 TCP connections.</p><h2 id=envoy-is-crashing-under-load>Envoy is crashing under load</h2><p>Check your <code>ulimit -a</code>. Many systems have a 1024 open file descriptor limit by default which will cause Envoy to assert and crash with:</p><pre><code class=language-plain data-expandlinks=true data-repo=istio>[2017-05-17 03:00:52.735][14236][critical][assert] assert failure: fd_ != -1: external/envoy/source/common/network/connection_impl.cc:58
</code></pre><p>Make sure to raise your ulimit. Example: <code