Cache Invalidation

[Pinakee BIswas]

Hi,

I have deployed varnish on our production server and everything seems to 
work fine.

Right now the TTL is getting set (by backend Cache-Control) and hence, 
the cache expiry. The next goal would be to have Varnish infinitely 
cache the pages with cache invalidation.

Based on the following article:

https://www.smashingmagazine.com/2014/04/cache-invalidation-strategies-with-varnish-cache/

it seems all the mechanisms of cache invalidation are manual (using 
Purge, Ban etc.). Is there an automatic way of doing it from the 
backend? The manual process would be cumbersome as we have separate team 
for data entry/operations and they would have to notify the system 
person etc. etc.

Would appreciate if anyone could guide me to an optimal approach for the 
above.

Thanks,

Pinakee

PS: How to set the maximum value for TTL?