Docker Compose with PostgreSQL 和 Prometheus PostgreSQL Exporter 拒绝连接？

Question

我正在尝试解决这个关于 PostgreSQL 导出器到 Prometheus 的问题（https://github.com/wrouesnel/postgres_exporter), Prometheus PostgreSQL server exporter example not working on MacOS?、运行 postgres 和 postgres_exporter 容器连接到用户定义的桥网络而不是主机网络，这似乎不适用于 Mac 的 Docker 桌面。我创建了以下 docker-compose.yml:

version: "3"
services:
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: mypassword
    networks:
      - mynetwork

  exporter:
    image: wrouesnel/postgres_exporter
    environment:
      DATA_SOURCE_NAME: "postgresql://postgres:mypassword@db:5432/postgres?sslmode=disable"
    ports:
      - "9187:9187"
    networks:
      - mynetwork

networks:
  mynetwork:

不过，我对此有两个问题。首先，来自 exporter 服务的日志显示一条错误消息：

"Error opening connection to database (postgresql://postgres:PASSWORD_REMOVED@db:5432/postgres?sslmode=disable): dial tcp 172.18.0.2:5432: connect: connection refused"

这是完整的输出：

> docker-compose up
Creating network "postgres-performance-testing_mynetwork" with the default driver
Creating postgres-performance-testing_db_1       ... done
Creating postgres-performance-testing_exporter_1 ... done
Attaching to postgres-performance-testing_db_1, postgres-performance-testing_exporter_1
exporter_1  | time="2019-10-03T20:16:56Z" level=info msg="Established new database connection to \"db:5432\"." source="postgres_exporter.go:778"
exporter_1  | time="2019-10-03T20:16:56Z" level=error msg="Error opening connection to database (postgresql://postgres:PASSWORD_REMOVED@db:5432/postgres?sslmode=disable): dial tcp 172.18.0.2:5432: connect: connection refused" source="postgres_exporter.go:1348"
exporter_1  | time="2019-10-03T20:16:56Z" level=info msg="Starting Server: :9187" source="postgres_exporter.go:1459"
db_1        | The files belonging to this database system will be owned by user "postgres".
db_1        | This user must also own the server process.
db_1        | 
db_1        | The database cluster will be initialized with locale "en_US.utf8".
db_1        | The default database encoding has accordingly been set to "UTF8".
db_1        | The default text search configuration will be set to "english".
db_1        | 
db_1        | Data page checksums are disabled.
db_1        | 
db_1        | fixing permissions on existing directory /var/lib/postgresql/data ... ok
db_1        | creating subdirectories ... ok
db_1        | selecting default max_connections ... 100
db_1        | selecting default shared_buffers ... 128MB
db_1        | selecting default timezone ... Etc/UTC
db_1        | selecting dynamic shared memory implementation ... posix
db_1        | creating configuration files ... ok
db_1        | running bootstrap script ... ok
db_1        | performing post-bootstrap initialization ... ok
db_1        | syncing data to disk ... ok
db_1        | 
db_1        | Success. You can now start the database server using:
db_1        | 
db_1        |     pg_ctl -D /var/lib/postgresql/data -l logfile start
db_1        | 
db_1        | 
db_1        | WARNING: enabling "trust" authentication for local connections
db_1        | You can change this by editing pg_hba.conf or using the option -A, or
db_1        | --auth-local and --auth-host, the next time you run initdb.
db_1        | waiting for server to start....2019-10-03 20:16:57.084 UTC [42] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1        | 2019-10-03 20:16:57.095 UTC [43] LOG:  database system was shut down at 2019-10-03 20:16:56 UTC
db_1        | 2019-10-03 20:16:57.101 UTC [42] LOG:  database system is ready to accept connections
db_1        |  done
db_1        | server started
db_1        | 
db_1        | /usr/local/bin/docker-entrypoint.sh: ignoring /docker-entrypoint-initdb.d/*
db_1        | 
db_1        | waiting for server to shut down...2019-10-03 20:16:57.180 UTC [42] LOG:  received fast shutdown request
db_1        | .2019-10-03 20:16:57.182 UTC [42] LOG:  aborting any active transactions
db_1        | 2019-10-03 20:16:57.186 UTC [42] LOG:  background worker "logical replication launcher" (PID 49) exited with exit code 1
db_1        | 2019-10-03 20:16:57.186 UTC [44] LOG:  shutting down
db_1        | 2019-10-03 20:16:57.197 UTC [42] LOG:  database system is shut down
db_1        |  done
db_1        | server stopped
db_1        | 
db_1        | PostgreSQL init process complete; ready for start up.
db_1        | 
db_1        | 2019-10-03 20:16:57.297 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
db_1        | 2019-10-03 20:16:57.297 UTC [1] LOG:  listening on IPv6 address "::", port 5432
db_1        | 2019-10-03 20:16:57.299 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1        | 2019-10-03 20:16:57.310 UTC [51] LOG:  database system was shut down at 2019-10-03 20:16:57 UTC
db_1        | 2019-10-03 20:16:57.314 UTC [1] LOG:  database system is ready to accept connections

这是因为 Prometheus 导出器在准备好接受连接之前尝试连接到数据库吗？（从日志记录的顺序来看似乎就是这种情况）。

另一个问题是，如果我浏览到 localhost:9187，结果是我下载了一个包含 HTML 的文件，而不是实际看到 link 到 /metrics我可以关注：

知道如何解决这些问题吗？

Answer 1

在不知道您的图像是如何构建的情况下，我发现有两个可能的罪魁祸首需要解决：

似乎 exporter 容器首先启动，并试图在 postgres 甚至运行之前连接到 db 容器。您可能需要在 exporter 部分添加 depends_on: db。
您可能需要在 db 容器上编辑 pg_hba.conf，然后 exporter 才能连接到它。默认情况下，只允许本地连接，所以你必须附加 exporter 的 IP 地址（或者使用 /0 网络掩码，如果这是一个仅限开发的环境）

如果您解决了这两个问题，应该开始为您工作。

披露：我是一名 EnterpriseDB (EDB) 员工

Answer 2

postgres-exporter:
    image: wrouesnel/postgres_exporter:v0.8.0
    restart: always
    environment:
      #- DATA_SOURCE_NAME=postgresql://postgres:password@postgres-db:5432/postgres?sslmode=disable
      - DATA_SOURCE_URI=postgres-db:5432/postgres?sslmode=disable
      - DATA_SOURCE_USER=postgres
      - DATA_SOURCE_PASS=password
    ports:
      - "9187:9187"
    networks:
      - postgres-prometheus
    depends_on:
      - postgres-db

请注意，在此示例中，DATA_SOURCE_NAME 的值没有双引号，DATA_SOURCE_URI 的值（如果这是您的偏好）没有 "postgresql://"。它直接从主机名开始。

Docker Compose with PostgreSQL 和 Prometheus PostgreSQL Exporter 拒绝连接？

Docker Compose with PostgreSQL and Prometheus PostgreSQL Exporter refusing to connect?

postgresql

docker

docker-compose

prometheus