Intro

OpenFAAS is a serverless tool. One of the things I like most about it - it’s pretty agnostic. You can bring your own infra or orchestrator and roll with Dockerfiles (as long as they conform to the OpenFaas serverless workload definition). No vendor lock in!

Their tagline: OpenFaaS® makes it simple to deploy both functions and existing code to Kubernetes

While OpenFaas is mainly used with k8s, there are other providers available too. We’ll be experimenting with one of those (Faasd) in this post. The cloud of choice is Openstack based and we’ll be using Terraform to manage our cloud resources within it.

The Terraform required to make all this work is in this repository.

Why would I want to do this?

You probably don’t outside of curiosity. Personally, I want to do serverless on the edge with out the complexity and overhead of K8s. This is a cool way to achieve that!

Prerequisites

  1. You’ll need an openstack project with the following resources available to consume:

    • One Instance (and enough VCPU’s and RAM for it)
    • One Floating IP
    • One Security Group
    • One Network
    • One Router

    You’ll also want to make sure that you are able to connect to your cloud’s APIs via the CLI. Note that Terraform supports authentication using both the newer application credentials via clouds.yaml or Environment Variables.

  2. Download Terraform. It will need to be available on your $PATH.

  3. Clone this repo

    git clone https://github.com/markopolo123/openstack-faasd.git
     # move into the repository directory:
    cd openstack-faasd
    
  4. Define variables in variables.tfvars

    We’ll need to create a file called variables.tfvars in the root of this project and populate with variables; required ones are shown below:

    cat variables.tfvars
    
    letsencrypt_email = "Your email here"
    public_url      = "faasd.url.here"
    static_fip      = "1.2.3.4" # preallocated Floating IP
    public_network  = "" # Public Network ID for your Floating IP
    image_name      = "CentOS-8-GenericCloud-8.1.1911-20200113.3" # Your image name here
    dns_nameservers = ["8.8.8.8", "8.8.4.4"] # DNS if needed
    flavor_name     = "C1.openstack.tiny" # Flavor type here
    

    Note that here the Floating IP has been pre allocated to the project - this is due to limitations with DNS CNAME records in the cloud available to me.

    There are more variables we could define here, for instance, we could change the versions of containerd or faasd. Check out variables.tf for a full list of variables for this project.

  5. Run commands in the Makefile

    The Terraform commands have been wrapped in a Makefile to make things easier for us. It’s pretty simple, but saves us having to remember a few flags/options on our terraform commands.

    Command Explanation
    make help lists available commands
    make plan Generates a plan of action for Terraform
    make apply Applies the plan generated in the last step
    make destroy Destroys the cloud resources
    make output Displays the output

    NOTE: The state file is local, which will probably not be what you want for a production instance. While we are at it - you will probably not want your OpenFaas password randomly generated and stored in your state file too. You have been warned ;)

  6. Enjoy OpenFaas

    The Terraform run completes in a few seconds, however cloud-init will take a minute or two to run through the sequence of commands required to get us up and running.

    After the Terraform run is finished you will be presented with the output

    Outputs:
    
    gateway_url = https://your.url.here/
    login_cmd = faas-cli login -g https://your.url.here/ -p passwordhere
    password = passwordhere
    

Example

Not much to see here, but just in case: