Lab 9.3 - Working with CoreDNS - Discussion

deepakgcp

Got an error like below

I dont get what I did wrong..

deepakgcp

It seem like the documentation is wrong..

serewicz

You named the POD nettool, the container is named ubuntu. Try the command with nettool instead.

Could be a typo. I'll take a look and fix the material if so.

deepakgcp

@serewicz said:
You named the POD nettool, the container is named ubuntu. Try the command with nettool instead.
Could be a typo. I'll take a look and fix the material if so.

Thanks for your response sir. I already tried to login into the pod "nettool" and it worked. But the document needs to be fixed.. everywhere it is mentioned as root@ubuntu instead of root@nettool (I mean, after login into the pod).

I wonder why none of students given a feedback about this and completed the lab.

Thanks again sir.

serewicz

Thank you!

I made the pod name more unique, to nettool, and thought I changed the other references. I'll work on getting that out soon.

Regards,

chrispokorni

Hi @deepakgcp,

You can also examine the error returned by the kubectl CLI. In this case it is very specific, thus helpful, that the "ubuntu" Pod is not found. Since you have access to the YAML manifest of the Pod, it is easy to examine it and extract the name of the Pod that needs to be replaced it in the exec command. You can also use get command to list objects such as Pods by name, or describe to further display objects' details, such as container names whenever needed.

Regards,
-Chris

nmorell

It's a typo in the lab exercises, I just ran across this and knew what the issue was. The name you give the pod in the metadata field is what you use not "ubuntu"

as defined in the docs:

kubectl exec -it nettool -- /bin/bash

nmorell

I'll note there's other typos in this particular lab, for example the coredns pod does not create a PTR record based on the documentation provided for Lab 9.3, please see the following:

root@nettool:/# dig -x nginx.test.io
 
; <<>> DiG 9.16.1-Ubuntu <<>> -x nginx.test.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 15933
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
 
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;io.test.nginx.in-addr.arpa.    IN  PTR
 
;; AUTHORITY SECTION:
in-addr.arpa.       30  IN  SOA b.in-addr-servers.arpa. nstld.iana.org. 2020122003 1800 900 604800 3600
 
;; Query time: 24 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Thu Jan 21 09:16:44 CST 2021
;; MSG SIZE  rcvd: 139
 
root@nettool:/# dig nginx.test.io
 
; <<>> DiG 9.16.1-Ubuntu <<>> nginx.test.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 151
;; 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
; COOKIE: 6770800cf9fcd86f (echoed)
;; QUESTION SECTION:
;nginx.test.io.         IN  A
 
;; ANSWER SECTION:
nginx.default.svc.cluster.local. 30 IN  A   10.100.110.209
 
;; Query time: 0 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Thu Jan 21 09:16:58 CST 2021
;; MSG SIZE  rcvd: 101

$ k get cm -n kube-system coredns -o yaml
apiVersion: v1
data:
  Corefile: |
    .:53 {
        rewrite name regex (.*)\.test\.io {1}.default.svc.cluster.local
        errors
...

serewicz

Hello,

Thank you for the additional feedback. A new version of the course will be released soon with updates to the lab.

Regards,

bmaras

Hi,

I just ran into this same issue (pod named "nettool", but "ubuntu" name is still used in the PDF command).
Has the new version you mentioned be released?

chrispokorni

Hi @bmaras,

When a new course version is released you will automatically have access to it.

Regards,
-Chris