Simple Log Service:How do I troubleshoot an error that is related to a Logtail machine group in a host environment?

Examples of machine group installation

• If an Elastic Compute Service (ECS) instance and your Simple Log Service project belong to the same Alibaba Cloud account and reside in the same region, create a machine group by following the instructions in Install Logtail and create a machine group.

• If an ECS instance and your Simple Log Service project belong to different Alibaba Cloud accounts, an ECS instance and your Simple Log Service project belong to the same Alibaba Cloud account but reside in different regions, and in scenarios involving other clouds and self-managed servers, create a machine group by following the instructions in Create a machine group.

Troubleshooting preview

1. Step 1: Check whether Logtail runs as expected: Check whether Logtail runs as expected on the server.

2. Step 2: Check whether the IP address that is specified in the machine group is the same as the IP address that is obtained by Logtail: Check whether the IP address that is specified in the machine group is the same as the IP address in the app_info.json file of Logtail. If the IP addresses are different, a heartbeat failure occurs.

3. Step 3: Check whether the Logtail startup parameters are valid: Check whether the region that is specified in the ilogtail_config.json file is supported.

4. Step 4: Check whether network connectivity is available: Check whether the server can connect to the address of the project.

5. Step 5: Check whether the system time of the server on which Logtail is installed is correct: If the system time is earlier or later than the local time, you must change the system time.

6. Step 6: Check whether a user identifier is configured: If an ECS instance and your Simple Log Service project belong to different Alibaba Cloud accounts, an ECS instance and your Simple Log Service project belong to the same Alibaba Cloud account but reside in different regions, and in scenarios involving other clouds and self-managed servers, you must check whether a user identifier is configured.

7. Step 7: Check whether a custom identifier is configured if you use a custom identifier-based machine group: If you use a custom identifier-based machine group, check whether a custom identifier is configured.

8. Step 8: Restart Logtail: After you perform the preceding operations, you must restart Logtail.

What to do next

If no logs are collected after the heartbeat status changes to OK, you can troubleshoot the issue based on the Logtail errors. For more information, see How do I view Logtail collection errors?

Step 1: Check whether Logtail runs as expected

1. Obtain the value of the ip field in the app_info.json file.

   The following table describes the default paths to the app_info.json file in different operating systems.

   Operating system	Logtail	Path to the app_info.json file
   Linux	Logtail for 64-bit Linux	/usr/local/ilogtail/app_info.json
   64-bit Windows	Logtail for 64-bit Windows	C:\Program Files\Alibaba\Logtail\app_info.json
   	Logtail for 32-bit Windows	C:\Program Files (x86)\Alibaba\Logtail\app_info.json
   32-bit Windows	Logtail for 32-bit Windows	C:\Program Files\Alibaba\Logtail\app_info.json

   The value of the ip field specifies the IP address that is obtained by Logtail.

   {
     "UUID" : "",
     "hostname" : "iZ8vbdlzf******azuhZ",
     "instance_id" : "E9633380-***********-00163E1AA597_172.16.2.200_166****11",
     "ip" : "172.**.**.200",
     "logtail_version" : "1.3.1",
     "os" : "Linux; 4.19.91-26.1.al7.x86_64; #1 SMP Tue Jul 26 17:52:28 CST 2022; x86_64",
     "update_time" : "2022-12-27 05:38:33"
   }

2. Check whether the IP address that is specified in the machine group is the same as the IP address that is obtained by Logtail.

   Simple Log Service machine groups are classified into IP address-based machine groups and custom identifier-based machine groups. For more information, see Introduction to machine groups.

   • IP address-based machine group: Check whether the IP address obtained in the previous step is included in the value of the IP Address field.

     If the value of the IP Address field is another IP address of Logtail such as a public IP address, change the value to the IP address that is obtained by Logtail. Then, check whether the heartbeat of the machine group can be detected. If the heartbeat can be detected, you can stop troubleshooting.

   • Custom identifier-based machine group: Check whether the IP address obtained in the previous step is included in the Machine Group Status section. If the heartbeat status is OK, you can stop troubleshooting.

The ilogtail_config.json file records the startup parameters of Logtail.

1. Log on to the server on which Logtail is installed.

2. Find the ilogtail_config.json file.

   The following table describes the default paths to the ilogtail_config.json file in different operating systems.

