scale.io

loadbalancing and autoscaling module for websocket based EC2 cluster without ELB.

architecture

• no ELB

• slack based monitoring

• zero downtime deploy
• multi-AZ based
• auto fail over

how to use

scale.js

require('scale.io');

set config yml file

set config/default.yaml or config/env.yaml your main app.

Example is this.

execute

node --harmony scale.js

config details

conf for redis / aws / slack

enter your

• redis host & port
• access key id, secret access key and region
• slack info

conf for loadbalancing / autoscaling / monitoring

enter some info (details are below).

conf for loadbalancing

Correspond to A and B in above structure chart.

key	desc
timeoutThresholdForRedHost	Getting no response within this value(ms), host is regard as RedHost(=DyingHost).
connNumForRedHost	RedHost is expressed by this value at loadbalancing log.
ec2HostTagKey	EC2 tag key
ec2HostTagValueForLobby	EC2 tag value for lobby server.
ec2HostTagValueForGame	EC2 tag value for game server.
intervalForAutoscalingSec	cycle time of autoscale watching process
intervalForHostInfoUpdateSec	cycle time of loadbalancing process
redisKeyForLobbyLoadbalancing	redis key name for lobby loadbalance.
redisKeyForGameLoadbalancing	redis key name for game loadbalance.

conf for autoscaling

Correspond to C in above structure chart.

key	desc
cfnStackName	stack name of cloudformation.
serverTypeNum	server type number. if you use lobby and game, enter 2.
scaleOutThreshold	average connection number of instances for scale out.
scaleInThreshold	average connection number of instances for scale in.
cfnUpdateCmd	update cloudformation command.
minimumGreenHostsNum	falling below this value, scale out starts.
forceScaleOutStartAt	scale out forced to start after this time.
forceScaleOutEndAt	scale out forced to start before this time.
scaleInAvailableStartAt	scale in can be started after this time.
scaleInAvailableEndAt	scale in can be started after this time.
notifyRoomNumMessage	notifying message by slack.
scaleInMinimumIntervalSec	scale in can be started countinuously after this interval.
scaleOutMinimumIntervalSec	scale out can be started countinuously after this interval.
specifiedTimeGreenHostsNum	instance number will be change to this value between specified time.
restartCmd	restart autoscale process commond.
autoRestartCpuUsageThresholdForLB	if cpu usage exceed this value, process restart.
autoRestartMonitorIntervalSec	monitoring span for auto restart.

conf for monitor

Correspond to D in above structure chart.

key	desc
monitoredHost	monitored target.
monitoredProcess	like 'game', 'lobby'
monitoringIntervalSec	monitoring span
decisionIntervalSec	monitored process does not reply throughout this span, it is regard as died.