diff --git a/ci/vale/dictionary.txt b/ci/vale/dictionary.txt index c1b9a0b15b..566a16650e 100644 --- a/ci/vale/dictionary.txt +++ b/ci/vale/dictionary.txt @@ -1247,6 +1247,7 @@ klei klocwork kloth kloxo +knative knockpy knowledgebase Kodu @@ -1255,6 +1256,7 @@ Konqueror konsole konversation kotin +kourier KPI KPIs krita diff --git a/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Docker-Hub-Get-Emojis.png b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Docker-Hub-Get-Emojis.png new file mode 100644 index 0000000000..8488ec7279 Binary files /dev/null and b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Docker-Hub-Get-Emojis.png differ diff --git a/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Kubernetes-Dashboard.png b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Kubernetes-Dashboard.png new file mode 100644 index 0000000000..be7d2a2dcd Binary files /dev/null and b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/Kubernetes-Dashboard.png differ diff --git a/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/index.md b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/index.md new file mode 100644 index 0000000000..3b94724245 --- /dev/null +++ b/docs/guides/kubernetes/migrating-from-aws-lambda-to-knative/index.md @@ -0,0 +1,1134 @@ +--- +slug: migrating-from-aws-lambda-to-knative +title: "Migrating from AWS Lambda to Knative" +description: "Learn how to migrate from AWS Lambda to Knative for a flexible, open source, cloud-native serverless platform on Kubernetes." +authors: ["Akamai"] +contributors: ["Akamai"] +published: 2024-09-19 +keywords: ['knative','lambda','kubernetes','aws lambda migration','aws lambda alternatives','knative migration','knative vs lambda','knative serverless','knative kubernetes'] +license: '[CC BY-ND 4.0](https://creativecommons.org/licenses/by-nd/4.0)' +external_resources: +- '[Knative](https://knative.dev/docs/)' +- '[Knative Functions](https://knative.dev/docs/functions/)' +- '[Knative Functions - Deep Dive (Video)](https://www.youtube.com/watch?v=l0EooTOGW84)' +- '[Accessing request traces - Knative](https://knative.dev/docs/serving/accessing-traces/)' +- '[Migrating from AWS Lambda to Knative Functions](https://knative.dev/blog/articles/aws_to_func_migration/)' +- '[GitHub: boson-project/parliament](https://github.com/boson-project/parliament)' +- '[Logging and Metrics with Amazon CloudWatch](https://docs.aws.amazon.com/lambda/latest/operatorguide/logging-metrics.html)' +- '[Prometheus](https://prometheus.io)' +- '[Grafana Labs - Loki, Grafana, Tempo, Mimir](https://grafana.com)' +- '[OpenTelemetry](https://opentelemetry.io)' +- '[Sample AWS Lambda function](https://github.com/the-gigi/fuzz-emoji/tree/main/aws_lambda)' +- '[Sample Knative function (Python)](https://github.com/the-gigi/fuzz-emoji/tree/main/knative_functions/python)' +--- + +Knative is an open source platform that extends Kubernetes to manage serverless workloads. It provides tools to deploy, run, and manage serverless applications and functions, enabling automatic scaling and efficient resource usage. Knative consists of several components: + +- **Serving**: Deploys and runs serverless containers. +- **Eventing**: Facilitates event-driven architectures. +- **Functions**: Deploys and runs functions locally and on Kubernetes. + +This guide walks through the process of migrating an AWS Lambda function to a Knative function running on the Linode Kubernetes Engine (LKE). + +## Before You Begin + +1. Read our [Getting Started with Linode](/docs/products/platform/get-started/) guide, and create a Linode account if you do not already have one. + +1. Create a personal access token using the instructions in our [Manage personal access tokens](https://techdocs.akamai.com/cloud-computing/docs/manage-personal-access-tokens) guide. + +1. Ensure that you have [Git](https://git-scm.com/downloads) installed. + +1. Follow the steps in the *Install kubectl* section of our [Getting started with LKE](https://techdocs.akamai.com/cloud-computing/docs/getting-started-with-lke-linode-kubernetes-engine) guide to install `kubectl`. + +1. Install the Linode CLI using the instructions in our [Install and configure the CLI](https://techdocs.akamai.com/cloud-computing/docs/install-and-configure-the-cli) guide. + +1. Ensure that you have Knative's [`func` CLI](https://knative.dev/docs/functions/install-func/) installed. + +1. Ensure that you have [Docker](https://www.docker.com/products/docker-desktop/) installed and have a [Docker Hub](https://www.docker.com/products/docker-hub/) account. + +1. Install `jq`, a lightweight command line JSON processor: + + ```command + sudo apt install jq + ``` + +{{< note >}} +This guide is written for a non-root user. Commands that require elevated privileges are prefixed with `sudo`. If you’re not familiar with the `sudo` command, see the [Users and Groups](/docs/guides/linux-users-and-groups/) guide. +{{< /note >}} + +## Provision a Kubernetes Cluster + +While there are several ways to create a Kubernetes cluster on Linode, this guide uses the [Linode CLI](https://github.com/linode/linode-cli) to provision resources. + +1. Use the Linode CLI command (`linode`) to see available Kubernetes versions: + + ```command + linode lke versions-list + ``` + + ```output + ┌──────┐ + │ id │ + ├──────┤ + │ 1.31 │ + ├──────┤ + │ 1.30 │ + ├──────┤ + │ 1.29 │ + └──────┘ + ``` + + It's generally recommended to provision the latest version of Kubernetes unless specific requirements dictate otherwise. + +1. Use the following command to list available Linode plans, including plan ID, pricing, and performance details. For more detailed pricing information, see [Akamai Connected Cloud: Pricing](https://www.linode.com/pricing/): + + ```command + linode linodes types + ``` + +1. The examples in this guide use the **g6-standard-2** Linode, which features two CPU cores and 4 GB of memory. Run the following command to display detailed information in JSON for this Linode plan: + + ```command + linode linodes types --label "Linode 4GB" --json --pretty + ``` + + ```output + [ + { + "addons": { + "backups": { + "price": { + "hourly": 0.008, + "monthly": 5.0 + }, + "region_prices": [ + { + "hourly": 0.009, + "id": "id-cgk", + "monthly": 6.0 + }, + { + "hourly": 0.01, + "id": "br-gru", + "monthly": 7.0 + } + ] + } + }, + "class": "standard", + "disk": 81920, + "gpus": 0, + "id": "g6-standard-2", + "label": "Linode 4GB", + "memory": 4096, + "network_out": 4000, + "price": { + "hourly": 0.036, + "monthly": 24.0 + }, + "region_prices": [ + { + "hourly": 0.043, + "id": "id-cgk", + "monthly": 28.8 + }, + { + "hourly": 0.05, + "id": "br-gru", + "monthly": 33.6 + } + ], + "successor": null, + "transfer": 4000, + "vcpus": 2 + } + ] + ``` + +1. View available regions with the `regions list` command: + + ```command + linode regions list + ``` + +1. With a Kubernetes version and Linode type selected, use the following command to create a cluster named `knative-playground` in the `us-mia` (Miami, FL) region with three nodes and auto-scaling. Replace {{< placeholder "knative-playground" >}} and {{< placeholder "us-mia" >}} with a cluster label and region of your choosing, respectively: + + ```command + linode lke cluster-create \ + --label {{< placeholder "knative-playground" >}} \ + --k8s_version 1.31 \ + --region {{< placeholder "us-mia" >}} \ + --node_pools '[{ + "type": "g6-standard-2", + "count": 3, + "autoscaler": { + "enabled": true, + "min": 3, + "max": 8 + } + }]' + ``` + + Once your cluster is successfully created, you should see output similar to the following: + + ```output + Using default values: {}; use the --no-defaults flag to disable defaults + ┌────────────────────┬────────┬─────────────┐ + │ label │ region │ k8s_version │ + ├────────────────────┼────────┼─────────────┤ + │ knative-playground │ us-mia │ 1.31 │ + └────────────────────┴────────┴─────────────┘ + ``` + +### Access the Kubernetes Cluster + +To access your cluster, fetch the cluster credentials in the form of a `kubeconfig` file. + +1. Use the following command to retrieve the cluster's ID: + + ```command + CLUSTER_ID=$(linode lke clusters-list --json | \ + jq -r \ + '.[] | select(.label == "knative-playground") | .id') + ``` + +1. Create a hidden `.kube` folder in your user's home directory: + + ```command + mkdir ~/.kube + ``` + +1. Retrieve the `kubeconfig` file and save it to `~/.kube/lke-config`: + + ```command + linode lke kubeconfig-view --json "$CLUSTER_ID" | \ + jq -r '.[0].kubeconfig' | \ + base64 --decode > ~/.kube/lke-config + ``` + +1. Once you have the `kubeconfig` file saved, access your cluster by using `kubectl` and specifying the file: + + ```command + kubectl get no --kubeconfig ~/.kube/lke-config + ``` + + ```output + NAME STATUS ROLES AGE VERSION + lke242177-380780-1261b5670000 Ready 49s v1.31.0 + lke242177-380780-3496ef070000 Ready 47s v1.31.0 + lke242177-380780-53e2290c0000 Ready 51s v1.31.0 + ``` + + {{< note >}} + Optionally, to avoid specifying `--kubeconfig ~/.kube/lke-config` with every `kubectl` command, you can set an environment variable for your current terminal session: + + ```command + export KUBECONFIG=~/.kube/lke-config + ``` + + Then run: + + ```command + kubectl get no + ``` + {{< /note >}} + +## Set Up Knative on LKE + +There are multiple ways to [install Knative on a Kubernetes cluster](https://knative.dev/docs/install/). The examples in this guide use the YAML manifests method. + +1. Run the following command to install the Knative CRDs: + + ```command + RELEASE=releases/download/knative-v1.15.2/serving-crds.yaml + kubectl apply -f "https://github.com/knative/serving/$RELEASE" + ``` + + Upon successful execution, you should see a similar output indicating that the CRDs are configured: + + ```output + customresourcedefinition.apiextensions.k8s.io/certificates.networking.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/configurations.serving.knative.dev created + customresourcedefinition.apiextensions.k8s.io/clusterdomainclaims.networking.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/domainmappings.serving.knative.dev created + customresourcedefinition.apiextensions.k8s.io/ingresses.networking.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/metrics.autoscaling.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/podautoscalers.autoscaling.