Is there a way that EDS IPAddress accepts docker hostname with EDS Cluster?

[oneamitj]

Is there a way we can use docker service eg webapp_dev_webapp.1.no9rqsfuz73k026uod3hsjk83 as core.SocketAddress.Address?

Docker service name for a static cluster address defined in envoy config yaml works well and resolves fine, as cluster type is logical_dns. For dynamic Envoy config, cluster type = EDS, and each cluster has its Endpoints. If I provide normal IP Address and port for each Endpoint, it works fine.
But each of my services is hosted in docker, and there is an issue using docker's internal ipaddress which is in subnet format. My option is to use docker services' Host name, as envoy itself is in same docker network, resolving hostname should not be a problem.

I initialized Endpoint as

endpoints := make([]cache.Resource, 1)
var eps []endpoint.LbEndpoint
eps = append(eps, endpoint.LbEndpoint{Endpoint: &endpoint.Endpoint{
	Address: &core.Address{
		Address: &core.Address_SocketAddress{
			SocketAddress: &core.SocketAddress{
				Protocol: core.TCP,
				Address: "webapp_dev_webapp.1.no9rqsfuz73k026uod3hsjk83",
				ResolverName: "LOGICAL_DNS",
				PortSpecifier: &core.SocketAddress_PortValue{
					PortValue: uint32(8080),
				},
			},
		},
	},
},
})

endpoints[0] = &v2.ClusterLoadAssignment{
	ClusterName: "my_cluster",
	Endpoints: []endpoint.LocalityLbEndpoints{{
		LbEndpoints: eps,
	}},
}

var edsSource *core.ConfigSource
edsSource = &core.ConfigSource{
	ConfigSourceSpecifier: &core.ConfigSource_Ads{
		Ads: &core.AggregatedConfigSource{},
	},
}
cluster := &v2.Cluster{
	Name:          "my_cluster",
	ConnectTimeout: 5 * time.Second,
	Type:           v2.Cluster_EDS,
	EdsClusterConfig: &v2.Cluster_EdsClusterConfig{
		EdsConfig: edsSource,
	},
}

// some listener and routes too

After generating and setting snapshot with above settings, envoys updates LDS, RDS, CDS but throws error in EDS as
[warning][config] bazel-out/k8-opt/bin/source/common/config/_virtual_includes/grpc_mux_subscription_lib/common/config/grpc_mux_subscription_impl.h:70] gRPC config for type.googleapis.com/envoy.api.v2.ClusterLoadAssignment rejected: Unknown address resolver: LOGICAL_DNS. Consider setting resolver_name or setting cluster type to 'STRICT_DNS' or 'LOGICAL_DNS'.

Is docker hostname via EDS cluster not supported yet or am I missing something?

[9len]

Unfortunately, while you can set the cluster type to LOGICAL_DNS in a statically configured cluster, AFAIK there is no way to set a CDS/EDS cluster to use logical DNS. It's a hole in the API.

The way we solve this in rotor is to resolve the DNS entry within the control-plane, and hand out resolved IPs in EDS.

[oneamitj]

Below code worked for me. webapp-service is my docker service name. This way envoy resolves webapp-service to as many IPs as its replica count.

var hosts []*core.Address
dnsRefreshRate := 15 * time.Second
hosts = append(hosts, &core.Address{
	Address: &core.Address_SocketAddress{
		SocketAddress: &core.SocketAddress{
			Protocol:     core.TCP,
			Address:      "webapp-service", // webapp-service is a docker service name
			ResolverName: "STRICT_DNS",
			PortSpecifier: &core.SocketAddress_PortValue{
				PortValue: uint32(8080),
			},
		},
	},
})
cluster := &v2.Cluster{
	Name:            "my_cluster",
	ConnectTimeout:  5 * time.Second,
	Type:            v2.Cluster_STRICT_DNS,
	LbPolicy:        v2.Cluster_ROUND_ROBIN,
	Hosts:           hosts,
	DnsLookupFamily: v2.Cluster_V4_ONLY,
	DnsRefreshRate:  &dnsRefreshRate,
}

[9len]

Yes, the other way to do this is to embed the hostlist directly in the cluster response, rather than using EDS at all.

[slonka]

@9len

Unfortunately, while you can set the cluster type to LOGICAL_DNS in a statically configured cluster, AFAIK there is no way to set a CDS/EDS cluster to use logical DNS. It's a hole in the API.

Is this still the case?

[9len]

AFAIK yes, but I haven’t been involved with the project for several months.

[oneamitj]

The alternative solution I provided seems no more of use (from v1.9). As Hosts in the cluster is now deprecated by LoadAssignment of type *ClusterLoadAssignment which uses EDS Cluster. This is troublesome for me too. I am staying at v1.8, as I use Docker as host and need to resolve docker service hostname to (multiple) IP.
In hope support for LOGICAL_DNS in EDS/CDS cluster will be added.
PS: Is there anything we can do to make this support added?

[alecholmez]

Handing out resolved IPs in the server before they make it to the proxies is the best solution for this. It's a relatively trivial fix as well

[pravin-singhal]

I have been using LOGICAL_DNS with envoy container starting with --dns, run dnsmasq at at the IP which can route to different DNS servers based on domains

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[github-actions]

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[binpatel31]

is this issue resolved? can we resolve DNS name with EDS as config?

[oneamitj]

@binpatel31 I don't think we can. Though, I haven't checked the latest version.

[arttkach]

I also would like to know if this issue was addressed. Static config does work but it don't seem to be working for my dynamic config. Whenever I replace an IP with a service name, in my EDS file, I get the following error:
[warning][config] [source/common/config/filesystem_subscription_impl.cc:60] Filesystem config update rejected: malformed IP address: service. Consider setting resolver_name or setting cluster type to 'STRICT_DNS' or 'LOGICAL_DNS'.
I run envoy in a container. Any plans to address this in the near future?

[20harshal]

In the attention note of https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/endpoint/v3/endpoint_components.proto#config-endpoint-v3-endpoint
The form of host address depends on the given cluster type. For STATIC or EDS, it is expected to be a direct IP address (or something resolvable by the specified resolver in the Address). For LOGICAL or STRICT DNS, it is expected to be hostname, and will be resolved via DNS.
But its saying [2022-07-20 16:58:29.848][6194][warning][config] [external/envoy/source/common/config/filesystem_subscription_impl.cc:43] Filesystem config update rejected: Error adding/updating listener(s) tcp_1: Unknown address resolver: 8.8.8.8