100 Days of Learning: Day 0 – Serverless, OpenFaaS and Multipass

Today I started a 100 Day challenge to learn about new things.

See my Log book for more information about my challenge.

The first topic I want to learn about is the idea of Function as a Service (FaaS) and to start off on this journey I will be working through Alex Ellis’ Serverless for Everyone Else book.

Next I will go over the steps I took to get my first function deployed on my Mac.

Installing Multipass

Follow the instructions at: https://multipass.run/ for macOS

• Download and run the installer as an Admin user

• Spin up an Ubuntu instance, test and delete

  Spin up (this took about 5 minutes the first time to get the latest Ubuntu LTS image)

    $ multipass launch --name test
    Launched: test
  

  Test a command

    $ multipass exec test -- lsb_release -a
    No LSB modules are available.
    Distributor ID:	Ubuntu
    Description:	Ubuntu 20.04.2 LTS
    Release:	20.04
    Codename:	focal
  

  List instances

    $ multipass list
    Name     State      IPv4            Image
    test     Running    192.168.64.2    Ubuntu 20.04 LTS
  

  Stop and clean up $ multipass stop test $ multipass delete test $ multipass purge

Installing faasd

• Create a new Ubuntu instance using multipass

  2 cores and 2 gigs of RAM

    $ multipass launch --name faasd --cpus 2 --mem 2G
    Launched: faasd
  

• Open a bash shell on the Ubuntu instance

    $ multipass exec faasd /bin/bash 
    To run a command as administrator (user "root"), use "sudo <command>".
    See "man sudo_root" for details.
  
    ubuntu@faasd:~$
  

  

• Copy your ssh public key over to the instance so we can run ssh sessions directly against the instance

  NOTE: See the last section on how to create a SSH key if you don’t already have one.

    $ cat ~/.ssh/id_rsa.pub | pbcopy
    [pbcopy copies to the clipboard on macOS]
    
    Edit the authorized ssh keys for the instance and add the id_rsa.pub value
    ubuntu@faasd:~$ nano ~/.ssh/authorized_keys
  

• Test ssh to the instance. Open a new terminal.

  Get the IP address of the instance

    $ multipass info faasd
    Name:           faasd
    State:          Running
    IPv4:           192.168.64.4
    Release:        Ubuntu 20.04.2 LTS
    Image hash:     c5f2f08c6a1a (Ubuntu 20.04 LTS)
    Load:           0.00 0.00 0.00
    Disk usage:     1.2G out of 4.7G
    Memory usage:   148.6M out of 1.9G		
  

  SSH into the instance (note: ubuntu is the default username)

    $ ssh ubuntu@192.168.64.4
  

  In my case because I have multiple keys for a number of services and because of the way my ~/.ssh/config file is setup, I need to explicitly state to use PreferredAuthentications=publickey

    $ ssh -i ~/.ssh/id_rsa -o PreferredAuthentications=publickey ubuntu@192.168.64.4
  

• Now you have two ways to get a shell on the running instance

    $ multipass exec faasd /bin/bash
    or
    $ ssh ubuntu@INSTANCE_IP
  

• Install faasd on the instance

  Drop to root user (just incase sudo fails along the way)

    ubuntu@faasd:~$ sudo -i
    root@faasd:~#
  

  Clone the repo

    root@faasd:~# git clone https://github.com/openfaas/faasd --depth=1
    Cloning into 'faasd'...
    ...
  

  Install

    root@faasd:~# cd faasd
    root@faasd:~# ./hack/install.sh
    ...
    Creating alias 'faas' for 'faas-cli'.
      ___                   _____           ____
     / _ \ _ __   ___ _ __ |  ___|_ _  __ _/ ___|
    | | | | '_ \ / _ \ '_ \| |_ / _` |/ _` \___ \
    | |_| | |_) |  __/ | | |  _| (_| | (_| |___) |
     \___/| .__/ \___|_| |_|_|  \__,_|\__,_|____/
          |_|
    
    CLI:
     commit:  6b5e7a14a598527063c7c05fb4187739b6eb6d38
     version: 0.13.6
  

  Verify faasd is running

    root@faasd:~/faasd# systemctl status faasd
    ● faasd.service - faasd
         Loaded: loaded (/lib/systemd/system/faasd.service; enabled; vendor preset: enabled)
         Active: active (running) since Mon 2021-03-08 20:25:14 GMT; 5min ago
       Main PID: 14201 (faasd)
          Tasks: 7 (limit: 2344)
         Memory: 37.8M (limit: 500.0M)
         CGroup: /system.slice/faasd.service
                 └─14201 /usr/local/bin/faasd up
  

Deploying your first function

I will be using the UI (web portal) for exploring the faasd setup as well as deploy my first FaaS.

• Get the admin user’s password

    ubuntu@faasd:~$ sudo cat /var/lib/faasd/secrets/basic-auth-password ;echo
    zI24jRLe45DhUPa21S6BoNy5q1DpYUb0FuDwlLfUoBNo6yaDBMZEPTO2W3K
  

• Open up the UI in your browser. E.g. http://INSTANCE_IP:8080

• Provide username "admin" and the password from the previous steps

  

• Select "Deploy New Function" and search for "ASCII Cows". Deploy it.

• After a few seconds or so you will see COWS in the sidebar. Select it.

• Invoke the function and you will get a random ascii cow

• You can also run curl against the deployed function

    $ curl http://192.168.64.4:8080/function/cows
    *        (__)
     \       (OO)
      \-------\/
       /     \\
      //------\\
     ^^        ^^
    Cow who's just
    seen a McDonalds
  

Miscellaneous

Creating a SSH key-pair

I like to have a SSH key-pair per machine or service I use and store a backup copy in my password manager (1Password). For this example I will just create the default id_rsa key pair that will also be used for connecting to the Ubuntu local instances.

Run the following command to create a 4kb RSA public and private key-pair. The filenames will be id_rsa (the private key, never ever share this one!) and id_rsa.pub (the public key)

$ ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa -C "Add a comment here if you want"

I use the password manager to generate a strong passphrase. To rule out any copy/paste and unrecoverable errors in the future, I like to copy/paste the stored secret from my recording (password manager entry) and then when asked to confirm, I manually type it in. This way I can be sure that what I copy/paste will always be correct and at the very least I would be able to manually type it in if the need ever presented itself.

Backup the generated key-pair (~/.ssh/id_rsa and ~/.ssh/id_rsa.pub) to your password manager. Tip: To see hidden files on macOS (in Finder or File dialogue) enter Cmd + Shift + . (period for dot files).

Add the key to your macOS login keychain so you don’t have to always enter the passphrase.

$ ssh-add -K ~/.ssh/id_rsa