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syslog-ng Premium Edition 7.0.18 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng PE quick-start guide The syslog-ng PE configuration file Collecting log messages — sources and source drivers
How sources work default-network-drivers: Receive and parse common syslog messages internal: Collecting internal messages file: Collecting messages from text files wildcard-file: Collecting messages from multiple text files linux-audit: Collecting messages from Linux audit logs network: Collecting messages using the RFC3164 protocol (network() driver) office365: Fetching logs from Office 365 osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes program: Receiving messages from external applications python: writing server-style Python sources python-fetcher: writing fetcher-style Python sources snmptrap: Read Net-SNMP traps sun-streams: Collecting messages on Sun Solaris syslog: Collecting messages using the IETF syslog protocol (syslog() driver) system: Collecting the system-specific log messages of a platform systemd-journal: Collecting messages from the systemd-journal system log storage systemd-syslog: Collecting systemd messages using a socket tcp, tcp6, udp, udp6: Collecting messages from remote hosts using the BSD syslog protocol udp-balancer: Receiving UDP messages at very high rate unix-stream, unix-dgram: Collecting messages from UNIX domain sockets windowsevent: Collecting Windows event logs
Sending and storing log messages — destinations and destination drivers
elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED) elasticsearch-http: Sending messages to Elasticsearch HTTP Event Collector file: Storing messages in plain-text files hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka: Publishing messages to Apache Kafka logstore: Storing messages in encrypted files mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) pipe: Sending messages to named pipes program: Sending messages to external applications python: writing custom Python destinations smtp: Generating SMTP messages (email) from logs splunk-hec: Sending messages to Splunk HTTP Event Collector sql: Storing messages in an SQL database stackdriver: Sending logs to the Google Stackdriver cloud syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng(): Forward logs to another syslog-ng node tcp, tcp6, udp, udp6: Sending messages to a remote log server using the legacy BSD-syslog protocol (tcp(), udp() drivers) unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal — usertty() destination Client-side failover
Routing messages: log paths, flags, and filters Global options of syslog-ng PE TLS-encrypted message transfer Advanced Log Transfer Protocol Reliability and minimizing the loss of log messages Manipulating messages parser: Parse and segment structured messages Processing message content with a pattern database Correlating log messages Enriching log messages with external data Monitoring statistics and metrics of syslog-ng Multithreading and scaling in syslog-ng PE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages Glossary

stackdriver: Sending logs to the Google Stackdriver cloud

The stackdriver destination of syslog-ng PE can send log messages to the Google Stackdriver cloud. Google Stackdriver is a widely used metrics, event, and log aggregator and analyzer system. The stackdriver destination is available in syslog-ng PE version 7.0.14 and later.

How the stackdriver destination works

The stackdriver destination uses the HTTP REST API to perform OAuth2 authentication to Google Stackdriver and obtains an access token from Stackdriver using the key specified in a JSON file. This access token is required to send logs to Stackdriver using the Stackdriver Logging API.

The syslog-ng PE application automatically refreshes the token when it expires (usually every 60 minutes). The syslog-ng PE application stores the token it obtains, even if you restart or reload syslog-ng PE. If you change the JSON key on your syslog-ng PE host, syslog-ng PE will start using the new key only when the stored access token expires or becomes invalid.

By default, syslog-ng PE uses the default system CA certificate store to validate the certificate sent by Google Stackdriver. If the Certificate Authority of the certificate sent by Google Stackdriver is not available on your host, you must download the CA certificate and add it to the certificate store. The location of the certificate store depends on your platform. Most commonly, it is one of the following (or a similar location):

  • /etc/ssl/certs/

  • /etc/pki/ca-trust/

  • /etc/pki/tls/certs/

  • The log_id() option of the destination currently does not support macros or templates, only strings. As a result, every log entry has the same log id.

  • Currently the following resource types are supported: generic_node, generic_task, and global. You can configure other resource types, but they are untested.

  • Each syslog-ng PE stackdriver destination can use only one resource type. If you want to send logs using multiple resource types, you must configure multiple stackdriver destinations.

  • When referring to options in the syslog-ng PE configuration file, the hyphen (-) and underscore (_) characters are usually interchangeable. In the stackdriver destination, you must use underscore (_) in the options that syslog-ng PE passes directly to Google Stackdriver. These options are the following:

    • gcp_auth_header and its contents

    • log_id

    • project_id

    • resource() and its contents.


In order to use this destination, syslog-ng Premium Edition must run in server mode. Typically, only the central syslog-ng Premium Edition server uses this destination. For details on the server mode, see Server mode.

destination d_stackdriver {
Example: Sending log messages to Google Stackdriver

Using a generic_node resource type to send log messages to Google Stackdriver

destination d_stackdriver {
        namespace("my cluster")
Batch size

The batch-lines(), batch-lines(), and batch-timeout() options of the destination determine how many log messages syslog-ng PE sends in a batch. The batch-lines() option determines the maximum number of messages syslog-ng PE puts in a batch in. This can be limited based on size and time:

  • syslog-ng PE sends a batch every batch-timeout() milliseconds, even if the number of messages in the batch is less than batch-lines(). This ensures that the destination receives every message in a timely manner even if suddenly there are no more messages.

  • syslog-ng PE sends the batch if the total size of the messages in the batch reaches batch-bytes() bytes.

To increase the performance of the destination, increase the number of worker threads for the destination using the workers() option, or adjust the batch-bytes(), batch-lines(), batch-timeout() options.

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