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

Step 1: Check whether Logtail runs as expected

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

Logtail obtains a server IP address by using one of the following methods:

• If the hostname of the server is not mapped to an IP address, Logtail obtains the IP address of the first network interface controller (NIC) of the server.

• If the hostname of the server is mapped to an IP address, Logtail obtains the IP address from the /etc/hosts file of the server. The /etc/hosts file includes hostname-IP address mapping settings.

To check whether the IP address that is specified in the machine group is the same as the IP address that is obtained by Logtail, perform the following operations:

1. Open the app_info.json file.

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

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

   {
     "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"
   }

3. 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.

   • If you use an IP address-based machine group, view the IP address in the IP Address field. For more information, see Manage machine groups.

     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.

   • If you use a custom identifier-based machine group, use the IP address that is obtained by Logtail to query the status of the machine group. For more information, see Manage machine groups. If the heartbeat status is OK, you can stop troubleshooting.

Step 3: Check whether the Logtail startup parameters are valid

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.

   Run the following command to check whether the path to the file can be obtained from the environment variable:

   echo $ALIYUN_LOGTAIL_CONFIG

   If the output is empty, the path to the file cannot be obtained from the environment variable. You can use one of the following default paths to find the ilogtail_config.json file.

   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	C:\Program Files\Alibaba\Logtail\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 Appendix: Restart Logtail.

        Scenario	Network type	<config_region>	<endpoint>
        The server is an Elastic Compute Service (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

   Step 4: Check whether network connectivity is available

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

   Important

   If you use an internal network, you must add -intranet to the end of <endpoint>.

   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. <endpoint> is the address that is specified by the data_server_list.endpoint field in the ilogtail_config.json file. You can view the <Project name> and <endpoint> on the Simple Log Service console.

   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 curl command to connect to the preceding addresses in sequence.

      curl xxx

      If each output contains information that is similar to the following code, network connectivity is available.

      {"Error":{"Code":"OLSInvalidMethod","Message":"The script name is invalid : /","RequestId":"5D****09"}}

      If network connectivity is unavailable, check whether ports 80 and 443 in the network environment are enabled, whether the destination address is blocked, and whether other network-side configurations such as Domain Name System (DNS) configurations and security groups are valid.

   Windows

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

   2. Run the telnet command to connect to the preceding addresses in sequence.

      telnet xxx 80 # If HTTPS is used, specify port 443.

      If each output contains information that is similar to the following code, network connectivity is available.

      Trying 100*0*7*5...
      Connected to xxx.
      Escape character is '^]'.

      If network connectivity is unavailable, check whether ports 80 and 443 in the network environment are enabled, whether the destination address is blocked, and whether other network-side configurations such as DNS configurations and security groups are valid.

   Step 5: Check whether the system time of the server on which Logtail is installed is correct

   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 Appendix: 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 Appendix: 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

   Important

   A user identifier must be the ID of an Alibaba Cloud account. For more information, see Obtain the ID of the Alibaba Cloud account for which Simple Log Service is activated.

   You can use the ALIYUN_LOGTAIL_USER_ID environment variable or a user identifier file in a specified directory to check whether a user identifier is configured. If a user identifier is configured by using the environment variable, the configuration of the environment variable takes precedence. You can run the following command to check whether the user identifier is configured by using the environment variable:

   echo $ALIYUN_LOGTAIL_USER_ID

   • If the output contains the ID of the Alibaba Cloud account to which the project belongs, the user identifier is configured and valid.

   • If the output is not empty but does not contain the ID of the Alibaba Cloud account to which the project belongs, you must change the value of the environment variable to the ID of the Alibaba Cloud account to which the project belongs or append the ID to the existing value. Separate multiple IDs with commas (,).

   • If the output is empty, you must check whether a user identifier file exists in a specified directory.

     Note

     The path to a user identifier file varies based on the operating system.

     • Linux: /etc/ilogtail/users/

     • Windows: C:\LogtailData\users\

     • 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.

   Important

   After you perform the preceding operations, you must restart Logtail. For more information, see Appendix: Restart Logtail.

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

   You can use the ALIYUN_LOGTAIL_USER_DEFINED_ID environment variable or the user_defined_id file in a specified directory to check whether a custom identifier is configured for your server. If a custom identifier is configured by using the environment variable, the configuration of the environment variable takes precedence. You can run the following command to check whether the custom identifier is configured by using the environment variable:

   echo $ALIYUN_LOGTAIL_USER_DEFINED_ID

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

   • If the output is not empty but does not contain the custom identifier that you specified for the machine group, you must change the value of the environment variable to the custom identifier that you specified for the machine group or append the custom identifier to the existing value. Separate multiple custom identifiers with commas (,).

   • 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 Create a custom identifier-based machine group.

     • 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 Create a custom identifier-based machine group.

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

   Important

   After you perform the preceding operations, you must restart Logtail. For more information, see Appendix: Restart Logtail.

   What to do next

   If the error persists after troubleshooting, submit a ticket.

   Appendix: Restart Logtail

   Linux

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

   2. Run the following command:

      sudo /etc/init.d/ilogtaild restart

   Windows

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

   2. Open the Run window and enter services.msc to open the Services window.

   3. Restart the LogtailDaemon or LogtailWorker service. For Logtail V1.0.0.0 or later, restart the LogtailDaemon service. For Logtail V0.x.x.x, restart the LogtailWorker service.