- What's New
- Function Overview
- Product Bulletin
- Service Overview
- Getting Started
-
User Guide
- Overview
- Gateway Management
- API Group Management
- API Management
- Request Throttling
- Access Control
- Environment Management
- Signature Key Management
- VPC Channel Management
- Custom Authorizers
- Plug-ins
- Monitoring
- App Management
- Log Analysis
- SDKs
- Calling Published APIs
- Permissions Management
- Key Operations Recorded by CTS
-
Developer Guide
- Overview
- Authentication Mode Selection
- Calling APIs Through App Authentication
- Calling APIs Through IAM Authentication
- Creating a Function for Frontend Custom Authentication
- Creating a Function for Backend Custom Authentication
- Creating Signatures for Backend Requests
-
Importing and Exporting APIs
- Restrictions and Compatibility
- Extended Definition
- API Import Precautions
- Examples of Importing APIs
- API Export Precautions
-
API Reference
- Before You Start
- Calling APIs
-
Dedicated Gateway APIs (V2)
- API Group Management
- Environment Management
- Environment Variable Management
- Request Throttling Policy Management
-
API Management
- Registering an API
- Modifying an API
- Deleting an API
- Publishing an API or Taking an API Offline
- Querying API Details
- Querying APIs
- Debugging an API
- Publishing APIs or Taking APIs Offline
- Querying Historical Versions of an API
- Switching the Version of an API
- Querying the Runtime Definition of an API
- Querying API Version Details
- Taking an API Version Offline
- Signature Key Management
- Binding/Unbinding Signature Keys
- Binding/Unbinding Request Throttling Policies
- Excluded Request Throttling Configuration
- App Authorization Management
- Resource Query
- App Management
- Domain Name Management
- Access Control Policy Management
- Binding/Unbinding Access Control Policies
- Custom Authorizer Management
- API Import and Export
- VPC Channel Management
- Monitoring Information Query
- Group Response Management
- Tag Management
- Gateway Feature Management
- Configuration Management
-
Gateway Management
- Creating a Dedicated Gateway
- Querying Dedicated Gateway Details
- Updating a Dedicated Gateway
- Querying the Creation Progress of a Dedicated Gateway
- Updating or Binding an EIP to a Dedicated Gateway
- Unbinding the EIP of a Dedicated Gateway
- Enabling Public Access for a Dedicated Gateway
- Updating the Outbound Access Bandwidth of a Dedicated Gateway
- Disabling Public Access for a Dedicated Gateway
- Querying AZs
- Querying Dedicated Gateways
- Deleting a Dedicated Gateway
- Permissions Policies and Supported Actions
- Appendix
- Change History
- SDK Reference
- Best Practices
-
FAQs
- Common FAQs
-
API Creation
- Why Can't I Create APIs?
- How Do I Define Response Codes for an API?
- How Do I Specify the Host Port for a VPC Channel (or Load Balance Channel)?
- How Do I Set the Backend Address If I Will Not Use a VPC Channel (or Load Balance Channel)?
- How Can I Configure the Backend Service Address?
- Can I Specify a Private Network Load Balancer Address for the Backend Service?
- Can I Specify the Backend Address as a Subnet IP Address?
- Does APIG Support Multiple Backend Endpoints?
- What Should I Do After Applying for an Independent Domain Name?
- Can I Bind Private Domain Names for API Access?
- Why Does an API Failed to Be Called Across Domains?
-
API Calling
- What Are the Possible Causes for an API Calling Failure?
- What Should I Do If an Error Code Is Returned During API Calling?
- Why Am I Seeing the Error Message "414 Request-URI Too Large" When I Call an API?
- What Should I Do If "The API does not exist or has not been published in the environment." Is Displayed?
- Why Am I Seeing the Message "No backend available"?
- What Are the Possible Causes If the Message "Backend unavailable" or "Backend timeout" Is Displayed?
