docker内服务访问宿主机服务

1. 场景
2. 解决
4. 参考

1. 场景

使用windows， wsl2 进行日常开发测试工作。但是wsl2经常会遇到网络问题。比如今天在测试一个项目，核心功能是将postgres 的数据使用开源组件synch 同步到clickhouse 这个工作。

测试所需组件

postgres
kafka
zookeeper
redis
synch容器

最开始测试时，选择的方案是，将上述五个服务使用 docker-compose 进行编排， network_modules使用hosts模式，因为考虑到kafka的监听安全机制，这种网络模式，无需单独指定暴露端口。

docker-compose.yaml 文件如下

version: "3"

services:

  postgres:

    image: failymao/postgres:12.7

    container_name: postgres

    restart: unless-stopped

    privileged: true                                                      # 设置docker-compose env 文件

    command: [ "-c", "config_file=/var/lib/postgresql/postgresql.conf", "-c", "hba_file=/var/lib/postgresql/pg_hba.conf" ]

    volumes:

      - ./config/postgresql.conf:/var/lib/postgresql/postgresql.conf

      - ./config/pg_hba.conf:/var/lib/postgresql/pg_hba.conf

    environment:

      POSTGRES_PASSWORD: abc123

      POSTGRES_USER: postgres

      POSTGRES_PORT: 15432

      POSTGRES_HOST: 127.0.0.1

    healthcheck:

      test: sh -c "sleep 5 && PGPASSWORD=abc123 psql -h 127.0.0.1 -U postgres -p 15432 -c '\q';"

      interval: 30s

      timeout: 10s

      retries: 3

    network_mode: "host"

  zookeeper:

    image: failymao/zookeeper:1.4.0

    container_name: zookeeper

    restart: always

    network_mode: "host"

  kafka:

    image: failymao/kafka:1.4.0

    container_name: kafka

    restart: always

    depends_on:

      - zookeeper

    environment:

      KAFKA_ADVERTISED_HOST_NAME: kafka

      KAFKA_ZOOKEEPER_CONNECT: localhost:2181

      KAFKA_LISTENERS: PLAINTEXT://127.0.0.1:9092

      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://127.0.0.1:9092

      KAFKA_BROKER_ID: 1

      KAFKA_LOG_RETENTION_HOURS: 24

      KAFKA_LOG_DIRS: /data/kafka-data  #数据挂载

    network_mode: "host"

  producer:

    depends_on:

      - redis

      - kafka

      - zookeeper

    image: long2ice/synch

    container_name: producer

    command: sh -c "

      sleep 30 &&

      synch --alias pg2ch_test produce"

    volumes:

      - ./synch.yaml:/synch/synch.yaml

    network_mode: "host"

  # 一个消费者消费一个数据库

  consumer:

    tty: true

    depends_on:

      - redis

      - kafka

      - zookeeper

    image: long2ice/synch

    container_name: consumer

    command: sh -c

      "sleep 30 &&

      synch --alias pg2ch_test consume --schema pg2ch_test"

    volumes:

      - ./synch.yaml:/synch/synch.yaml

    network_mode: "host"

  redis:

    hostname: redis

    container_name: redis

    image: redis:latest

    volumes:

      - redis:/data

    network_mode: "host"

volumes:

  redis:

  kafka:

  zookeeper:

测试过程中因为要使用 postgres, wal2json组件,在容器里单独安装组件很麻烦，尝试了几次均已失败而告终，所以后来选择了将 postgres 服务安装在宿主机上，容器里面的synch服务使用宿主机的 ip,port端口。

但是当重新启动服务后，synch服务一直启动不起来，日志显示 postgres 无法连接. synch配置文件如下

core:

  debug: true # when set True, will display sql information.

  insert_num: 20000 # how many num to submit,recommend set 20000 when production

  insert_interval: 60 # how many seconds to submit,recommend set 60 when production

  # enable this will auto create database `synch` in ClickHouse and insert monitor data

  monitoring: true

redis:

  host: redis

  port: 6379

  db: 0

  password:

  prefix: synch

  sentinel: false # enable redis sentinel

  sentinel_hosts: # redis sentinel hosts

    - 127.0.0.1:5000

  sentinel_master: master

  queue_max_len: 200000 # stream max len, will delete redundant ones with FIFO

source_dbs:

  - db_type: postgres

    alias: pg2ch_test

    broker_type: kafka # current support redis and kafka

    host: 127.0.0.1

    port: 5433

    user: postgres

    password: abc123

    databases:

      - database: pg2ch_test

        auto_create: true

        tables:

          - table: pgbench_accounts

            auto_full_etl: true

            clickhouse_engine: CollapsingMergeTree

            sign_column: sign

            version_column:

            partition_by:

            settings:

clickhouse:

  # shard hosts when cluster, will insert by random

  hosts:

    - 127.0.0.1:9000

  user: default

  password: ''

  cluster_name:  # enable cluster mode when not empty, and hosts must be more than one if enable.

  distributed_suffix: _all # distributed tables suffix, available in cluster

kafka:

  servers:

    - 127.0.0.1:9092

  topic_prefix: synch

core:

  debug: true # when set True, will display sql information.

  insert_num: 20000 # how many num to submit,recommend set 20000 when production

  insert_interval: 60 # how many seconds to submit,recommend set 60 when production

  # enable this will auto create database `synch` in ClickHouse and insert monitor data

  monitoring: true

redis:

  host: redis

  port: 6379

  db: 0

  password:

  prefix: synch

  sentinel: false # enable redis sentinel

  sentinel_hosts: # redis sentinel hosts

    - 127.0.0.1:5000

  sentinel_master: master

  queue_max_len: 200000 # stream max len, will delete redundant ones with FIFO

source_dbs:

