Mongo Failover

Exploring MongoDB failover in ReplicaSet of FIVE data-bearing members across TWO datacenters.

mongo.yaml file : creates FIVE EC2 instances with the following breakdown and ONE additional EC2 instance for quick copy-paste of commands:

AWS Resource	Member Name	MongoDB Member	Availability Zone	Priority
EC2 Instance	MongoA1	PRIMARY	ap-southeast-1a	10
EC2 Instance	MongoA2	SECONDARY	ap-southeast-1a	8
EC2 Instance	MongoA3	SECONDARY	ap-southeast-1a	6
EC2 Instance	MongoB1	SECONDARY	ap-southeast-1b	4
EC2 Instance	MongoB2	SECONDARY	ap-southeast-1b	2
EC2 Instance	temp	-----	ap-southeast-1b	-

test-case.yaml file : creates SEVEN EC2 instances with the following breakdown and ONE additional EC2 instance for quick copy-paste of commands:

AWS Resource	Member Name	MongoDB Member	Availability Zone	Priority
EC2 Instance	MongoA1	PRIMARY	ap-southeast-1a	12
EC2 Instance	MongoA2	SECONDARY	ap-southeast-1a	10
EC2 Instance	MongoA3	SECONDARY	ap-southeast-1a	8
EC2 Instance	MongoB1	SECONDARY	ap-southeast-1b	6
EC2 Instance	MongoB2	SECONDARY	ap-southeast-1b	4
EC2 Instance	MongoB3	SECONDARY	ap-southeast-1b	2
EC2 Instance	MongoB4	arbiter	ap-southeast-1b	-
EC2 Instance	temp	-----	ap-southeast-1b	-

External Links

Reconfiguring a ReplicaSet:

https://docs.mongodb.com/manual/tutorial/reconfigure-replica-set-with-unavailable-members/

Adjusting Priority of Members in a ReplicaSet:

https://docs.mongodb.com/manual/tutorial/adjust-replica-set-member-priority/