Docker containers "bad gateway" 使用容器名称作为 DNS 名称时出错（使用 ip 有效）

Question

摘要：我可以使用（自定义）docker 网络将一个 docker 容器连接到另一个容器（在 docker-compose 文件中），只有IP地址。使用容器名称作为 DNS 会导致“错误的网关”错误。

我正在尝试让 Grafana（作为 docker-compose）与 Prometheus（作为 docker 容器）一起工作。我将 prometheus 容器连接到 Grafana docker compose 定义的网络。这样，只要我使用它的 IP 地址，我就可以将 prometheus 服务器用作 Grafana 的数据源。如何使用 DNS 名称使其工作？使用容器名称作为 DNS 名称会导致“错误的网关”错误。

docker-compose.yml

version: '3.4'

networks:
  k6:
  grafana:

services:
  influxdb:
    image: influxdb:1.8
    networks:
      - k6
      - grafana
    ports:
      - "8086:8086"
    environment:
      - INFLUXDB_DB=k6

  grafana:
    image: grafana/grafana:latest
    networks:
      - grafana
    ports:
      - "3000:3000"
    environment:
      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
      - GF_AUTH_ANONYMOUS_ENABLED=true
      - GF_AUTH_BASIC_ENABLED=false
    volumes:
      - ./grafana:/etc/grafana/provisioning/

  k6:
    image: loadimpact/k6:latest
    networks:
      - k6
    ports:
      - "6565:6565"
    environment:
      - K6_OUT=influxdb=http://influxdb:8086/k6
    volumes:
      - ./samples:/scripts

普罗米修斯容器命令：

docker run -d -p 9090:9090 --network k6_grafana -v C:\xy\QA\K6\prometheus.yml:/etc/prometheus/prometheus.yml prom/prometheus

docker网络检查k6_grafana

[
    {
        "Name": "k6_grafana",
        "Id": "15de38f97d93a0c697de4bfdc4fe0f441bcacde9fd43f5b9d1608908bb26c954",
        "Created": "2021-10-26T09:45:17.6385164Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.27.0.0/16",
                    "Gateway": "172.27.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "37e0a02a2c7f73b2be78623a4d239b86eb2e2a1a14e8b3416d472de2a719d701": {
                "Name": "k6_grafana_1",
                "EndpointID": "f0bf0f4844775c3fa6ce6758e2e4413ff3de40e5d6b93158e5668ebe4661f6a5",
                "MacAddress": "02:42:ac:1b:00:02",
                "IPv4Address": "172.27.0.2/16",
                "IPv6Address": ""
            },
            "6efce075e766ce581e134947ef2067d0b3ae433476c850e02768b624c672da0f": {
                "Name": "practical_lalande",
                "EndpointID": "363c42b1c5194e95d4469f7c474973ba8b21f8fe2573fb22f3fac76c5ab8a1af",
                "MacAddress": "02:42:ac:1b:00:04",
                "IPv4Address": "172.27.0.4/16",
                "IPv6Address": ""
            },
            "d075b1aa33452c38e0340e4a10997be3665377a43a961e99ecab580af22dfe02": {
                "Name": "k6_influxdb_1",
                "EndpointID": "4716f96665f4f93acd3cc087d1cad1048ee035062d950fddfe9d3e176a34bcbf",
                "MacAddress": "02:42:ac:1b:00:03",
                "IPv4Address": "172.27.0.3/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {
            "com.docker.compose.network": "grafana",
            "com.docker.compose.project": "k6",
            "com.docker.compose.version": "1.28.5"
        }
    }
]

所以用http://172.27.0.4:9090连接就可以了！但是使用 http://practical_lalande:9090 连接（或任何其他名称）是行不通的！

根据 docker 文档，这应该有效：

User-defined bridges provide automatic DNS resolution between containers.

Containers on the default bridge network can only access each other by IP addresses, unless you use the --link option, which is considered legacy. On a user-defined bridge network, containers can resolve each other by name or alias.

Answer 1

事实证明，这不适用于 docker 生成的名称。 “practical_lalande”容器名称由 docker 生成。使用“--name”选项创建具有自定义名称的容器可以解决问题。

Docker containers "bad gateway" 使用容器名称作为 DNS 名称时出错（使用 ip 有效）

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