  - db_type: postgres

    alias: pg2ch_test

    broker_type: kafka # current support redis and kafka

    host: 127.0.0.1

    port: 5433

    user: postgres

    password: abc123

    databases:

      - database: pg2ch_test

        auto_create: true

        tables:

          - table: pgbench_accounts

            auto_full_etl: true

            clickhouse_engine: CollapsingMergeTree

            sign_column: sign

            version_column:

            partition_by:

            settings:

clickhouse:

  # shard hosts when cluster, will insert by random

  hosts:

    - 127.0.0.1:9000

  user: default

  password: ''

  cluster_name:  # enable cluster mode when not empty, and hosts must be more than one if enable.

  distributed_suffix: _all # distributed tables suffix, available in cluster

kafka:

  servers:

    - 127.0.0.1:9092

  topic_prefix: synch

这种情况很奇怪，首先确认 postgres, 启动，且监听端口(此处是5433) 也正常，使用localhost和主机eth0网卡地址均报错。

2. 解决

google 答案，参考 stackoverflow 高赞回答，问题解决，原答案如下

If you are using Docker-for-mac or Docker-for-Windows 18.03+, just connect to your mysql service using the host host.docker.internal (instead of the 127.0.0.1 in your connection string).

If you are using Docker-for-Linux 20.10.0+, you can also use the host host.docker.internal if you started your Docker

container with the --add-host host.docker.internal:host-gateway option.

Otherwise, read below

Use** --network="host" **in your docker run command, then 127.0.0.1 in your docker container will point to your docker host.

更多详情见源贴

host 模式下容器内服务访问宿主机服务

将postgres监听地址修改如下 host.docker.internal 报错解决。查看宿主机 /etc/hosts 文件如下



root@failymao-NC:/mnt/d/pythonProject/pg_2_ch_demo# cat /etc/hosts

# This file was automatically generated by WSL. To stop automatic generation of this file, add the following entry to /etc/wsl.conf:

# [network]

# generateHosts = false

127.0.0.1       localhost

10.111.130.24    host.docker.internal

可以看到，宿主机 ip跟域名的映射. 通过访问域名，解析到宿主机ip, 访问宿主机服务。

最终启动 synch 服务配置如下

core:

  debug: true # when set True, will display sql information.

  insert_num: 20000 # how many num to submit,recommend set 20000 when production

  insert_interval: 60 # how many seconds to submit,recommend set 60 when production

  # enable this will auto create database `synch` in ClickHouse and insert monitor data

  monitoring: true

redis:

  host: redis

  port: 6379

  db: 0

  password:

  prefix: synch

  sentinel: false # enable redis sentinel

  sentinel_hosts: # redis sentinel hosts

    - 127.0.0.1:5000

  sentinel_master: master

  queue_max_len: 200000 # stream max len, will delete redundant ones with FIFO

source_dbs:

  - db_type: postgres

    alias: pg2ch_test

    broker_type: kafka # current support redis and kafka

    host: host.docker.internal

    port: 5433

    user: postgres

    password: abc123

    databases:

      - database: pg2ch_test

        auto_create: true

        tables:

          - table: pgbench_accounts

            auto_full_etl: true

            clickhouse_engine: CollapsingMergeTree

            sign_column: sign

            version_column:

            partition_by:

            settings:

clickhouse:

  # shard hosts when cluster, will insert by random

  hosts:

    - 127.0.0.1:9000

  user: default

  password: ''

  cluster_name:  # enable cluster mode when not empty, and hosts must be more than one if enable.

  distributed_suffix: _all # distributed tables suffix, available in cluster

kafka:

  servers:

    - 127.0.0.1:9092

  topic_prefix: synch    host: host.docker.internal

core:

  debug: true # when set True, will display sql information.

  insert_num: 20000 # how many num to submit,recommend set 20000 when production

  insert_interval: 60 # how many seconds to submit,recommend set 60 when production

  # enable this will auto create database `synch` in ClickHouse and insert monitor data

  monitoring: true

redis:

  host: redis

  port: 6379

  db: 0

  password:

  prefix: synch

  sentinel: false # enable redis sentinel

  sentinel_hosts: # redis sentinel hosts

    - 127.0.0.1:5000

  sentinel_master: master

  queue_max_len: 200000 # stream max len, will delete redundant ones with FIFO

source_dbs:

  - db_type: postgres

    alias: pg2ch_test

    broker_type: kafka # current support redis and kafka

    host:

    port: 5433

    user: postgres

    password: abc123

    databases:

      - database: pg2ch_test

        auto_create: true

        tables:

          - table: pgbench_accounts

            auto_full_etl: true

            clickhouse_engine: CollapsingMergeTree

            sign_column: sign

            version_column:

            partition_by:

            settings:

clickhouse:

  # shard hosts when cluster, will insert by random

  hosts:

    - 127.0.0.1:9000

  user: default

  password: ''

  cluster_name:  # enable cluster mode when not empty, and hosts must be more than one if enable.

  distributed_suffix: _all # distributed tables suffix, available in cluster

kafka:

  servers:

    - 127.0.0.1:9092

  topic_prefix: synch

## 3. 总结
1. 以--networks="host" 模式下启动容器时，如果想在容器内访问宿主机上的服务，将ip修改为`host.docker.internal`

4. 参考

https://stackoverflow.com/questions/24319662/from-inside-of-a-docker-container-how-do-i-connect-to-the-localhost-of-the-mach