Knative#

Lithops with Knative as serverless compute backend. Lithops also supports vanilla Knative for running applications. The easiest way to make it working is to create an IBM Kubernetes (IKS) cluster through the IBM dashboard. Alternatively you can use your own kubernetes cluster or a kind/minikube installation.

Installation#

Note that Lithops automatically builds the default runtime the first time you run a script. For this task it uses the docker command installed locally in your machine.

  1. Install the Docker CE version.

  2. Login to your docker account:

    docker login
    
  3. Choose one of these 3 installation options:

Option 1 - Minikube:#

  1. Start minikube with the ‘ingress’ addon:

    minikube start --addons=ingress
    
  2. Follow this instructions to install knative serving.

  3. Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

  4. Edit your lithops config and add:

    knative:
        ingress_endpoint : http://127.0.0.1:80
    
  5. On a separate terminal, keep running:

    minikube tunnel
    

Option 2 - IBM IKS:#

  1. Access to the IBM dashboard and create a new Kubernetes cluster.

  2. Once the cluster is running, follow the instructions of the “Actions”–> “Connect via CLI” option of the dashboard to configure the kubectl client in your local machine.

  3. Follow this instructions to install knative serving.

  4. Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

Option 3 - IBM IKS or any other Kubernetes Cluster:#

  1. Install Kubernetes >= v1.16 and make sure the kubectl client is running.

  2. Follow this instructions to install knative serving.

  3. Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

Configuration#

  1. Make sure you have the ~/.kube/config file. Alternatively, you can set KUBECONFIG environment variable:

    export KUBECONFIG=<path-to-kube-config-file>
    
  2. Edit your lithops config and add the following keys:

    lithops:
        backend: knative
    

Configure a private container registry for your runtime#

Configure Docker hub#

To configure Lithops to access a private repository in your docker hub account, you need to extend the Knative config and add the following keys:

knative:
    ....
    docker_server    : docker.io
    docker_user      : <Docker hub Username>
    docker_password  : <DOcker hub access TOEKN>

Configure IBM Container Registry#

To configure Lithops to access to a private repository in your IBM Container Registry, you need to extend the Knative config and add the following keys:

knative:
    ....
    docker_server    : us.icr.io
    docker_user      : iamapikey
    docker_password  : <IBM IAM API KEY>

Summary of configuration keys for Knative:#

Group

Key

Default

Mandatory

Additional info

knative

ingress_endpoint

no

Ingress endpoint. Make sure to use http:// prefix

knative

kubecfg_path

no

Path to kubecfg file. Mandatory if config file not in ~/.kube/config or KUBECONFIG env var not present

knative

docker_server

docker.io

no

Docker server URL

knative

docker_user

no

Docker hub username

knative

docker_password

no

Login to your docker hub account and generate a new access token here

knative

git_url

no

Git repository to build the image

knative

git_rev

no

Git revision to build the image

knative

max_workers

250

no

Max number of workers per FunctionExecutor()

knative

worker_processes

1

no

Number of Lithops processes within a given worker. This can be used to parallelize function activations within a worker. It is recommendable to set this value to the same number of CPUs of the container.

knative

runtime

no

Docker image name

knative

runtime_cpu

0.5

no

CPU limit. Default 0.5vCPU

knative

runtime_memory

256

no

Memory limit in MB. Default 256Mi

knative

runtime_timeout

600

no

Runtime timeout in seconds. Default 600 seconds

knative

invoke_pool_threads

250

no

Number of concurrent threads used for invocation

Verify#

  1. Verify that all the pods from the following namespaces are in Running status:

    kubectl get pods -n knative-serving
    
  2. Monitor how pods and other resources are created:

    watch kubectl get pod,service,revision,deployment -o wide
    

Test Lithops#

Once you have your compute and storage backends configured, you can run a hello world function with:

lithops test -b knative -s ibm_cos

Viewing the execution logs#

You can view the function executions logs in your local machine using the lithops client:

lithops logs poll