Thursday, June 11, 2015

Planning large scale API Management deployment with clustering - WSO2 API Manager

When we do capacity we need to consider several factors. Here i will take basic use case as scenario and explain production recommendations.

With default configuration we can have following TPS per gateway node.
Single gateway = 1000 TPS
Single gateway by adding 30% buffer = 1300

Normally following are mandatory for HA setup

WSO2 API Manager : Gateway - 1-active. 1-passive
WSO2 API Manager : Authentication - 1-active. 1-passive
WSO2 API Manager : Publisher - 1-active. 1-passive
WSO2 API Manager : Store - 1-active. 1-passive

You can compute exact instance count

Hardware Recommendation
Physical :
3GHz Dual-core Xeon/Opteron (or latest), 4 GB RAM (minimum : 2 GB for JVM and 2GB for the OS, 10GB free disk space (minimum) disk based on the expected storage requirements (calculate by considering the file uploads and the backup policies) . (e.g if 3 Carbon instances running in a machine, it requires 4 CPU, 8 GB RAM 30 GB free space)
Virtual Machine :
2 compute units minimum (each unit having 1.0-1.2 GHz Opteron/Xeon processor) 4 GB RAM 10GB free disk space. One cpu unit for OS and one for JVM. (e.g if 3 Carbon instances running require VM of 4 compute units 8 GB RAM 30 GB free space)
EC2 : c3.large instance to run one Carbon instance. (e.g if 3 Carbon instances EC2 Extra-Large instance) Note : based on the I/O performance of c3.large instance, it is recommended to run multiple instances in a Larger instance (c3.xlarge or c3.2xlarge).


When we setup clusters normally we will have gateway cluster, store-publisher cluster and key manager clusters separately.
Let me explain why we need this.
In API Manager all store and publisher clusters need to be in same cluster as they need to do cluster communications related to registry artifacts.
When you create API from publisher it should immediately appear in store node. For this registry cache should be shared between store and publisher.
To do that replication we need to have them in single cluster.

In the same way we need to have all gateway nodes in single cluster as they need to share throttle counts and other run time specific data.

And having few(10-15) gateway nodes in single cluster will not cause any issue.
Only thing we need to keep in mind is when node count increases(within cluster) cluster communication may take very small additional time.

So in production deployments normally we will not cluster all nodes together.
Instead we will cluster gateways, key managers, Store/publishers separately.

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