Configure custom DNS

Prerequisites

Before you begin, ensure that you have:

• A function created in Function Compute (Custom Image functions are not supported; GPU-accelerated functions are not supported)

Configure DNS settings

1. Log on to the Function Compute console. In the left-side navigation pane, choose Function Management > Function.

2. In the top navigation bar, select a region. On the Function page, click the target function.

3. On the function details page, click the Configuration tab. To the right of Advanced Settings, click Modify.

4. In the Advanced Settings panel, locate the DNS section and configure the following parameters:

   Parameter	Description	Example
   Name servers	IP addresses of the DNS servers. Add multiple addresses as needed. To use the default Function Compute DNS servers, add 100.100.2.136 and 100.100.2.138.	223.5.5.5, 223.6.6.6
   Search domain	DNS search domains. Add multiple domains as needed. When a domain name fails to resolve, the system appends each search domain in order and retries the query.	example.com
   DNS options	Additional resolver options in key:value format. The key is required.	attempts:1

5. Click Deploy.

Verify the configuration

After deploying, confirm that your custom DNS settings are active by running a test function.

1. On the function details page, click the Code tab.

2. In the code editor, paste the following sample code:

   import logging
   import subprocess
   
   def handler(event, context):
     logger = logging.getLogger()
     f = open('/etc/resolv.conf')
     logger.info("".join(f.readlines()))
     f.close()
     output = subprocess.check_output(["ping", "-c", "1", "www.aliyun.com"])
     return output

3. Click Deploy, then click Test Function.

4. Review the results:

   • Response: view the content generated for resolv.conf.

   • Log Output: view the IP address of the returned domain name.