CoreDNS not recognizing queries with unempty "text" keys in etcd records

Question

I've spent my last 2 days trying to figure out what's wrong with my setup and couldn't find a resonable answer or solution, so I want to share it with you.

What happened: I've deployed a new etcd using helm and configured external-dns to create dns records inside it, and also set-up a coredns deployment to read records from etcd.

but, the problem is, when the records are created inside etcd, coredns wouldn't response to my dig commands, in short, i think coredns doesn't recognize queries with unempty "text" keys.

external-dns creates these items:

/opt/bitnami/etcd$ etcdctl get --prefix '/skydns'

/skydns/com/aminm/cname-goh/3ee06812
{"text":"\"heritage=external-dns,external-dns/owner=staging,external-dns/resource=ingress/stg-infra/goh.aminm.com-k8s\"","targetstrip":1}
/skydns/com/aminm/goh/149a1668
{"host":"sag.com","text":"\"heritage=external-dns,external-dns/owner=staging,external-dns/resource=ingress/stg-infra/goh.aminm.com-k8s\"","targetstrip":1}

and dnstools returns no result:

dnstools# dig @10.103.49.243 goh.aminm.com

; <<>> DiG 9.11.3 <<>> @10.103.49.243 goh.aminm.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52879
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: f75cd784c97c1fd1 (echoed)
;; QUESTION SECTION:
;goh.aminm.com.                 IN      A

;; AUTHORITY SECTION:
aminm.com.              30      IN      SOA     ns.dns.aminm.com. hostmaster.aminm.com. 1684880221 7200 1800 86400 30

;; Query time: 9 msec
;; SERVER: 10.103.49.243#53(10.103.49.243)
;; WHEN: Tue May 23 22:17:01 UTC 2023
;; MSG SIZE  rcvd: 135

coredns log:

[INFO] 10.35.0.21:48154 - 29227 "A IN goh.aminm.com. udp 54 false 4096" NOERROR qr,aa,rd 112 0.002888737s

but when i manually create a new record and specify no "text" value in etcd:

/opt/bitnami/etcd$ etcdctl put /skydns/com/aminm/goh/3031e6b8 '{"host":"sag.com","text":"","targetstrip":1}'

dig command works correctly:

dnstools# dig @10.103.49.243 goh.aminm.com

; <<>> DiG 9.11.3 <<>> @10.103.49.243 goh.aminm.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47171
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;goh.aminm.com.                 IN      A

;; ANSWER SECTION:
goh.aminm.com.          1296000 IN      A       66.94.118.137

;; Query time: 242 msec
;; SERVER: 10.103.49.243#53(10.103.49.243)
;; WHEN: Tue May 23 22:23:40 UTC 2023
;; MSG SIZE  rcvd: 71

also this is my coredns configuration:

.:53 {
    kubernetes cluster.local in-addr.arpa ip6.arpa {
        pods insecure
        fallthrough
        ttl 30
    }
    etcd aminm.com {
        path /skydns
        endpoint http://dns-etcd.stg-infra.svc.cluster.local:2379
        fallthrough
    }
    errors
    health {
        lameduck 5s
    }
    ready
    log
    prometheus 0.0.0.0:9153
    forward . 1.1.1.1
    reload
}

I expect coredns to be able to read and response to etcd keys even if they have "test" key inside them

CoreDNS not recognizing queries with unempty "text" keys in etcd records

0 Answers0