Log Service allows you to collect NGINX logs and analyze logs in multiple dimensions. You can create Logtail configurations to collect logs. This topic describes how to create a Logtail configuration in NGINX mode by using the Log Service console.

Prerequisites

  • A project and a Logstore are created. For more information, see Create a project and Create a Logstore.
  • The server on which Logtail is installed can connect to port 80 and port 443 of remote servers.

Procedure

  1. Log on to the Log Service console.
  2. In the Import Data section, click Nginx - Text Log.
  3. Select the project and Logstore. Then, click Next.
  4. Create a machine group.
    • If a machine group is available, click Use Existing Machine Groups.
    • If no machine groups are available, perform the following steps to create a machine group. In this example, an Elastic Compute Service (ECS) instance is used.
      1. On the ECS Instances tab, select Manually Select Instances. Then, select the ECS instance that you want to use and click Execute Now.

        For more information, see Install Logtail on ECS instances.

        Note If you want to collect logs from an ECS instance that belongs to a different Alibaba Cloud account, a server in an on-premises data center, or a server of a third-party cloud service provider, you must manually install Logtail. For more information, see Install Logtail on a Linux server or Install Logtail on a Windows server. After you manually install Logtail, you must configure a user identifier on the server. For more information, see Configure a user identifier.
      2. After Logtail is installed, click Complete Installation.
      3. In the Create Machine Group step, configure Name and click Next.

        Log Service allows you to create IP address-based machine groups and custom identifier-based machine groups. For more information, see Create an IP address-based machine group and Create a custom ID-based machine group.

  5. Select the newly created machine group and move it from the Source Server Groups section to the Applied Server Groups section. Then, click Next.
    Notice If you apply a machine group immediately after it is created, the heartbeat status of the machine group may be FAIL. This issue occurs because the machine group is not connected to Log Service. In this case, you can click Automatic Retry. If the issue persists, see What do I do if no heartbeat connections are detected on Logtail?
  6. Create a Logtail configuration and click Next.
    Collect NGINX logs
    Parameter Description
    Config Name Enter a name for the Logtail configuration. The name must be unique in a project. After the Logtail configuration is created, you cannot change the name of the Logtail configuration.

    You can click Import Other Configuration to import a Logtail configuration from another project.

    Log Path Specify the log file directory and log file name.
    You can specify an exact directory and an exact name. You can also use wildcard characters to specify the directory and name. For more information, see Wildcard matching. Log Service scans all levels of the specified directory for the log files that match specified conditions. Examples:
    • If you specify /apsara/nuwa/**/*.log, Log Service collects logs from the log files whose names are suffixed by .log in the /apsara/nuwa directory and the recursive subdirectories of the directory.
    • If you specify /var/logs/app_*/*.log, Log Service collects logs from the log files that meet the following conditions: The file name contains .log. The file is stored in a subdirectory under the /var/logs directory or in a recursive subdirectory of the subdirectory. The name of the subdirectory matches the app_* pattern.
    Note
    Blacklist If you turn on Blacklist, you must configure a blacklist to specify the directories or files that you want Log Service to skip when it collects logs. You can specify exact directories and file names. You can also use wildcards to specify directories and file names. Examples:
    • If you select Filter by Directory from a drop-down list in the Filter Type column and enter /home/admin/dir1 for Content, all files in the /home/admin/dir1 directory are skipped.
    • If you select Filter by Directory from a drop-down list in the Filter Type column and enter /home/admin/dir* for Content, the files in all subdirectories whose names are prefixed by dir in the /home/admin/ directory are skipped.
    • If you select Filter by Directory from a drop-down list in the Filter Type column and enter /home/admin/*/dir for Content, all files in dir directories in each subdirectory of the /home/admin/ directory are skipped.

      For example, the files in the /home/admin/a/dir directory are skipped, but the files in the /home/admin/a/b/dir directory are not skipped.

    • If you select Filter by File from a drop-down list in the Filter Type column and enter /home/admin/private*.log for Content, all files whose names are prefixed by private and suffixed by .log in the /home/admin/ directory are skipped.
    • If you select Filter by File from a drop-down list in the Filter Type column and enter /home/admin/private*/*_inner.log for Content, all files whose names are suffixed by _inner.log in the subdirectories whose names are prefixed by private in the /home/admin/ directory are skipped.

