request help: APISIX retuen error 3 name error with multi Consul DNS

[tzssangglass]

Discussed in #8338

^{Originally posted by Fabriceli November 16, 2022}
Version info:

• APISIX 3.0.0
• Consul 1.9.5
• Linux arch x86_64

ERROR:

[error] 43382#43382: *1626 [lua] init.lua:428: handle_upstream(): failed to set upstream: no valid upstream node: failed to query the DNS server: dns server error: 3 name error, client: a.a.a.a, server: _, request: "GET /api/v0/test/ HTTP/1.1", host: "b.b.b.b"

with /usr/local/apisix/conf/config.yaml:

discovery:
  dns:
    servers:
      - "x.x.x.x:8600" 
      - "y.y.y.y:8600"

service A is only valid in Consul y.y.y.y:8600. APISIX is not support multi Consul DNS?

[tzssangglass]

hi @Fabriceli , I eventually tracked it down here: https://github.com/openresty/lua-resty-dns/blob/master/lib/resty/dns/resolver.lua#L870-L896

            for _ = 1, 128 do
                buf, err = sock:receive(4096)
                if err then
                    local server = _get_cur_server(self)
                    err = "failed to receive reply from UDP server "
                        .. concat(server, ":") .. ": " .. err
                    break
                end


                if buf then
                    local answers
                    answers, err = parse_response(buf, id, opts)
                    if err == "truncated" then
                        answers, err = _tcp_query(self, query, id, opts)
                    end


                    if err and err ~= "id mismatch" then
                        break
                    end


                    if answers then
                        return answers, nil, tries
                    end
                end
                -- only here in case of an "id mismatch"
            end
        end

1. first query "service-name-x.service.dc-name-x.consul" from x.x.x.x:8600
2. then get the buf, and err is nil, so it won't go into if err then, just parse_response(buf, id, opts) and the answers is

{
  errcode = 3,
  errstr = "name error"
}

3. and then return this error directly, won't try to query on y.y.y.y:8600 again.

or multi DNS, APISIX is not work like this ??:

in your scenario, yes

[Fabriceli]

How to fix it ?

[tzssangglass]

How to fix it ?

I don't think it needs to be fixed. I think this is a new feature. I don't have any good ideas to implement it at the moment.

[Fabriceli]

When can add this new feature? or make a discussion about this feature at next Community Weekly Meeting

[tokers]

@tzssangglass I think a good way to support this is to let users define multiple DNS service registries, and for each registry, one can define a group of DNS servers, which are the same for the domain resolving. While for different DNS service registries, the resolve result might be different.

[tzssangglass]

I think a good way to support this is to let users define multiple DNS service registries, and for each registry, one can define a group of DNS servers, which are the same for the domain resolving. While for different DNS service registries, the resolve result might be different.

I think on a high level, this requires APISIX discovery mode to support multiple clusters and orchestrate query rules.

[tzssangglass]

When can add this new feature? or make a discussion about this feature at next Community Weekly Meeting

Yes, if there is a community meeting in the near future, we will let you know in the discussion and on the mailing list.

[tokers]

I think a good way to support this is to let users define multiple DNS service registries, and for each registry, one can define a group of DNS servers, which are the same for the domain resolving. While for different DNS service registries, the resolve result might be different.

I think on a high level, this requires APISIX discovery mode to support multiple clusters and orchestrate query rules.

Right.

[Fabriceli]

@tokers
for this feature, I create a Consul register not Consul with kv, May I create a PR to merger in master? for help other guys

[tokers]

@tokers for this feature, I create a Consul register not Consul with kv, May I create a PR to merger in master? for help other guys

That's cool. Welcome to submit PR!

[Fabriceli]

@tokers please assign it to me

[tokers]

@tokers please assign it to me

We can create another issue to track the new consul service discovery.

[Fabriceli]

@tokers please assign it to me

We can create another issue to track the new consul service discovery.

I created #8371, Could you assign this feature to me?

[shreemaan-abhishek]

closing this as completed by #8380