* Add max upstream connections dns-proxy option
Allows defining a limit to the number of connections that can be
established with the upstream DNS host.
If left unset, there may be situations where connections fail to
establish, which causes the Transport to create an influx of connections
causing upstream to throttle our requests and triggering a runaway
effect resulting in high CPU usage. See https://github.com/cloudflare/cloudflared/issues/91
* Code review with proposed changes
* Add max upstream connections flag to tunnel flags
* Reduce DNS proxy max upstream connections default value
Reduce the default value of maximum upstream connections on the DNS
proxy to guarantee it works on single-core and other low-end hardware.
Further testing could allow for a safe increase of this value.
* Update dns-proxy flag name
Also remove `MaxUpstreamConnsFlag` const as it's no longer referenced in more than one place and to make things more consistent with how the other flags are referenced.
Co-authored-by: Adam Chalmers <achalmers@cloudflare.com>
The following UInt flags:
* Uint64 - heartbeat-count, compression-quality
* Uint - retries, port, proxy-port
were not being correctly picked from the configuration YAML
since the multi origin refactor
This is due to a limitation of the ufarve library, which we
overcome for now with handling those as Int flags.
Not doing so was causing cloudflared to become stuck after
some time. This would happen because the Observer pattern
was sending events to the UI channel (that has 16 slots) but
no one was consuming those when the UI is not enabled (which
is the default case).
Hence, events (such as connection disconnect / reconnect) would
cause that buffer to be full and cause cloudflared to become
apparently stuck, in the sense that the connections would not be
reconnected.
Tunnel delete is successful even if we don't find the credentials
file in the user's filesystem. We no longer "error" indicating this
is a problem. This fix also enables chaining of the delete command
by removing a pre-mature return if the credentials file is not found.
David Jimenez
Adam Chalmers
Igor Postelnik
Nuno Diegues
TownLake
Areg Harutyunyan
Sudarsan Reddy
Michael Borkenstein
cthuang