Configure a user identifier - Data Collection| Alibaba Cloud Documentation Center

This topic describes how to specify the ID of an Alibaba Cloud account as a user identifier on a server.

Prerequisites

A server is available.
The server can be an Elastic Compute Service (ECS) instance that belongs to another Alibaba Cloud account, a server that is provided by a third-party cloud service provider, or a self-managed data center.
Logtail is installed on the server. For more information, see Install Logtail on a Linux server and Install Logtail on a Windows server.

Background information

If your server is an ECS instance that belongs to another Alibaba Cloud account, a server that is provided by a third-party cloud service provider, or a self-managed data center, you must first install Logtail on the server before you can collect logs from the server. Then, you must specify the ID of the Alibaba Cloud account for which Log Service is activated as a user identifier on the server. This way, the Alibaba Cloud account can use Logtail to collect logs from the server. If you do not configure a user identifier on your server, Log Service cannot receive the heartbeat of the server and Logtail cannot collect logs from the server.

Step 1: Obtain the ID of the Alibaba Cloud account for which Log Service is activated

Use the Alibaba Cloud account for which Log Service is activated to log on to the Alibaba Cloud official website.
Open Cloud Shell.
Run the following command to obtain the ID of the Alibaba Cloud account for which Log Service is activated:
```
echo $ALIBABA_CLOUD_ACCOUNT_ID
```

Step 2: Configure a user identifier

Log on to the server.
Specify the ID that you obtained as a user identifier on the server.
Notice
- If the /etc/ilogtail/users directory does not exist, create the directory.
- After you configure or delete a user identifier, the change takes effect within 1 minute.
- Linux
  In the /etc/ilogtail/users directory, create a file and set the name of the file to the ID of the Alibaba Cloud account.
```
touch /etc/ilogtail/users/17****745
```
- Windows
  In the C:\LogtailData\users directory, create a file and set the name of the file to the ID of the Alibaba Cloud account.
  - Run the following command in Windows PowerShell to create the file:
    ni C:\LogtailData\users\17******745
  - Run the following command in the Command Prompt to create the file:
    type nul > C:\LogtailData\users\17******745

Multiple Alibaba Cloud accounts

If you want to use Log Service that is activated for multiple Alibaba Cloud accounts to collect logs from the same server, you can create multiple user identifier files on the server and configure the IDs of the Alibaba Cloud accounts as user identifiers. Example:

touch /etc/ilogtail/users/17****742
touch /etc/ilogtail/users/17****743

Delete a user identifier

Notice We recommend that you delete user identifier files that you no longer need on a server at the earliest opportunity. Then, Log Service that is activated for the related Alibaba accounts has no permissions to collect logs from the server.

Linux
Run the following command to delete the specified user identifier file:
```
rm /etc/ilogtail/users/17****745
```
Windows
Run the following command to delete the specified user identifier file:
```
del C:\LogtailData\users\17******745
```

What to do next

After you configure the ID of an Alibaba Cloud account as a user identifier on a server, you can create a machine group. For more information, see Create an IP address-based machine group or Create a custom ID-based machine group.