Struct ciruela::cluster::Config

pub struct Config { /* fields omitted */ }

Configuration for clustered connection

More settings will be added as needed.

Methods

impl Config

pub fn new() -> Config

Create an initial config connecting to 127.0.0.1:24783

pub fn initial_connections(&mut self, num: u32) -> &mut Self

Set number of connections to initiate when accessing cluster

Default: 3.

Ciruela picks num random addresses from the ones passed to connection constructor, and connects to them initially. Then if image is not accepted at this node or if the node fails, ciruela establishes connections to other nodes keeping max num connections for any specific image upload.

In other words, this is a hint of how much simultaneous uploads might be going of any specific image. Rules of thumb:

1. Too large value means you're uploading data to more servers from a client which presumably has slower connections than local connection between nodes.
2. Small value like 1 is bad when node downloading image would fail
3. The default of 3 is just good enough

Note, that big value (1) is also not a big deal because nodes will try top optimize download anyway. Also, num=1 (2) is not big deal as ciruela will reconnect when node fails anyway. So technically any value is okay.

pub fn port(&mut self, port: u16) -> &mut Self

Set ciruela server port

This port is used both for initial connections and when redirecting connections to other host names.

pub fn early_upload(
    &mut self,
    hosts: u32,
    fraction: f32,
    timeout: Duration
) -> &mut Self

Define how to define early success of an upload

Basically this means that if after timeout we couldn't get notifications that all hosts are downloaded the image, but this number of hosts done, we stop the upload tool and report success.

The number of hosts is determined as the following:

1. Find out hosts that accept a directory, ceil(accepting_hosts*fraction)
2. If the number above is smaller than hosts we the latter instead
3. If accepting_hosts is smaller than hosts we use former

Defaults are: hosts=3, fraction=0.75, duration=30 sec

By default this provides resilience in the following ways:

1. Upload to at least three hosts (unless total hosts count is smaller)
2. Tolerate 25% of nodes currently failing
3. Do not wait full deadline if some hosts are failing because that would make deploy too long

(I.e. we need to keep the deadline huge, because 100% new/uncached image over a slow channel between CI and production might take lot of time to upload)

pub fn maximum_timeout(&mut self, timeout: Duration) -> &mut Self

Maximum time to wait before for upload before reporting failure

Default: 30 minutes

Thix timeout should be big, because 100% new/uncached image over a slow channel between CI and production might take lot of time to upload. Still default might be too pessimistic if you know your setup better.

pub fn done(&mut self) -> Arc<Config>

Finalize config and return an Arc of a config

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.