Netscaler lost console access after HA pair was upgraded to 13.1 build 37.38 and received the following error on console:

Jan 10 21:39:49 ... getty[24784]: tcsetattr /dev/ttyu0: Operation not supported

Jan 10 21:39:49 ... getty[24785]: getty: unknown gettytab entry '3wire'

Jan 10 21:39:49 ... syslogd: last message repeated 1 times Jan 10 

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Please log into the Netscaler via CLI

1. Go to shell,
2. Inside /ETC directory, delete the gettytab file (if present)
3. Inside /NSCONFIG directory, delete the gettytab file (if present)
4. Inside /NSCONFIG directory, edit file RC.NETSCALERand delete the following lines (if present)
   1. cp /nsconfig/gettytab /etc
   2. cp /nsconfig/gettytab /etc
   3. echo "default::cb:ce:ck:lc:fd#1000:im=\r\n`hostname` :sp#1200::if=/etc/issue:" >> /etc/gettytab
5. Reboot Netscaler
   1. Previous steps didn't modify the current config, please save the correct configuration before rebooting.

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Problem Cause

What triggers the issue
 

• Command that triggers this is set consoleloginprompt "TEXT" 
  • This command changed the prompt in the console, it was used for version 12.0 and previous ones.

 
> set consoleloginprompt "michael" 
 Done
> 

• The command basically does 3 things:
  1. Copy gettytab file from /etc to /nsconfig folder
  2. Add a line “default::cb:ce:ck:lc:fd#1000:im=\r\michael :sp#1200::if=/etc/issue:” in the new /nsconfig/gettytab file
  3. Finally copy the line “cp /nsconfig/gettytab /etc” in rc.netscaler in order to keep the changes after a reboot.

 
Why modifying gettytab make an issue
 

• Gettytab file is for character interpretation. Each time we press a key it helps to display the correct character on the console. If it has any issue we wont be able to work propertly on the console and generate caracter errors.

 
Why issue showns on 13.1 and not 13.0, 12.0 and 10.0
 
When the command 'set consoleloginprompt' is executed we do modify the file /etc/gettytab to reflect the change in the prompt by replacing the default entry with a new one including the new prompt string , using the example above:
 
root@sp_adc_13_0# grep ^default /nsconfig/gettytab 
“default::cb:ce:ck:lc:fd#1000:im=\r\michael :sp#1200::if=/etc/issue:”
 
That works fine until 13.0 because we use FreeBSD 8 as the base until that release. Starting with 13.1 we migrated to FreeBSD 11. From the man page of FreeBSD 11:  https://man.freebsd.org/cgi/man.cgi?query=gettytab&apropos=0&sektion=0&manpath=FreeBSD+11.2-RELEASE&arch=default&format=html


 

Summary: to solve the problem, follow the steps below to delete customed scripts inside gettytab file.