fnlb-test-harness

README

fnlb-test-harness

Test harness that exercises the fnlb load balancer in order to verify that it works properly.

How it works

This is a test harness that makes calls to an Fn route through the fnlb load balancer, which routes traffic to multiple Fn nodes. The test harness keeps track of which node each request was routed to so we can assess how the requests are being distributed across the nodes. The functionality of fnlb is to normally route traffic to the same small number of nodes so that efficiences can be achieved and to support reuse of hot functions.

Primes function

The test harness utilizes the "primes" function, which calculates prime numbers as an excuse for consuming CPU resources. The function is invoked as follows:

curl http://host:8080/r/primesapp/primes?max=1000000&loops=1

where:

• max: calculate all primes <= max (increasing max will increase memory usage, due to the Sieve of Eratosthenes algorithm)
• loops: number of times to calculate the primes (repeating the count consumes additional CPU without consuming additional memory)

How to use it

The test harness requires running one or more Fn nodes and one instance of fnlb. The list of nodes must be provided both to fnlb and to the test harness because the test harness must call each node directly one time in order to discover the node's container id.

After it has run, examine the results to see how the requests were distributed across the nodes.

How to run it locally

Each of the Fn nodes needs to connect to the same database.

STEP 1: Create a route for the primes function. Example:

fn apps create primesapp
fn routes create primesapp /primes jconning/primes:0.0.1

STEP 2: Run five Fn nodes locally. Example (runs five nodes in the background using Docker):

sudo docker run -d -it --name functions-8082 --privileged -v ${HOME}/data-8082:/app/data -p 8082:8080 -e "DB_URL=postgres://dbUser:dbPassword@dbHost:5432/dbName" fnproject/fnserver
sudo docker run -d -it --name functions-8083 --privileged -v ${HOME}/data-8083:/app/data -p 8083:8080 -e "DB_URL=postgres://dbUser:dbPassword@dbHost:5432/dbName" fnproject/fnserver
sudo docker run -d -it --name functions-8084 --privileged -v ${HOME}/data-8084:/app/data -p 8084:8080 -e "DB_URL=postgres://dbUser:dbPassword@dbHost:5432/dbName" fnproject/fnserver
sudo docker run -d -it --name functions-8085 --privileged -v ${HOME}/data-8085:/app/data -p 8085:8080 -e "DB_URL=postgres://dbUser:dbPassword@dbHost:5432/dbName" fnproject/fnserver
sudo docker run -d -it --name functions-8086 --privileged -v ${HOME}/data-8086:/app/data -p 8086:8080 -e "DB_URL=postgres://dbUser:dbPassword@dbHost:5432/dbName" fnproject/fnserver

STEP 3: Run fnlb locally. Example (runs fnlb on the default port 8081):

fnlb -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086

STEP 4: Run the test harness. Note that the 'nodes' parameter should be the same that was used with fnlb. Example:

cd functions/test/fnlb-test-harness
go run main.go -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086 -calls 10 -v

STEP 5: Examine the output to determine how many times fnlb called each node. Assess whether it is working properly.

Usage

go run main.go -help

Command line parameters:

• -calls: number of times to call the route (default 100)
• -lb: host and port of load balancer (default "localhost:8081")
• -loops: number of times to execute the primes calculation (ex: '-loops 2' means run the primes calculation twice) (default 1)
• -max: maximum number to search for primes (higher number consumes more memory) (default 1000000)
• -nodes: comma-delimited list of nodes (host:port) balanced by the load balancer (needed to discover container id of each) (default "localhost:8080")
• -route: path representing the route to the primes function (default "/r/primesapp/primes")
• -v: flag indicating verbose output

Examples: quick vs long running

Quick function:: calculate primes up to 1000

go run main.go -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086 -max 1000 -v

where -max is default of 1M, -calls is default of 100, -route is default of "/r/primesapp/primes", -lb is default localhost:8081

Normal function: calculate primes up to 1M

go run main.go -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086 -v

where -max is default of 1M, -calls is default of 100, -route is default of "/r/primesapp/primes", -lb is default localhost:8081

Longer running function: calculate primes up to 1M and perform the calculation ten times

go run main.go -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086 -loops 10 -v

where -max is default of 1M, -calls is default of 100, -route is default of "/r/primesapp/primes", -lb is default localhost:8081

1000 calls to the route: send 1000 requests through the load balancer

go run main.go -nodes localhost:8082,localhost:8083,localhost:8084,localhost:8085,localhost:8086 -calls 1000 -v

where -max is default of 1M, -calls is default of 100, -route is default of "/r/primesapp/primes", -lb is default localhost:8081

Planned Enhancements

• Create 1000 routes and distribute calls amongst them.
• Use concurrent programming to enable the test harness to call multiple routes at the same time.