"kubectl exec" in Cygwin gets "Upgrade request required", but not in cmd shell

[Marco Atzeri]

On 14.06.2020 08:12, David Karr wrote:
> 
> 
> On Sat, Jun 13, 2020 at 10:31 PM Marco Atzeri via Cygwin wrote:
> 
>     On 13.06.2020 20:53, David Karr via Cygwin wrote:
>      > I've been using kubectl in Cygwin on Windows 10 for quite a while, to
>      > communicate to our in-house k8s clusters. I often use "kubectl
>     exec" to
>      > open a shell in a container or directly execute a shell command. 
>     This has
>      > worked perfectly fine for a long time.
>      >
>      > A couple of days ago, I discovered that all of these attempts
>     were failing
>      > with "Upgrade request required".  I hadn't upgraded kubectl or
>     Cygwin in
>      > quite a while. I doubt our clusters had a k8s upgrade, but it's
>     entirely
>      > possible.
>      >
>      > A colleague of mine has a very similar desktop configuration
>     (Windows 10,
>      > Cygwin), and he's not seeing this symptom.
>      >
>      > I noticed that when I ran "kubectl exec" with max verbosity, it
>     shows the
>      > resulting "curl" command that it runs. I tried that resulting
>     command, and
>      > it results in the same response. I then tried updating my Cygwin
>     tools and
>      > retesting, no change.
>      >
>      > I then took the entire resulting "kubectl exec" command line and
>     ran it in
>      > a "cmd" shell.  No problem at all.  No error.
>      >
>      > I know I haven't provided much useful information yet. I wanted
>     to get an
>      > initial response before I started providing those diagnostics. Is
>     there a
>      > clear issue here that I'm not aware of?
>      > --
> 
>     from where is kubectl coming from ?
> 
>     In cygwin I found only a kubectl.py in the ansible package
> 
> 
> It's from here: 
> https://kubernetes.io/docs/tasks/tools/install-kubectl/#install-kubectl-on-windows 
> .

so it is NOT a cygwin program.

If the warning is coming about curl, it is likely
that using from cygwin you are using the cygwin curl
and from CMD the windows one


$ which -a curl
/usr/bin/curl
/cygdrive/c/WINDOWS/system32/curl


$ /cygdrive/c/WINDOWS/system32/curl -V
curl 7.55.1 (Windows) libcurl/7.55.1 WinSSL
Release-Date: 2017-11-14, security patched: 2019-11-05
Protocols: dict file ftp ftps http https imap imaps pop3 pop3s smtp 
smtps telnet
  tftp
Features: AsynchDNS IPv6 Largefile SSPI Kerberos SPNEGO NTLM SSL

$ /usr/bin/curl -V
curl 7.66.0 (x86_64-pc-cygwin) libcurl/7.66.0 OpenSSL/1.1.1f zlib/1.2.11 
brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.0.4) 
libssh/0.8.7/openssl/zlib nghttp2/1.37.0
Release-Date: 2019-09-11
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps 
pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: AsynchDNS brotli Debug GSS-API HTTP2 HTTPS-proxy IDN IPv6 
Kerberos Largefile libz Metalink NTLM NTLM_WB PSL SPNEGO SSL TLS-SRP 
TrackMemory UnixSockets


the support Forum https://discuss.kubernetes.io/
is probably the most indicate place for guidance

Regards
Marco