Beats - Beats is the platform for single-purpose data shippers that is installed as lightweight agents and send data to machines to Logstash or Elasticsearch.
logstash - logstash is a tool for managing events and logs.
Riemann - Container Monitoring
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...