ELK 简介

ELK 是一套优秀的日志搜集、存储和查询的开源软件，广泛用于日志系统。当 OpenStack 集群达到一定规模时，日志管理和分析显得日益重要，良好统一的日志管理和分析平台有助于快速定位问题。Mirantis 的 fuel 和 HPE 的 helion 均集成了 ELK。

Logstash：日志的收集和传送
Elasticsearch：日志的存储和检索
Kibana：日志的可视化，一个很炫的 portal

采用 ELK 管理 OpenStack 的日志具有以下优点：

迅速查询全局 ERROR 级别日志
某个 API 的请求频率
通过 request ID, 可过滤出某个 API 整个流程的日志

规划与设计

部署架构

控制节点作为日志服务器，存储所有 OpenStack 及其相关日志。Logstash 部署于所有节点，收集本节点下所需收集的日志，然后以网络(node/http)方式输送给控制节点的 Elasticsearch，Kibana 作为 web portal 提供展示日志信息：

ELK

日志格式

为了提供快速直观的检索功能，对于每一条 OpenStack 日志，我们希望它能包含以下属性，用于检索和过滤：

Host: 如 controller01，compute01 等
Service Name: 如 nova-api, neutron-server 等
Module: 如 nova.filters
Log Level: 如 DEBUG, INFO, ERROR 等
Log date
Request ID: 某次请求的 Request ID

