Platform For AI:Deploy a model service by using a custom image

Select an image repository

Authenticate access to an image repository

The required information for authentication varies based on the type of the image repository.

• Container Registry: If you use an Alibaba Cloud account to activate EAS and grant EAS the permissions to access Container Registry, you can use the same account to pull Container Registry Personal Edition or Enterprise Edition images without authentication.

• Self-managed image repository: If your self-managed image repository uses a username and a password as access credentials, you must configure the dockerAuth parameter when you deploy the model service. For more information, see the "Deploy a model service" section of this topic.

Develop a custom image

You can use multiple methods to develop an image. For example, you can use Flask to start a web server. Sample code:

from flask import Flask
 
app = Flask(__name__)
 
@app.route('/hello/model')
def hello_world():
    return 'Hello World'
 
if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)  

You can also use allspark, which is the high-performance serving framework provided by EAS, to develop an image. For more information, see Develop custom processors by using Python.

# -*- coding: utf-8 -*-
import allspark


class MyProcessor(allspark.BaseProcessor):
    def initialize(self):
        """
        This function is only executed once when the service starts, 
        and traffic is not imported until the execution completes. 
        It can be used to load models and service initialization.
        """
        pass

    def process(self, data):
        """
        Each time a request is received, this function is called.
        The input parameter of the function is the request body of the HTTP request, 
        and the function returns two parameters: 
        1. the first parameter will be used as the HTTP response body, 
        2. the second parameter is the HTTP response status code.
        """
        data = 'hello eas'

        return bytes(data, encoding='utf8'), 200

if __name__ == '__main__':
    runner = MyProcessor(endpoint='0.0.0.0:8000')
    runner.run()

After you complete development, you can run the docker build command to build an image that contains your code and use the image for service deployment. Alternatively, you can store the code in an Apsara File Storage NAS (NAS) file system or a Git repository and mount the code during service runtime. For more information, see Mount storage to services (advanced).

Deploy a model service

Preparations

• Obtain the required information to deploy a model service by using a custom image:

  • The address of the image repository. Example: registry-vpc.cn-shanghai.aliyuncs.com/xxx/yyy:zzz.

  • The command to start a container based on the image. Example: /data/eas/ENV/bin/python /data/eas/app.py.

  • The port number of the container that the service listens on. Example: 8000.

    Note

    The port number is optional. For example, if you want the service to accept requests from message queues within the container instead of the EAS gateway, you do not need to specify the port number.

• Prepare the JSON configuration file that is used for service deployment based on the following example.

  You can use the configuration file to deploy a model service by using the EASCMD client or calling API operations. If you deploy a model service in the PAI console, the configuration file is automatically generated based on your interactions with the GUI.

  {
    "name": "image_test",
    "containers": [
      {
        "image": "registry-vpc.cn-shanghai.aliyuncs.com/xxx/yyy:zzz",
        "env": [
          {
            "name": "var_name",
            "value": "var_value"
          }
        ],
        "command": "/data/eas/ENV/bin/python /data/eas/app.py",
        "port": 8000
      }
    ],
    "metadata": {
      "cpu": 1,
      "instance": 1
    }
  }

  The following table describes the parameters in the JSON file.

