There are a bunch of things to test/check/keep in mind when it comes to the upgrade to Varnish 4. Let's collect them in this subtask.
- figure out if varnish4 still has the problem that old VCL shared object continue to consume memory
- remember to use std.ip() instead of ipcast.ip() while porting VCL code
- check if varnishlog and varnishncsa are properly started by puppet
- vmod-tbf sucked at startup time: "at daemon start, everyone's already at the limit". fix the module code and/or our parameter input to make sure we err on the lax side with ratelimits on fresh start
- figure out how to make sure vmod-tbf deallocates the ip db memory on VCL reload
- check for threads_failed. Set thread_pool_add_delay (now in floating-point seconds) if it grows too much
- vslp has no per-backend weighting. We can't assume we won't need differential weighting of hardware generations so it might be necessary to add backend weighting as a feature to libvmod-vslp
- do_stream defaults are reversed and do_stream lacks downsides - be sure to make per-cluster conditional do_stream code varnish3-only during VCL conversions, for later removal once we're all-varnish4.