dns resolve error!

[gbhuoo]

Kong: 0.12.1
Consul v1.0.3

kong.conf

dns_resolver = 192.168.5.232:8600

but , kong Can not be resolve normally,error info below:

logs/error.log
2018/02/10 12:20:02 [error] 31047#0: *3997 [lua] responses.lua:121: after(): failed the initial dns/balancer resolve for 'auth_center.service.consul' with: 32844, client: 10.0.0.143, server: kong, request: "GET /auth_center/v3 HTTP/1.1", host: "192.168.5.232:8083"

but, i do consul query, consul is ok:
[root@docker4-test consul]# dig @192.168.5.232 -p8600 auth_center.service.consul

; <<>> DiG 9.9.4-RedHat-9.9.4-51.el7_4.2 <<>> @192.168.5.232 -p8600 auth_center.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51595
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;auth_center.service.consul. IN A

;; ANSWER SECTION:
auth_center.service.consul. 0 IN A 192.168.5.232

;; Query time: 2 msec
;; SERVER: 192.168.5.232#8600(192.168.5.232)
;; WHEN: 六 2月 10 12:40:39 CST 2018
;; MSG SIZE rcvd: 71

[Tieske]

please apply this patch: https://github.com/Kong/kong/pull/3177/files

and then try again. It won't fix it, but will provide better insight in the error.

[gbhuoo]

thank you ,i did patch it, so i get error log :

2018/02/10 19:45:28 [error] 23237#0: *930 [lua] balancer.lua:703: execute(): [dns] 32776. Tried: (short)demo.service.consul:(na) - cache-miss
demo.service.consul:33 - cache-miss/querying/16:192.168.5.232.node.api_test.consul removed/1:192.168.5.232.node.api_test.consul removed/dereferencing SRV
(short)192.168.5.232.node.api_test.consul:(na) - cache-miss
192.168.5.232.node.api_test.consul:16 - cache-hit
, client: 192.168.5.232, server: kong, request: "GET /demo/v3 HTTP/1.1", host: "192.168.5.232:8083"
2018/02/10 19:45:28 [error] 23237#0: *930 [lua] responses.lua:121: after(): failed the initial dns/balancer resolve for 'demo.service.consul' with: 32776, client: 192.168.5.232, server: kong, request: "GET /demo/v3 HTTP/1.1", host: "192.168.5.232:8083"

I think Kong has been query and achieved the correct results: port 32776, service ：demo.service.consul , but why do it report a mistake?

dig info:
dig @127.0.1 -p8600 demo.service.consul SRV

; <<>> DiG 9.9.4-RedHat-9.9.4-51.el7_4.2 <<>> @127.0.1 -p8600 demo.service.consul SRV
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47525
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;demo.service.consul. IN SRV

;; ANSWER SECTION:
demo.service.consul. 0 IN SRV 1 1 32776 192.168.5.232.node.api_test.consul.

;; ADDITIONAL SECTION:
192.168.5.232.node.api_test.consul. 0 IN A 192.168.5.232
192.168.5.232.node.api_test.consul. 0 IN TXT "consul-network-segment="

;; Query time: 1 msec
;; SERVER: 127.0.0.1#8600(127.0.0.1)
;; WHEN: 六 2月 10 19:48:12 CST 2018
;; MSG SIZE rcvd: 154

[Tieske]

I have to try and reproduce this.

What strikes me as odd is this line from the log:

192.168.5.232.node.api_test.consul:16 - cache-hit

Which means it considered the record type TXT (int 16) as a cache hit, though it is not configured to even look for that type.

Can you try to disabled the TXT entry returned by Consul?

[Tieske]

Found the issue. The problem was indeed caused by the TXT entry, which was not properly handled by the dns client.

As a workaround you can try:

• remove the TXT entry
• set the dns_order property to SRV, A, CNAME (effectively removing the last entry)

[Tieske]

Let's keep this open until the new dns-client has been released and the Kong dependency has been updated.

[gbhuoo]

thank you very much. I adopt your suggestion that this problem has been solved