First of all, you are not using the Pushgateway (PGW) for what it is
designed for.
In fact, the PGW doesn't impose any limitation on the request size,
simply because its inteded usecases never get anywhere close to a
request size that would require limitation. Therefore, there is no
setting for the request size, either.
I strongly assume that the 413 HTTP error is coming from something in
between, most likely nginx.
--
Björn Rabenstein
[PGP-ID] 0x851C3DA17D748D03
[email]
bjo...@rabenste.in