无法通过服务名访问docker-swarm容器

Question

我不能从docker swarm的同一覆盖网络上的另一个容器中通过它的服务名称来ping服务。我的步骤是：

# docker swarm init
# docker network create -d overlay --attachable net1
# docker service create --name dns1 --network net1 tutum/dnsutils sleep 3000
# docker service create --name dns2 --network net1 tutum/dnsutils sleep 3000

这创建了1节点群、用户定义的覆盖网络和2个服务。我应该能够执行到一个容器中，并通过服务名ping另一个容器，但它不起作用：

# docker exec -it dns1.1.6rned8409m9jkqoxgutzjz4y4 /bin/bash
root@05cba6fd8a0b:/# ping dns2
PING dns2 (10.0.5.5) 56(84) bytes of data.
From 05cba6fd8a0b (10.0.5.3) icmp_seq=1 Destination Host Unreachable
From 05cba6fd8a0b (10.0.5.3) icmp_seq=2 Destination Host Unreachable
From 05cba6fd8a0b (10.0.5.3) icmp_seq=3 Destination Host Unreachable
^C
--- dns2 ping statistics ---
4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3062ms

我可以通过全主机名(dns2.1.idkledfjgd5dwkv6piywpfk)或IP (10.0.5.6)直接ping容器。

环境信息：

# docker network inspect -v net1
[
    {
        "Name": "net1",
        "Id": "ngzwl7l7m0zb5brvee21mvfcz",
        "Created": "2020-12-14T22:05:25.962132239Z",
        "Scope": "swarm",
        "Driver": "overlay",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "10.0.5.0/24",
                    "Gateway": "10.0.5.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "05cba6fd8a0bc4e480b50f91fb395d27ee4998277d480109cb95249c38852909": {
                "Name": "dns1.1.6rned8409m9jkqoxgutzjz4y4",
                "EndpointID": "6bcc76c8688527fcf26d2ed313e351a54b8de69d28cde4388032849a2ff91a3e",
                "MacAddress": "02:42:0a:00:05:03",
                "IPv4Address": "10.0.5.3/24",
                "IPv6Address": ""
            },
            "c1d9252f528b177ac397b7b9bf627996993ddc0f54aad3ee3862d93dcac407a3": {
                "Name": "dns2.1.idkledfjgd5dwknv6pirywpfk",
                "EndpointID": "fafd8335715737c26c83ff8a3e7c52a302eb48cbb6b7bb75e396ed6a483bfd31",
                "MacAddress": "02:42:0a:00:05:06",
                "IPv4Address": "10.0.5.6/24",
                "IPv6Address": ""
            },
            "lb-net1": {
                "Name": "net1-endpoint",
                "EndpointID": "09e3b875528a05dc39a910b8cfe5cfd57756681c4aeffd56a0c9fb41d6bffd23",
                "MacAddress": "02:42:0a:00:05:04",
                "IPv4Address": "10.0.5.4/24",
                "IPv6Address": ""
            }
        },
        "Options": {
            "com.docker.network.driver.overlay.vxlanid_list": "4101"
        },
        "Labels": {},
        "Peers": [
            {
                "Name": "4dc98c7e5f08",
                "IP": "192.168.1.26"
            }
        ],
        "Services": {
            "dns1": {
                "VIP": "10.0.5.2",
                "Ports": [],
                "LocalLBIndex": 269,
                "Tasks": [
                    {
                        "Name": "dns1.1.6rned8409m9jkqoxgutzjz4y4",
                        "EndpointID": "6bcc76c8688527fcf26d2ed313e351a54b8de69d28cde4388032849a2ff91a3e",
                        "EndpointIP": "10.0.5.3",
                        "Info": {
                            "Host IP": "192.168.1.26"
                        }
                    }
                ]
            },
            "dns2": {
                "VIP": "10.0.5.5",
                "Ports": [],
                "LocalLBIndex": 270,
                "Tasks": [
                    {
                        "Name": "dns2.1.idkledfjgd5dwknv6pirywpfk",
                        "EndpointID": "fafd8335715737c26c83ff8a3e7c52a302eb48cbb6b7bb75e396ed6a483bfd31",
                        "EndpointIP": "10.0.5.6",
                        "Info": {
                            "Host IP": "192.168.1.26"
                        }
                    }
                ]
            }
        }
    }
]

和

# docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Build with BuildKit (Docker Inc., v0.4.2-docker)

Server:
 Containers: 3
  Running: 2
  Paused: 0
  Stopped: 1
 Images: 7
 Server Version: 20.10.0
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: active
  NodeID: x2o135d3kkfxw6lb6mfyx8s3h
  Is Manager: true
  ClusterID: v5x80quwm3vwsubwdd6pclj4r
  Managers: 1
  Nodes: 1
  Default Address Pool: 10.0.0.0/8  
  SubnetSize: 24
  Data Path Port: 4789
  Orchestration:
   Task History Retention Limit: 5
  Raft:
   Snapshot Interval: 10000
   Number of Old Snapshots to Retain: 0
   Heartbeat Tick: 1
   Election Tick: 10
  Dispatcher:
   Heartbeat Period: 5 seconds
  CA Configuration:
   Expiry Duration: 3 months
   Force Rotate: 0
  Autolock Managers: false
  Root Rotation In Progress: false
  Node Address: 192.168.1.26
  Manager Addresses:
   192.168.1.26:2377
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 269548fa27e0089a8b8278fc4fc781d7f65a939b
 runc version: ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: default
 Kernel Version: 5.4.73-1-pve
 Operating System: Ubuntu 20.10
 OSType: linux
 Architecture: x86_64
 CPUs: 6
 Total Memory: 15.62GiB
 Name: dockerHost
 ID: CCGD:MQRE:PGJJ:YRU5:M4IM:5INT:EGA5:IER3:22UL:7CI3:PZOU:EZZ2
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No blkio weight support
WARNING: No blkio weight_device support

Answer 1

对于任何想要在未来看到这个的人。对我来说，问题是我在proxmox (ubuntu 20.04模板)上的LXC容器中运行docker。我在ubuntu 20.04虚拟机上测试了它，它完全按照预期工作。我不知道问题到底是什么，也不知道它是否可以修复，但基本上在LXC容器中运行它是不会起作用的。