      For example, the /home/admin/private/app_inner.log file is skipped, but the /home/admin/private/app.log file is not skipped.

    Note
    • When you configure this parameter, you can use only asterisks (*) or question marks (?) as wildcard characters.
    • If you use wildcard characters to configure Log Path and you want to skip some directories in the specified directory, you must configure the blacklist and enter a complete directory.

      For example, if you set Log Path to /home/admin/app*/log/*.log and you want to skip all subdirectories in the /home/admin/app1* directory, you must select Filter by Directory and enter /home/admin/app1*/** to configure the blacklist. If you enter /home/admin/app1*, the blacklist does not take effect.

    • When a blacklist is in use, computational overhead is generated. We recommend that you add up to 10 entries to the blacklist.
    Docker File If you want to collect logs from Docker containers, you must turn on Docker File and specify the directories and tags of the containers. Logtail monitors the containers to check whether the containers are created or destroyed. Then, Logtail filters the logs of the containers based on tags and collects the logs that meet the filter conditions. For more information about how to collect the text logs of containers, see Use the Log Service console to collect container text logs in DaemonSet mode.
    Mode Select the log collection mode. By default, NGINX Configuration Mode is displayed. You can change the mode.
    NGINX Log Configuration Enter the log configuration section that is specified in the NGINX configuration file. The section starts with log_format. Example: 
    log_format main  '$remote_addr - $remote_user [$time_local] "$request" '
                 '$request_time $request_length '
                 '$status $body_bytes_sent "$http_referer" '
                 '"$http_user_agent"';

    For more information, see Additional information: Log formats and sample logs.

    Regular Expression Log Service generates a regular expression based on the content that you enter in NGINX Log Configuration.
    Log Sample Enter a sample NGINX log that is collected from an actual scenario. Example:
    192.168.1.2 - - [10/Jul/2020:15:51:09 +0800] "GET /ubuntu.iso HTTP/1.0" 0.000 129 404 168 "-" "Wget/1.11.4 Red Hat modified"

    Log Service uses the sample log to check whether the content of NGINX Log Configuration matches the generated regular expression. After you enter the sample log, click Verify. If the verification is successful, Log Service automatically extracts the values for NGINX Key from the sample log.

    NGINX Key The NGINX keys and values are automatically generated based on the content of NGINX Log Configuration and Log Sample.
    Drop Failed to Parse Logs
    • If you turn on Drop Failed to Parse Logs, the logs that fail to be parsed are not uploaded to Log Service.
    • If you turn off Drop Failed to Parse Logs, the logs that fail to be parsed are still uploaded to Log Service as the value of the __raw_log__ field.
    Maximum Directory Monitoring Depth Specify the maximum number of levels of subdirectories that you want to monitor. The subdirectories are in the log file directory that you specify. Valid values: 0 to 1000. The value 0 indicates that only the specified log file directory is monitored.
    You can configure advanced settings based on your business requirements. We recommend that you do not modify the advanced settings. The following table describes the parameters in the advanced settings.
    Parameter Description
    Enable Plug-in Processing If you turn on Enable Plug-in Processing, you can configure Logtail plug-ins to process logs. For more information, see Overview.
    Note If you turn on Enable Plug-in Processing, the parameters such as Upload Raw Log, Timezone, Drop Failed to Parse Logs, Filter Configuration, and Incomplete Entry Upload (Delimiter mode) become unavailable.
    Upload Raw Log If you turn on Upload Raw Log, each raw log is uploaded to Log Service as the value of the __raw__ field together with the log parsed from the raw log.
    Topic Generation Mode Select the topic generation mode. For more information, see Log topics.
    • Null - Do not generate topic: In this mode, the topic field is set to an empty string. When you query logs, you do not need to specify a topic. This is the default value.
    • Machine Group Topic Attributes: In this mode, topics are configured at the machine group level. If you want to distinguish the logs that are generated by different servers, select this mode.
    • File Path RegEx: In this mode, you must specify a regular expression in the Custom RegEx field. The part of a log path that matches the regular expression is used as the topic. If you want to distinguish the logs that are generated by different users or instances, select this mode.
    Log File Encoding Select the encoding format of log files. Valid values: utf8 and gbk.
    Timezone Select the time zone in which logs are collected. Valid values:
    • System Timezone: If you select this value, the time zone of the server or the container on which Logtail is installed is used.
    • Custom: If you select this value, you must select a time zone based on your business requirements.
    Timeout Select a timeout period of log files. If a log file is not updated within the specified period, Logtail considers the file to be timed out. Valid values:
    • Never: All log files are continuously monitored and never time out.
    • 30 Minute Timeout: If a log file is not updated within 30 minutes, Logtail considers the file to be timed out and stops monitoring the file.

