Use an ECS instance that runs Ubuntu to configure a reverse proxy for access to OSS - Best Practices| Alibaba Cloud Documentation Center

The IP address used to access an Object Storage Service (OSS) bucket dynamically changes. You can configure a reverse proxy on an Elastic Compute Service (ECS) instance to access the OSS bucket by using a static IP address.

Background information

OSS uses Restful APIs to provide services. You can access a bucket by using the default endpoint of the bucket or custom domain names that are mapped to the bucket. However, you may need to use a static IP address to access OSS in some scenarios.

For security reasons, some enterprises must configure outbound rules to specify that internal employees and business systems can access only the specified public IP addresses. However, the IP addresses used to access a bucket in OSS dynamically change. In this case, enterprises must frequently modify firewall rules.
Limited by the network architecture of Alibaba Finance Cloud, internal network-specific buckets in Alibaba Finance Cloud can be accessed only by requests from Alibaba Finance Cloud but not those from the Internet.

To resolve these issues, you can use an ECS instance to configure a reverse proxy for access to OSS.

Procedure

Create an ECS instance that runs Ubuntu. Make sure that the instance and the bucket you want to access are located within the same region.
The Ubuntu 18.04 (64-bit) system is used in this example. For more information, see Create an ECS instance.
Log on to the ECS instance as the root user. Update the APT sources.
```
root@test:~# apt-get update
```

Install NGINX.

root@test:~# apt-get install nginx

Note By default, the files of NGINX are installed in the following paths:

 /usr/sbin/nginx       Stores the NGINX executable. 
 /etc/nginx            Stores configuration files. 
 /usr/share/nginx      Stores static files. 
 /var/log/nginx        Stores log files.

Open the configuration file of NGINX.
```
root@test:~# vi /etc/nginx/nginx.conf
```
Add the following content to the http context of the configuration file:
```
server {
        listen 80;
        server_name 47.**.**.73; 

        location / {
            proxy_pass http://bucketname.oss-cn-beijing-internal.aliyuncs.com; 
            #proxy_set_header Host $host; 
     }  
}
```
- server_name: the IP address used to provide the reverse proxy service, which is the public IP address of the ECS instance.
- proxy_pass: the endpoint for redirection.
  - When the ECS instance and the bucket that you want to access are located within the same region, specify the internal endpoint of the bucket. For more information about endpoints, see OSS domain names.
  - When the ECS instance and the bucket that you want to access are located in different regions, specify the public endpoint of the bucket.
  - For security reasons, when you access an image or web page object in a bucket by using the default domain name of the bucket in a browser, the object is downloaded. To preview the object in your browser, map a custom domain name to the bucket in which the object is stored and add the custom domain name to the value of proxy_pass. For more information about how to map a custom domain name to a bucket, see Map custom domain names.
- proxy_set_header Host $host: If you add this parameter, the host value is replaced with the IP address of the ECS instance when NGINX sends a request to OSS. You must add this parameter in the following scenarios:
  - Signature errors occur.
  - The custom domain name that is mapped to the bucket is resolved to the public IP address of the ECS instance. You must preview image or web page objects in the bucket by using a browser. You can map the custom domain name to the bucket for which a reverse proxy is configured without adding a CNAME record for the custom domain name. In this case, you can set proxy_pass to the internal or public endpoint of the bucket. For more information about how to map a custom domain name to a bucket, see Map custom domain names.
Notice
- A demo environment is used in this topic as an example. For data security reasons, we recommend that you configure the https context. For more information, see Configure HTTPS for your custom domain name in OSS by using reverse proxy.
- You can configure a reverse proxy for only one bucket if you use this configuration method.
Go to the directory in which the NGINX executable file is located. Start NGINX.
```
root@test:~# cd /usr/sbin/
root@test:~# ./nginx
```
Enable TCP port 80 of the ECS instance.
By default, NGINX uses TCP port 80. Therefore, you must enable TCP port 80 when you configure a security group for the ECS instance. For more information, see Add security group rules.
Add the object path to the public IP address of the ECS instance to access OSS resources.

References

Use an ECS instance that runs CentOS to configure a reverse proxy for access to OSS