Function Compute (2.0):Configure custom DNS settings for functions

Limits

The custom DNS feature supports only the runtimes and custom runtimes that are provided by Function Compute.

Prerequisites

Create a function

Configure custom DNS settings

1. Log on to the Function Compute console.
2. In the left-side navigation pane, click Services & Functions.
3. In the top navigation bar, select a region.
4. On the Services page, click the desired service.
5. On the Functions page, find the function that you modify and click Configure in the Actions column.
6. In the DNS Configuration section, configure the parameters and click Save. The following table describes the parameters.
   

   Parameter	Description	Example
   Name Servers	The IP addresses of the DNS servers. You can add the IP addresses of one or more DNS servers.	223.5.5.5 223.6.6.6
   Search Domain	The DNS search domains. You can add one or more search domains. If the accessed domain name cannot be resolved by DNS, the search domain is appended to the domain name, and then the accessed domain name is resolved again.	mydomain.com
   DNS Options	The configuration items in the resolv.conf file. Each item corresponds to a key-value pair in the key:value format, in which the key is required.	attempts:1

7. Verify whether the custom DNS settings that you configured take effect.
   1. On the details page of the function, click the Code tab.
   2. Write code in the code editor, click Deploy, and then click Test Function.
      Sample Python 3 code:

      # -*- coding: utf-8 -*-
      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. On the Code tab, view the execution result. In the Response section, view the content that is generated based on the resolv.conf file. In the Log Output section, view the returned IP addresses of the domain name.