Junos Installation - Package Validation / No validate

[syednasirraza]

hi all
I want to clarify a basic concept...When we install Junos, against what this package is
validated???and practically how if sumone can give little details??? If package is to be validated
why it says validating currrent configuration???
and if i use No-validate option, it will skip validation,,but whats good in it except
saving a minute or so because if it skips and there is some problem in validation, that problem will
be overlooked but will remain there.
Please guide...

[jozef.klacko]

Hi,

no-validate should turn off validation of current configuration against new Junos. Validation, sometimes throw some lines and stops installation, sometimes it won't show anything, but it doesn't mean that current config is fully compatible with new Junos.

As an example, we had some newer version of Junos on EX. There was a VSTP+RSTP configuration. But we had to downgrade because of some issue. Older version did not support VSTP+RSTP config, only VSTP or RSTP. We did downgrade and after restart, switch didn't initialized and didn't commited this configuration and only shows that VSTP+RSTP config is incompatible, so part of our network was down.

This was just an example when validation could warn you and disble upgrade. Validate possibly works only when upgrading.

Jozef Klacko

[erdems · Accepted solution]

Hello Nasir,

 The 'validate' knob basically checks whether the box you're installating the software to is compatible or not, based on its configuration (juniper.conf) and some other things (like the PIC layout in some platforms).

 In other words, validate is used to ensure that the box will not reboot with an unstable configuration and/or state. Examples would be that the upgrade will fail if you have graceful-switchover enabled, or if you have a knob in your configuration that is no longer supported with your destination release.

 Like you've pointed out, the 'no-validate' option is going to make the upgrade process quite faster, but you're bypassing most sanity checks as you've suspected, so MUST be used with caution.

 Cheers,

[syednasirraza]

hi josef and erdems

thanks to BOTH of u for such a good explanation