【问题标题】：Export custom collectd PostgreSQL metrics to GCP Stackdriver Monitoring将自定义收集的 PostgreSQL 指标导出到 GCP Stackdriver Monitoring
【发布时间】：2017-05-24 06:22:58
【问题描述】：

背景

我正在尝试通过添加自定义 <Query> 来导出 PostgreSQL 复制延迟对我的 PostgreSQL 配置的声明（来自Stackdriver PostgreSQL Plugin 的原始配置） stackdriver-agents collectd 配置目录。

/opt/stackdriver/collectd/etc/postgresql.conf:

# This is the monitoring configuration for PostgreSQL.
# Make sure the statistics collector is enabled in your PostgreSQL configuration.
# NOTE: This configuration needs to be hand-edited in order to work.
# Look for DATABASE_NAME, STATS_USER, STATS_PASS, POSTGRESQL_HOST and POSTGRESQL_PORT to adjust your configuration file.
LoadPlugin postgresql
<Plugin "postgresql">

    <Query replication_lag_seconds>
        Statement "SELECT (CASE WHEN pg_last_xlog_receive_location() = pg_last_xlog_replay_location() THEN 0 ELSE EXTRACT (EPOCH FROM now() - pg_last_xact_replay_timestamp()) END) AS log_delay"
        <Result>
            Type "gauge"
            ValuesFrom "log_delay"
        </Result>
    </Query>

    # Each database needs a separate Database section.
    # Replace DATABASE_NAME in the Database section with the name of the database.
    <Database "THE_DATABASE">
        # Host and port are only used for TCP/IP connections.
        # Leaving them out indicates you wish to connect via domain sockets.
        # When using non-standard PostgreSQL configurations, replace the below with
        Host "localhost"
        Port "5432"
        User "THE_USER"
        Password "hunter2"
        Query backends
        Query transactions
        Query queries
        Query table_states
        Query disk_io
        Query disk_usage
        Query replication_lag_seconds  # My custom query
    </Database>
</Plugin>

stackdriver-agent 日志确认插件已加载并且插件能够连接到 PostgreSQL 服务器。

collectd[30418]: plugin_load: plugin "postgresql" successfully loaded.
collectd[13849]: Successfully connected to database THE_DATABASE (user THE_USER) at server localhost:5432 (server version: 9.4.12, protocol version: 3, pid: 13862)

到这个时候，我希望看到我的“log_delay”指标显示在查看“实例 (GCE)”的指标时的 Stackdriver 监控资源。我可以看到其他 PostgreSQL 指标已经通过，更多具体来说：

我似乎也找不到任何其他默认 Query [...] 指标继承自default PostgreSQL collectd configuration 被Stackdriver PostgreSQL Plugin Documentation引用：

# [...]
LoadPlugin postgresql
<Plugin "postgresql">
    # [...]
    <Database "DATABASE_NAME">
        # [...]
        User "STATS_USER"
        Password "STATS_PASS"
        Query backends
        Query transactions
        Query queries
        Query table_states
        Query disk_io
        Query disk_usage
    </Database>
</Plugin>

问题

如何让我收集的自定义 replication_lag_seconds 指标显示在 Stackdriver Monitoring 中？
是否需要配置Custom Metrics才能获得要在 Stackdriver Monitoring 中显示的指标？

【问题讨论】：

标签： stackdriver collectd google-cloud-stackdriver

【解决方案1】：

Stackdriver 监控代理会为每个 supported third-party application 发送一个 set of curated metrics。该集合不能由用户扩展 - 任何不是精选指标都将被 API 忽略，并且必须通过 custom metrics 机制发送。

【讨论】：