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.

Install the Docker CE version.
Login to your docker account:
```
docker login
```
Choose one of these 3 installation options:

Option 1 - Minikube:#

Start minikube with the ‘ingress’ addon:
```
minikube start --addons=ingress
```
Follow this instructions to install knative serving.
Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

Edit your lithops config and add:

knative:
    ingress_endpoint : http://127.0.0.1:80

On a separate terminal, keep running:
```
minikube tunnel
```

Option 2 - IBM IKS:#

Access to the IBM dashboard and create a new Kubernetes cluster.
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.
Follow this instructions to install knative serving.
Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

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

Install Kubernetes >= v1.16 and make sure the kubectl client is running.
Follow this instructions to install knative serving.
Install a networking layer. Currently Lithops supports Kourier. Follow these instructions to install Kourier.

Configuration#

Make sure you have the ~/.kube/config file. Alternatively, you can set KUBECONFIG environment variable:
```
export KUBECONFIG=<path-to-kube-config-file>
```
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>
    docker_namespace : <namespace>  # namespace name from https://cloud.ibm.com/registry/namespaces

Summary of configuration keys for Knative:#

Group	Key	Default	Mandatory	Additional info
knative	kubecfg_path		no	Path to kubecfg file. Mandatory if config file not in `~/.kube/config` or KUBECONFIG env var not present
knative	networking_layer	kourier	no	One of: kourier or istio
knative	ingress_endpoint		no	Ingress endpoint. Make sure to use http:// prefix
knative	docker_server	docker.io	no	Container registry URL
knative	docker_user		no	Container registry user name
knative	docker_password		no	Container registry password/token. In case of Docker hub, 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	100	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	1	no	CPU limit. Default 1vCPU
knative	runtime_memory	512	no	Memory limit in MB. Default 512
knative	runtime_timeout	600	no	Runtime timeout in seconds. Default 600 seconds
knative	invoke_pool_threads	100	no	Number of concurrent threads used for invocation

Verify#

Verify that all the pods from the following namespaces are in Running status:
```
kubectl get pods -n knative-serving
```

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 hello -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

Knative

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