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plugin/forward: remove exp backoff stuff (#3970)

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we hc every 0.5s, doing exp backoff will create a large gap in the
ability to re-use an upstream. Doing a exp. backoff up to (say) 3s,
isn't really exp backoff either.

Remove the wording from the documentation.

Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben
2020-06-24 16:49:06 +02:00
committed by GitHub
parent 8647592786
commit 55e9c2cd7b
1 changed files with 6 additions and 8 deletions
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14
plugin/forward/README.md
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@@ -9,14 +9,12 @@
The *forward* plugin re-uses already opened sockets to the upstreams. It supports UDP, TCP and
DNS-over-TLS and uses in band health checking.
When it detects an error a health check is performed. This checks runs in a loop, starting with
a *0.5s* interval and exponentially backing off with randomized intervals up to *15s* for as long
as the upstream reports unhealthy. The exponential backoff will reset to *0.5s* after 2 minutes.
Once healthy we stop health checking (until the next error). The health checks use a recursive
DNS query (`. IN NS`) to get upstream health. Any response that is not a network error (REFUSED,
NOTIMPL, SERVFAIL, etc) is taken as a healthy upstream. The health check uses the same protocol as
specified in **TO**. If `max_fails` is set to 0, no checking is performed and upstreams will always
be considered healthy.
When it detects an error a health check is performed. This checks runs in a loop, performing each
check at a *0.5s* interval for as long as the upstream reports unhealthy. Once healthy we stop
health checking (until the next error). The health checks use a recursive DNS query (`. IN NS`)
to get upstream health. Any response that is not a network error (REFUSED, NOTIMPL, SERVFAIL, etc)
is taken as a healthy upstream. The health check uses the same protocol as specified in **TO**. If
`max_fails` is set to 0, no checking is performed and upstreams will always be considered healthy.
When *all* upstreams are down it assumes health checking as a mechanism has failed and will try to
connect to a random upstream (which may or may not work).