      If you select 30 Minute Timeout, you must configure the Maximum Timeout Directory Depth parameter. Valid values: 1 to 3.

    Filter Configuration Specify the filter conditions that you want to use to collect logs. Only the logs that match the specified filter conditions are collected. Examples:
    • Collect the logs that match the specified filter conditions: If you set Key to level and RegEx to WARNING|ERROR, only the logs whose level is WARNING or ERROR are collected.
    • Filter out the logs that do not match the specified filter conditions. For more information, see Regular-Expressions.info.
      • If you set Key to level and RegEx to ^(?!.*(INFO|DEBUG)).*, the logs whose level contains INFO or DEBUG are not collected.
      • If you set Key to level and RegEx to ^(?!(INFO|DEBUG)$).*, the logs whose level is INFO or DEBUG are not collected.
      • If you set Key to url and RegEx to .*^(?!.*(healthcheck)).*, the logs whose url contains healthcheck are not collected. For example, if a log has the Key field of url and the Value field of /inner/healthcheck/jiankong.html, the log is not collected.

    For more information, see regex-exclude-word and regex-exclude-pattern.

    First Collection Size Specify the size of data that Logtail can collect from a log file the first time Logtail collects logs from the file. The default value of First Collection Size is 1024. Unit: KB.
    • If the file size is less than 1,024 KB, Logtail collects data from the beginning of the file.
    • If the file size is greater than 1,024 KB, Logtail collects the last 1,024 KB of data in the file.

    You can specify First Collection Size based on your business requirements. Valid values: 0 to 10485760. Unit: KB.

    More Configurations Specify extended settings for Logtail. For more information, see advanced.

    For example, if you want to use the current Logtail configuration to collect logs from log files that match a different Logtail configuration and specify the interval at which logs are aggregated and sent to Log Service, you can specify extended settings for the current Logtail. 

    {
  "force_multiconfig": true,
  "batch_send_interval": 3
}
    Click Next to complete the Logtail configuration creation. Then, Log Service starts to collect logs.
  7. Preview data, configure indexes, and then click Next.
    By default, full-text indexing is enabled for Log Service. You can also configure field indexes based on collected logs in manual or automatic mode. For more information, see Configure indexes.
    Note If you want to query and analyze logs, you must enable full-text indexing or field indexing. If you enable both full-text indexing and field indexing, the system uses only field indexes.

Additional information: Log formats and sample logs

Before you collect NGINX logs, you must configure log_format and access_log in the /etc/nginx/nginx.conf file. log_format specifies the log format, and access_log specifies the directory in which the NGINX log files are stored.

  • Log format
    In the following example, the default values of log_format and access_log are used: 
    log_format main  '$remote_addr - $remote_user [$time_local] "$request" '
                 '$request_time $request_length '
                 '$status $body_bytes_sent "$http_referer" '
                 '"$http_user_agent"';
access_log /var/logs/nginx/access.log main

    The following table describes the log fields.

    Field Description
    remote_addr The IP address of the client.
    remote_user The username that is used by the client to send a request.
    time_local The system time of the server. The value must be enclosed in brackets [].
    request The URL and HTTP protocol of a request.
    request_time The time that is required to process a request. Unit: seconds.
    request_length The length of a request. The request line, request headers, and request body are all counted.
    status The status of a request.
    body_bytes_sent The number of bytes in a response that is sent to the client. The response header is not counted.
    http_referer The URL of the source web page.
    http_user_agent The browser information of the client.
  • Sample log 
    192.168.1.2 - - [10/Jul/2020:15:51:09 +0800] "GET /ubuntu.iso HTTP/1.0" 0.000 129 404 168 "-" "Wget/1.11.4 Red Hat modified"