how to configure DNS settings for Cloud Assistant-Elastic Compute Service(ECS)-阿里云帮助中心

Add Cloud Assistant endpoint IP addresses to the hosts file to restore DNS resolution when custom DNS settings break it.

Use cases

Cloud Assistant requires access to its service endpoints to run commands on ECS instances. The default DNS nameserver on ECS instances resolves these endpoints without additional configuration.

If you overwrite the default DNS nameserver settings, endpoint resolution may fail or slow down, making Cloud Assistant unavailable. In this case, manually configure DNS resolution to restore Cloud Assistant.

Run the following command for your OS to check the current DNS nameserver. If the output shows non-default settings, configure DNS resolution for Cloud Assistant.

Linux instance

Run the cat /etc/resolv.conf command to view the DNS nameserver settings.

default-nameserver

Windows instance

Run the nslookup command in Windows PowerShell to view the DNS nameserver settings.

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Procedure

Linux instance

Connect to the Linux instance.
Obtain the IP addresses that correspond to Cloud Assistant endpoints.
Cloud Assistant uses the following endpoints:
- Command execution: <region-id>.axt.aliyun.com
- Plug-in and update packages: aliyun-client-assist-<region-id>.oss-<region-id>-internal.aliyuncs.com
  
  Note
  Replace <region-id> with your region ID. See Regions and zones.
For example, to obtain the endpoint IP addresses for the China (Beijing) region, run the following commands:
```
ping -c 4 cn-beijing.axt.aliyun.com
ping -c 4 aliyun-client-assist-cn-beijing.oss-cn-beijing-internal.aliyuncs.com
```

Modify the hosts file.

echo "100.100.XX.XX cn-beijing.axt.aliyun.com" >> /etc/hosts && \
echo "100.118.XX.XX aliyun-client-assist-cn-beijing.oss-cn-beijing-internal.aliyuncs.com" >> /etc/hosts

Note

Replace 100.100.XX.XX and 100.118.XX.XX with the IP addresses that you obtained in Step 2.

Verify the hosts file update.
```
cat /etc/hosts
```
The output shows the updated hosts file entries.
The instance now resolves Cloud Assistant endpoints using the IP addresses in the hosts file.

Windows instance

Connect to the Windows instance.
Obtain the Cloud Assistant endpoint IP addresses.
Cloud Assistant uses the following endpoints:
- Command execution: <region-id>.axt.aliyun.com
- Plug-in and update packages: aliyun-client-assist-<region-id>.oss-<region-id>-internal.aliyuncs.com
  
  Note
  Replace <region-id> with your region ID. See Regions and zones.
For example, to obtain the endpoint IP addresses for the China (Beijing) region, run the following commands in Windows PowerShell:
```
ping cn-beijing.axt.aliyun.com
ping aliyun-client-assist-cn-beijing.oss-cn-beijing-internal.aliyuncs.com
```

Run the following commands in Windows PowerShell to modify the hosts file:

"100.100.XX.XX cn-beijing.axt.aliyun.com" | Add-Content C:\Windows\System32\drivers\etc\hosts
"100.118.XX.XX aliyun-client-assist-cn-beijing.oss-cn-beijing-internal.aliyuncs.com" | Add-Content C:\Windows\System32\drivers\etc\hosts

Note

Replace 100.100.XX.XX and 100.118.XX.XX with the IP addresses that you obtained in Step 2.

Verify the hosts file update.
```
cat C:\Windows\System32\drivers\etc\hosts
```
The output shows the updated hosts file entries.
The instance now resolves Cloud Assistant endpoints using the IP addresses in the hosts file.