- Why Am I Seeing the Message "Backend domain name resolution failed" When a Backend Service Is Called?
- Why Doesn't Modification of the backend_timeout Parameter Take Effect?
- How Do I Switch the Environment for API Calling?
- What Is the Maximum Size of an API Request Package?
- How Do I Perform App Authentication in iOS System?
- Why Can't I Create a Header Parameter Named x-auth-token for an API Called Through IAM Authentication?
- App FAQs
- Can Mobile Apps Call APIs?
- Can Applications Deployed in a VPC Call APIs?
- How Do I Implement WebSocket Data Transmission?
- Does APIG Support Persistent Connections?
- How Will the Requests for an API with Multiple Backend Policies Be Matched and Executed?
- Is There a Limit on the Size of the Response to an API Request?
- How Can I Access Backend Services over Public Networks Through APIG?
-
API Authentication
- Does APIG Support HTTPS Two-Way Authentication?
- How Do I Call an API That Does Not Require Authentication?
- Which TLS Versions Does APIG Support?
- Does APIG Support Custom Authentication?
- Will the Request Body Be Signed for Security Authentication?
- Common Errors Related to IAM Authentication Information
- API Control Policies
- API Publishing
- API Import and Export
- API Security
-
Other FAQs
- What Are the Relationships Between an API, Environment, and App?
- How Can I Use APIG?
- What SDK Languages Does APIG Support?
- Can I Upload Files Using the POST Method?
- What Are the Error Messages Returned by APIG Like?
- How Do I Use APIG to Open Up Services Deployed on Huawei Cloud?
- Can APIG Be Deployed in a Local Data Center?
- Videos
Can Applications Deployed in a VPC Call APIs?
Yes, applications deployed in a VPC can call APIs by default. If domain name resolution fails, configure a DNS server on the current endpoint by following the instructions in Configuring an Intranet DNS Server. After the configuration, applications deployed in the VPC can call APIs.
Configuring an Intranet DNS Server
To configure a DNS server, specify its IP address in the /etc/resolv.conf file.
The IP address of the intranet DNS server depends on which region you are located in. Find the IP address of the intranet DNS server in your region from the private DNS server addresses mentioned in the Domain Name Service FAQs.
Add an intranet DNS server with either of the following two methods:
- Method 1: Modify the subnet information of the VPC.
- Method 2: Edit the /etc/resolv.conf file.
NOTE:
The intranet DNS server configurations become invalid after the ECS restarts, and the intranet DNS server must be configured again. Therefore, method 1 is recommended.
Method 1
Perform the following procedure to add a DNS server IP address to the subnet configurations of the ECS in the VPC.
- Log in to the management console.
- Click
in the upper left corner to select a region.
- In the service list, choose Compute > Elastic Cloud Server.
- Click the name of the ECS you want to use.
- On the ECS details page, view the NIC information, and click
to view the subnet name of the ECS.
- On the ECS basic information page, view the VPC name of the ECS.
- Click the VPC name to visit the VPC console.
- Choose Subnets in the left navigation pane.
- Locate the subnet mentioned in 5 and click the subnet name.
- Change the DNS server address of the subnet and click OK.
For example, change the address to 100.125.1.250.
- Restart the ECS. Check that the /etc/resolv.conf file contains the IP address of the DNS server to be configured, and the IP address is less than those of all other DNS servers.
The following figure shows the IP address 100.125.1.250 of the DNS server to be configured.
NOTE:
Modifying the subnet information of a VPC will affect all ECSs created using the subnet.
Method 2
Add the IP address of the intranet DNS server to the /etc/resolv.conf file.
For example, if you are located in EU-Dublin, add an intranet DNS server of IP address 100.125.1.250 to the /etc/resolv.conf file.
- The IP address of the new DNS server must be less than those of all other DNS servers.
- The DNS configurations take effect immediately after the /etc/resolv.conf file is saved.
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