FaaSCache, is a transparent, vertically and horizontally elastic in-memory caching system for Function as a Service platforms. The cache is distributed over worker nodes to mitigate the overheads of frequent interactions with an external data store, as required by the stateless FaaS paradigm. FaaSCache is based on enhancements to the Apache OpenWhisk FaaS platform, the OpenStack Swift persistent object storage service, and the RAMCloud in-memory store.

• customRuntime contains our custom Openwhisk image that embeds the proxy and write-back routines.

• datasets contains the datasets used for our multimedia and audio processing functions.

• faasLoad contains the source code our custom load injector for OpenWhisk, which allows emulating several tenants with different workloads.

• functions contains the source code of a set of single and pipeline functions.

• IMOC embeds the custom Ramcloud, OpenWhisk-core and OpenStackSwift used for FAASCache.

The current version of FAASCACHE relies on three components, OpenWhisk, RAMCloud, and OpenStackSwift. Below, we show how to deploy these components and connect them.

Openjdk >= 8; Gradle >= 5.0.0; gcc == 5.4, 4.8; Docker

The first step is building our custom version of openwhisk-core. It is the central part of the OpenWhisk since it embeds logic to store, launch, schedule, and report user functions. We customized it to introduce our scheduling enhancements, a scala library to communicate with RAMCloud controller nodes, and a scala integration of our machine learning routines to predicts function memory usage. It is relatively easy to build:

git clone https://github.com/djobiii2078/FAASCACHE.git   
cd IMOC/openwhisk-core/
./gradlew :core:standalone:build

If everything went right, there should be a openwhisk.jar created in IMOC/openwhisk-core/bin folder. Now, you should create an image docker based on our previous build. It is recommended to save the image on Docker Hub but it can work with a locally built image.

Locally openwhisk docker image

./gradlew :core:standalone:distDocker

Or save the image on your Docker Hub

docker login #enter your credentials
./gradlew :core:standalone:distDocker

In both cases, you will see whisk/standalone in your docker image list (docker images).

We use RAMCloud as our object caching system. RAMCloud is a RAM-based durable key-value store. We customized RAMCloud to introduce autoscaling, persistence, and consistency routines. The following steps describe how you can build our custom-based RAMCloud:

cd IMOC/RAMCloud/
chmod +x install.sh
./install.sh

As shown on the figure below, a minimal FAASCACHE deployment includes an openwhisk controller and a RAMCloud coordinator on the same node, two openwhisk invoker nodes, and an OpenStackSwift node. On each openwhisk invoker node runs a RAMCloud server instance.

Let's consider this table for the next steps:

Starting the RAMCloud cluster

First, build RAMCloud on each RAMCloud node (coordinator and invoker nodes).

On the RAMCloud controller node, start a RAMCloud controller instance

RAMCloud/obj.master/coordinator -C tcp:host=`hostname -s`,port=11100 -x \
	zk:localhost:2181

On each RAMCloud invoker node, start a RAMCloud master instance:

RAMCloud/obj.master/server -L tcp:host=`hostname -s`,port=1101 -x \
	zk:@owk_contr:2181 --totalMasterMemory 4096 -f \
		~/backup --segmentFrames 1500 -r 1 --allowLocalBackup

This creates an instance of a RAMCloud coordinator which can use up to 4GB of memory to cache objects. For more details on this command inputs, please checkout the official RAMCloud documentation page.

Deploying OpenWhisk cluster kubernetes mode

The steps are the same as native OpenWhisk. However, you must use our update version in IMOC/openwhisk-cluster-mode. Don't forget to update your .yaml to update the image of the openwhisk-core used.

Use "whisk/controller" for a local image however, if your image is on a Docker Hub, you will need to update the imageName tag.

controller:
 imageName: "whisk/controller"
 imageTag: "latest"

@invoker1 and @invoker2 must correspond to the node where the RAMCloud master's are deployed.

Deploying OpenStackSwift and associated modules Deploying OpenStackSwift is straightforward. Follow step by step, the instructions in custom swift setup

Wrapping up

To finish the setup, we will install custom utility FAAS functions.