Commit 86b39ed4 authored by ale's avatar ale

convert documentation to Markdown

parent 220eb0c1
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======================
autoradio Tuning Guide
======================
......@@ -10,8 +9,7 @@ box in testing environments, most real-world deployments will require
some tuning.
Etcd
----
# Etcd
The default settings for etcd are tuned for a local (LAN) network
environment. In the case of a geographically distributed cluster,
......@@ -23,7 +21,7 @@ in your cluster, while the election timeout should be at least 3 times
the heartbeat interval.
With our etcd package, you can set these values in
``/etc/default/etcd`` (values are milliseconds)::
`/etc/default/etcd` (values are milliseconds):
DAEMON_OPTS="--peer-heartbeat-interval=1000 --peer-election-timeout=3000"
......@@ -33,17 +31,15 @@ node failure. It is advisable that the radiod master election ttl is
set to a value greater than the etcd peer election timeout.
Radiod timeouts
---------------
# Radiod timeouts
Similar considerations, with respect to latency, apply to the presence
and master-election protocols that are run by autoradio itself. These
are controlled by radiod's ``--heartbeat`` and
``--master-election-ttl`` command-line flags. For these time values,
though, there are further considerations to be made:
are controlled by radiod's `--heartbeat` and `--master-election-ttl`
command-line flags. For these time values, though, there are further
considerations to be made:
Presence
~~~~~~~~
## Presence
The node presence heartbeat sets the lower time bound for peers to
discover that a node is down, and stop sending client requests to it.
......@@ -61,8 +57,7 @@ reloads of the full configuration, causing even more unnecessary
network traffic and increasing the load on etcd.
Master Election
~~~~~~~~~~~~~~~
## Master Election
The node master election timeout determines how quickly a source
(assuming it retries continuously on error) will be able to reconnect
......@@ -70,8 +65,7 @@ to the cluster if the node that is currently the master becomes
unavailable.
Capacity
--------
# Capacity
One of the nice properties of the autoradio traffic control logic is
the ability to reject incoming traffic when the cluster reaches its
......@@ -85,12 +79,12 @@ Autoradio models capacity along two separate dimensions: bandwidth
(outbound), and number of connected listeners. CPU/memory are not
included due to their negligible incremental cost per-request. Limits
can be set separately for each node in the cluster, by passing the
``--bwlimit`` and ``--max-clients`` command-line flags to ``radiod``.
`--bwlimit` and `--max-clients` command-line flags to *radiod*.
The traffic control logic is then able to use utilization metrics to
make decisions about where to send traffic. For details on how this is
done, and how to control it, check the Go source documentation for the
``fe/lbv2`` package.
`fe/lbv2` package.
The default traffic control policy only checks the number of
listeners: this is because it usually makes the most sense to express
......
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