以上属性可以通过 Logstash 实现，通过提取日志的关键字段，从而获上述几种属性，并在 Elasticsearch 建立索引。

安装与配置

安装

ELK 的安装步骤非常简单，可参考 logstash-es-Kibana 安装，如遇异常，请 Google。

配置

Logstash 的配置文件有专门的一套语法，学习的成本比较高，可参考 openstack logstash config 后，再根据自身需求改写：

input {
  file {
    path => ['/var/log/nova/nova-api.log']
    tags => ['nova', 'oslofmt']
    type => "nova-api"
  }
  file {
    path => ['/var/log/nova/nova-conductor.log']
    tags => ['nova-conductor', 'oslofmt']
    type => "nova"
  }
  file {
    path => ['/var/log/nova/nova-manage.log']
    tags => ['nova-manage', 'oslofmt']
    type => "nova"
  }
  file {
    path => ['/var/log/nova/nova-scheduler.log']
    tags => ['nova-scheduler', 'oslofmt']
    type => "nova"
  }
  file {
    path => ['/var/log/nova/nova-spicehtml5proxy.log']
    tags => ['nova-spice', 'oslofmt']
    type => "nova"
  }
  file {
    path => ['/var/log/keystone/keystone-all.log']
    tags => ['keystone', 'keystonefmt']
    type => "keystone"
  }
  file {
    path => ['/var/log/keystone/keystone-manage.log']
    tags => ['keystone', 'keystonefmt']
    type => "keystone"
  }
  file {
    path => ['/var/log/glance/api.log']
    tags => ['glance', 'oslofmt']
    type => "glance-api"
  }
  file {
    path => ['/var/log/glance/registry.log']
    tags => ['glance', 'oslofmt']
    type => "glance-registry"
  }
  file {
    path => ['/var/log/glance/scrubber.log']
    tags => ['glance', 'oslofmt']
    type => "glance-scrubber"
  }
  file {
    path => ['/var/log/ceilometer/ceilometer-agent-central.log']
    tags => ['ceilometer', 'oslofmt']
    type => "ceilometer-agent-central"
  }
  file {
    path => ['/var/log/ceilometer/ceilometer-alarm-notifier.log']
    tags => ['ceilometer', 'oslofmt']
    type => "ceilometer-alarm-notifier"
  }
  file {
    path => ['/var/log/ceilometer/ceilometer-api.log']
    tags => ['ceilometer', 'oslofmt']
    type => "ceilometer-api"
  }
  file {
    path => ['/var/log/ceilometer/ceilometer-alarm-evaluator.log']
    tags => ['ceilometer', 'oslofmt']
    type => "ceilometer-alarm-evaluator"
  }
  file {
    path => ['/var/log/ceilometer/ceilometer-collector.log']
    tags => ['ceilometer', 'oslofmt']
    type => "ceilometer-collector"
  }
  file {
    path => ['/var/log/heat/heat.log']
    tags => ['heat', 'oslofmt']
    type => "heat"
  }
  file {
    path => ['/var/log/neutron/neutron-server.log']
    tags => ['neutron', 'oslofmt']
    type => "neutron-server"
  }
#  Not collecting RabbitMQ logs for the moment
#   file {
# 	path => ['/var/log/rabbitmq/rabbit@<%= @hostname %>.log']
# 	tags => ['rabbitmq', 'oslofmt']
# 	type => "rabbitmq"
#   }
  file {
    path => ['/var/log/httpd/access_log']
    tags => ['horizon']
    type => "horizon"
  }
  file {
    path => ['/var/log/httpd/error_log']
    tags => ['horizon']
    type => "horizon"
  }
  file {
    path => ['/var/log/httpd/horizon_access_log']
    tags => ['horizon']
    type => "horizon"
  }
  file {
    path => ['/var/log/httpd/horizon_error_log']
    tags => ['horizon']
    type => "horizon"
  }
}
filter {
  if "oslofmt" in [tags] {
    multiline {
      negate => true
      pattern => "^%{TIMESTAMP_ISO8601} "
      what => "previous"
    }
    multiline {
      negate => false
      pattern => "^%{TIMESTAMP_ISO8601}%{SPACE}%{NUMBER}?%{SPACE}?TRACE"
      what => "previous"
    }
    grok {
      #  Do multiline matching as the above mutliline filter may add newlines
      #  to the log messages.
      #  TODO move the LOGLEVELs into a proper grok pattern.
      match => { "message" => "(?m)^%{TIMESTAMP_ISO8601:logdate}%{SPACE}%{NUMBER:pid}?%{SPACE}?(?<loglevel>AUDIT|CRITICAL|DEBUG|INFO|TRACE|WARNING|ERROR) \[?\b%{NOTSPACE:module}\b\]?%{SPACE}?%{GREEDYDATA:logmessage}?" }
      add_field => { "received_at" => "%{@timestamp}" }
    }
  } else if "keystonefmt" in [tags] {
    grok {
      #  Do multiline matching as the above mutliline filter may add newlines
      #  to the log messages.
      #  TODO move the LOGLEVELs into a proper grok pattern.
      match => { "message" => "(?m)^%{TIMESTAMP_ISO8601:logdate}%{SPACE}%{NUMBER:pid}?%{SPACE}?(?<loglevel>AUDIT|CRITICAL|DEBUG|INFO|TRACE|WARNING|ERROR) \[?\b%{NOTSPACE:module}\b\]?%{SPACE}?%{GREEDYDATA:logmessage}?" }
      add_field => { "received_at" => "%{@timestamp}" }
    }
    if [module] == "iso8601.iso8601" {
  # log message for each part of the date?  Really?
  drop {}
    }
  } else if "libvirt" in [tags] {
    grok {
       match => { "message" => "(?m)^%{TIMESTAMP_ISO8601:logdate}:%{SPACE}%{NUMBER:code}:?%{SPACE}\[?\b%{NOTSPACE:loglevel}\b\]?%{SPACE}?:?%{SPACE}\[?\b%{NOTSPACE:module}\b\]?%{SPACE}?%{GREEDYDATA:logmessage}?" }
       add_field => { "received_at" => "%{@timestamp}"}
    }
    mutate {
       uppercase => [ "loglevel" ]
    }
  } else if [type] == "syslog" {
     grok {
        match => { "message" => "%{SYSLOGTIMESTAMP:syslog_timestamp} %{SYSLOGHOST:syslog_hostname} %{DATA:syslog_program}(?:\[%{POSINT:syslog_pid}\])?: %{GREEDYDATA:logmessage}" }
        add_field => [ "received_at", "%{@timestamp}" ]
     }
     syslog_pri {
        severity_labels => ["ERROR", "ERROR", "ERROR", "ERROR", "WARNING", "INFO", "INFO", "DEBUG" ]
     }
     date {
        match => [ "syslog_timestamp", "MMM  d HH:mm:ss", "MMM dd HH:mm:ss" ]
     }
     if !("_grokparsefailure" in [tags]) {
        mutate {
           replace => [ "@source_host", "%{syslog_hostname}" ]
        }
     }
     mutate {
        remove_field => [ "syslog_hostname", "syslog_timestamp" ]
        add_field => [ "loglevel", "%{syslog_severity}" ]
        add_field => [ "module", "%{syslog_program}" ]
     }
  }
}

output {
    elasticsearch { host => controller }
}