, /opt, /var, or /dev. Otherwise, the mounting may fail. For more information, see Local directory.	/mnt/nas

   

   Note

   • If you want different functions to share NAS file resources, you must use the same user and user group when you configure NAS mounting for these functions.

   • The permissions on files that are uploaded to NAS are the same as those on on-premises files.

Verify whether the NAS file system is mounted

Prepare function code for accessing NAS

After you configure the NAS file system, you can access the NAS file system by using the specified path in your function code.

1. On the function details page, click the Code tab, write code in the code editor, and then click Deploy.

   The following code snippet provides an example of writing data to and read data from a NAS file system by using Python event function code.

   #!/usr/bin/env python
   # -*- coding: utf-8 -*-
   
   import random
   import subprocess
   import string
   import os
   
   
   def handler(event, context):
       # report file system disk space usage and check NAS mount target
       out, err=subprocess.Popen(['df', '-h'], stdout=subprocess.PIPE).communicate()
       print('disk: ' + str(out))
       lines = [ l.decode() for l in out.splitlines() if str(l).find(':') != -1 ]
       nas_dirs = [ x.split()[-1] for x in lines ]
       print('uid : ' + str(os.geteuid()))
       print('gid : ' + str(os.getgid()))
   
       for nas_dir in nas_dirs:
           sub_dir = randomString(16)
           file_name = randomString(6)+'.txt'
           new_dir = nas_dir + '/' + sub_dir + '/'
           print('test file: ' + new_dir + file_name)
           # Write data to the NAS file system.
           content = "NAS here I come"
           os.mkdir(new_dir)
           fw = open(new_dir + file_name, "w+")
           fw.write(content)
           fw.close()
           # Showing the folder tree in NAS
           for home, dirs, files in os.walk(nas_dir):
               level = home.replace(nas_dir, '').count(os.sep)
               indent = ' ' * 2 * (level)
               print('{}{}/'.format(indent, os.path.basename(home)))
               subindent = ' ' * 2 * (level + 1)
               for f in files:
                   print('{}{}'.format(subindent, f))
           # Read data from the NAS file system.
           f = open(new_dir + file_name, "r")
           print(f.readline())
           f.close()
       
       return 'success'
   
   
   def randomString(n):
       return ''.join(random.SystemRandom().choice(string.ascii_uppercase + string.digits) for _ in range(n))
     

Verify the mounting

1. After the code is deployed, click Test Function on the Code tab.

   After the code is executed, you can view the execution result in the lower part of the Code tab. The output logs indicate that the function has successfully written data to and read data from the NAS file system.

   

2. (Optional) After you write and read data, you can log on to the instance to view files in the local directory of the function and check whether the queried NAS file is consistent with the log output of the function.

   1. On the function details page, click the Instances tab and click Connect in the Actions column.

      If no instance is running, you can click Test Function on the Code tab to run the function again and activate an instance.

      

   2. After you log on to the instance, you can run the following command to view files in the local directory of the function: The following figure shows an example.

      

Concepts

References

For more information about the scenarios of NAS storage and the differences between the storage types of Function Compute, see Selection of function storage.