  Parameter			Required	Description
  containers	image		Yes	The address of the image that you want to use to deploy a model service. Since EAS does not support access over Internet, you must specify the address of the image in the VPC to which EAS is connected. Example: registry-vpc.cn-shanghai.aliyuncs.com.
  	env	name	Yes	The name of the environment variable that is used to start a container based on the image.
  		value	Yes	The value of the environment variable that is used to start a container based on the image.
  	command		Specify one of the two parameters.	The command to run when you start a container. Use this parameter to specify simple commands, such as commands that do not contain /bin/sh. If you want to run complex commands such as cd xxx && python app.py, configure the script parameter.
  	script			The script to run when you start a container. Use this parameter to specify complex commands. Separate multiple lines with \n or semicolons (;).
  	port		No	The port number of the container that the service listens on. Important Do not specify port 8080 and port 9090 because the EAS engine listens on these ports. If you configure the command parameter, set this parameter to the port in the xxx.py file that you specified in the command parameter.
  	prepare	pythonRequirements	No	A list of the packages that you want to install before the container starts. This parameter is valid only when Python and pip commands are available in the system path. Example: "prepare": { "pythonRequirements": [ "numpy==1.16.4", "absl-py==0.11.0" ] }
  		pythonRequirementsPath	No	The path of the requirements.txt file that contains the packages you want to install before the container starts. This parameter is valid only when Python and pip commands are available in the system path. The requirements.txt file can be stored in the image or mounted from a storage. Example: "prepare": { "pythonRequirementsPath": "/data_oss/requirements.txt" }
  	health_check	tcp_socket.port	No	The port number that is used to receive TCP health check requests.
  		http_get.path	No	The HTTP server address that is used to receive HTTP health check requests.
  		http_get.port	No	The port number of the HTTP server that is used to receive HTTP health check requests.
  		initial_delay_seconds	No	The default waiting time before a health check starts. Default value: 3. Unit: seconds.
  		period_seconds	No	The interval between consecutive health check requests. Default value: 3. Unit: seconds.
  		timeout_seconds	No	The timeout period of a health check request. Default value: 1. Unit: seconds. If a health check request does not receive a response within the timeout period, the health check is reported as failed.
  		success_threshold	No	The required number of successful health checks to determine a healthy container. For example, if you set this parameter to 2, a container is considered as healthy after two successful health checks and begins to receive traffic.
  		failure_threshold	No	The required number of failed health checks to determine an unhealthy container. For example, if you set this parameter to 4, a container is considered as unhealthy after four failed health checks and stops receiving traffic.
  dockerAuth			No	The authentication information for the Docker registry. This parameter is required if the image resides in a private image repository. Valid values: username:password in the Base64-encoded format. For example, if the value of username:password is abcd:abcde12345, you can run the echo -n "abcd:abcde12345" | base64 command to Base64-encode the "abcd:abcde12345" string. Then, you can specify the output YWJjZDphYmNkZTEy**** as the value of the dockerAuth parameter.
  metadata			No	The metadata of the service. For more information, see Run commands to use the EASCMD client.
  name			Yes	The name of the service. The name must be unique within a region.

Use the EASCMD client

1. Run the create command on the EASCMD client.

eascmd create image.json

[RequestId]: BFFFE5F5-1F07-437E-B59A-AF1F2B66****
+-------------------+-----------------------------------------------------------------------------------+
| Internet Endpoint | http://182848887922***.cn-shanghai.pai-eas.aliyuncs.com/api/predict/image_test    |
| Intranet Endpoint | http://182848887922***.vpc.cn-shanghai.pai-eas.aliyuncs.com/api/predict/image_test|
|             Token | NjA4MzQxOWQ0MTY2M2Y4OGY0NjgwODkwZTZmYWJmZWU1ZmY0Njhk****                          |
+-------------------+-----------------------------------------------------------------------------------+
[OK] Service is now creating
[OK] Waiting [Total: 2, Pending: 2, Running: 0]
[OK] Running [Total: 2, Pending: 0, Running: 2]
[OK] Service is running

2. If you need to modify service configurations, run the modify command, as shown in the following example.

eascmd modify registry_test -s image.json

Appendix: Sample service configurations

Configure the pythonRequirements parameter

{
  "name": "image_test",
  "containers": [
    {
      "image": "registry-vpc.cn-shanghai.aliyuncs.com/xxx/yyy:zzz",
      "prepare": {
        "pythonRequirements": [
          "numpy==1.16.4",
          "absl-py==0.11.0"
        ]
      },
      "command": "python app.py",
      "port": 8000
    }
  ],
  "metadata": {
    "instance": 1
  }
}

Configure the health_check parameter

{
   "name": "image_test",
   "containers": [
     {
       "image": "registry-vpc.cn-shanghai.aliyuncs.com/xxx/yyy:zzz",
       "command": "python app.py",
       "port": 8000,
       "health_check":{
         "http_get": {
           "path": "/",
           "port": 8000
         },
         "initial_delay_seconds": 3,
         "period_seconds": 3,
         "timeout_seconds": 1,
         "success_threshold": 2,
         "failure_threshold": 4
       }
     }
   ],
   "metadata": {
      "instance": 1
     }
}

Use the gRPC protocol

{
  "name": "image_test",
  "containers": [
    {
      "image": "registry-vpc.cn-shanghai.aliyuncs.com/xxx/yyy:zzz",
      "command": "python app.py",
      "port": 8000
    }
  ],
  "metadata": {
    "instance": 1,
    "enable_grpc": true
  }
}

References

• For information about how deployment works in EAS, see Overview.

• After you deploy a service, you can use the auto scaling feature to handle workload fluctuations in your business. For more information, see Auto scaling.