   Operating system	Logtail	Path to the ilogtail_config.json file
   Linux	Logtail for 64-bit Linux	/usr/local/ilogtail/ilogtail_config.json
   64-bit Windows	Logtail for 64-bit Windows	\ilogtail_config.json
   	Logtail for 32-bit Windows	C:\Program Files (x86)\Alibaba\Logtail\ilogtail_config.json
   32-bit Windows	Logtail for 32-bit Windows	C:\Program Files\Alibaba\Logtail\ilogtail_config.json

   1. Open the ilogtail_config.json file and check whether the parameters in the configuration file are valid.

      {
        "config_server_address" : "http://logtail.<config_region>.log.aliyuncs.com",
        "data_server_list" :
        [
          {
            "cluster" : "<Region to which the project belongs>",
            "endpoint" : "<endpoint>"
          }
        ],
        ...
      }

      • If the configurations of the startup parameters in the ilogtail_config.json file comply with the descriptions in the following table, the startup parameters of Logtail are valid.

      • If the startup parameters of Logtail are invalid, modify the ilogtail_config.json file based on the descriptions in the following table and restart Logtail. For more information, see Restart Logtail.

        For more information about the supported regions, see Supported regions.

        Scenario	Network type	<config_region>	<endpoint>
        The server is an ECS instance that resides in the same region as the project.	Alibaba Cloud internal network	<Region to which the project belongs>-intranet	<Region to which the project belongs>-intranet.log.aliyuncs.com
        Other scenarios	Internet	<Region to which the project belongs>	<Region to which the project belongs>.log.aliyuncs.com
        	Transfer acceleration		log-global.aliyuncs.com

Logtail can upload data to Simple Log Service only if the server on which Logtail is installed can connect to the following addresses.

1. The address that is specified by the config_server_address field in the ilogtail_config.json file. Only the HTTPS version specified by the field value is supported.

2. The address in the http://<Project name>.<endpoint> format.

   • You can view the name and the region of the project by following the instructions in the figure.

     

   • <endpoint> is the address that is specified by the data_server_list.endpoint field in the ilogtail_config.json file.

3. The address in the http://ali-<Region to which the project belongs>-sls-admin.<endpoint> format. <endpoint> is the address that is specified by the data_server_list.endpoint field in the ilogtail_config.json file.

To check whether network connectivity is available, perform the following operations:

Linux

1. Log on to the server on which Logtail is installed.

2. Run the date command to view the system time:

   Wed Dec 28 06:59:26 UTC 2022

   If the system time is earlier or later than the local time, perform the following operations:

   • Change the system time to the local time.

   • If you cannot change the system time, add "enable_log_time_auto_adjust": true to the ilogtail_config.json file. After you modify the file, restart Logtail. For more information, see Restart Logtail. For more information about the path to the ilogtail_config.json file, see Step 3: Check whether the Logtail startup parameters are valid.

Windows

1. Log on to the server on which Logtail is installed.

2. View the time information in the taskbar in the lower-right corner of the desktop.

   • Change the system time to the local time.

   • If you cannot change the system time, add "enable_log_time_auto_adjust": true to the ilogtail_config.json file. After you modify the file, restart Logtail. For more information, see Restart Logtail. For more information about the path to the ilogtail_config.json file, see Step 3: Check whether the Logtail startup parameters are valid.

Step 6: Check whether a user identifier is configured

You can use a user identifier file in a specified directory to check whether a user identifier is configured. If the output is empty, you must check whether a user identifier file exists in a specified directory.

• If no user identifier file exists in the specified directory or a user identifier file is invalid, perform the following operations to fix the issue:

  • Linux: Run the cd /etc/ilogtail/users/ && touch <uid> command to create a user identifier file. <uid> specifies the ID of the Alibaba Cloud account to which the project belongs.

  • Windows: Go to the C:\LogtailData\users\ directory and create an empty file named <uid>. <uid> specifies the ID of the Alibaba Cloud account to which the project belongs.

• If the specified directory contains a file named based on the ID of the Alibaba Cloud account to which the project belongs, the user identifier is configured and valid.

Step 7: Check whether a custom identifier is configured if you use a custom identifier-based machine group

You can use the user_defined_id file in a specified directory to check whether a custom identifier is configured for your server.

• If the output is empty, you must check whether the user_defined_id file exists or whether a custom identifier is configured in the file.

  Note

  The path to the user_defined_id file varies based on the operating system.

  • Linux: /etc/ilogtail/user_defined_id

  • Windows: C:\LogtailData\user_defined_id

  • If the user_defined_id file does not exist, create a file named user_defined_id and add the custom identifier of the machine group to the file. For more information, see Configure a custom identifier for your servers.

  • If no custom identifier exists in the user_defined_id file or the custom identifier is invalid, add a line to the file and enter the custom identifier of the machine group. For more information, see Configure a custom identifier for your servers.

  • If the user_defined_id file contains the custom identifier that you configured for the machine group, the custom identifier is configured and valid.

Step 8: Restart Logtail

After you perform the preceding operations, you must restart Logtail.