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/revisions.serving.knative.dev created + customresourcedefinition.apiextensions.k8s.io/routes.serving.knative.dev created + customresourcedefinition.apiextensions.k8s.io/serverlessservices.networking.internal.knative.dev created + customresourcedefinition.apiextensions.k8s.io/services.serving.knative.dev created + customresourcedefinition.apiextensions.k8s.io/images.caching.internal.knative.dev created + ``` + +1. Next, install the Knative **Serving** component: + + ```command + RELEASE=releases/download/knative-v1.15.2/serving-core.yaml + kubectl apply -f "https://github.com/knative/serving/$RELEASE" + ``` + + You should see similar output indicating that various resources are now created: + + ```output + namespace/knative-serving created + role.rbac.authorization.k8s.io/knative-serving-activator created + clusterrole.rbac.authorization.k8s.io/knative-serving-activator-cluster created + clusterrole.rbac.authorization.k8s.io/knative-serving-aggregated-addressable-resolver created + clusterrole.rbac.authorization.k8s.io/knative-serving-addressable-resolver created + clusterrole.rbac.authorization.k8s.io/knative-serving-namespaced-admin created + clusterrole.rbac.authorization.k8s.io/knative-serving-namespaced-edit created + clusterrole.rbac.authorization.k8s.io/knative-serving-namespaced-view created + clusterrole.rbac.authorization.k8s.io/knative-serving-core created + clusterrole.rbac.authorization.k8s.io/knative-serving-podspecable-binding created + serviceaccount/controller created + clusterrole.rbac.authorization.k8s.io/knative-serving-admin created + clusterrolebinding.rbac.authorization.k8s.io/knative-serving-controller-admin created + clusterrolebinding.rbac.authorization.k8s.io/knative-serving-controller-addressable-resolver created + serviceaccount/activator created + rolebinding.rbac.authorization.k8s.io/knative-serving-activator created + clusterrolebinding.rbac.authorization.k8s.io/knative-serving-activator-cluster created + customresourcedefinition.apiextensions.k8s.io/images.caching.internal.knative.dev unchanged + certificate.networking.internal.knative.dev/routing-serving-certs created + customresourcedefinition.apiextensions.k8s.io/certificates.networking.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/configurations.serving.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/clusterdomainclaims.networking.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/domainmappings.serving.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/ingresses.networking.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/metrics.autoscaling.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/podautoscalers.autoscaling.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/revisions.serving.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/routes.serving.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/serverlessservices.networking.internal.knative.dev unchanged + customresourcedefinition.apiextensions.k8s.io/services.serving.knative.dev unchanged + image.caching.internal.knative.dev/queue-proxy created + configmap/config-autoscaler created + configmap/config-certmanager created + configmap/config-defaults created + configmap/config-deployment created + configmap/config-domain created + configmap/config-features created + configmap/config-gc created + configmap/config-leader-election created + configmap/config-logging created + configmap/config-network created + configmap/config-observability created + configmap/config-tracing created + horizontalpodautoscaler.autoscaling/activator created + poddisruptionbudget.policy/activator-pdb created + deployment.apps/activator created + service/activator-service created + deployment.apps/autoscaler created + service/autoscaler created + deployment.apps/controller created + service/controller created + horizontalpodautoscaler.autoscaling/webhook created + poddisruptionbudget.policy/webhook-pdb created + deployment.apps/webhook created + service/webhook created + validatingwebhookconfiguration.admissionregistration.k8s.io/config.webhook.serving.knative.dev created + mutatingwebhookconfiguration.admissionregistration.k8s.io/webhook.serving.knative.dev created + validatingwebhookconfiguration.admissionregistration.k8s.io/validation.webhook.serving.knative.dev created + secret/webhook-certs created + ``` + +1. Knative relies on an underlying networking layer. [Kourier](https://github.com/knative-extensions/net-kourier) is designed specifically for Knative, and the examples in this guide use Kourier for [Knative networking](https://knative.dev/docs/install/operator/knative-with-operators/#install-the-networking-layer). Use the commands below to download and install the latest Kourier release: + + ```command + RELEASE=releases/download/knative-v1.15.1/kourier.yaml + kubectl apply -f "https://github.com/knative-extensions/net-kourier/$RELEASE" + ``` + + The output should again indicate the creation of multiple new elements: + + ```output + namespace/kourier-system created + configmap/kourier-bootstrap created + configmap/config-kourier created + serviceaccount/net-kourier created + clusterrole.rbac.authorization.k8s.io/net-kourier created + clusterrolebinding.rbac.authorization.k8s.io/net-kourier created + deployment.apps/net-kourier-controller created + service/net-kourier-controller created + deployment.apps/3scale-kourier-gateway created + service/kourier created + service/kourier-internal created + horizontalpodautoscaler.autoscaling/3scale-kourier-gateway created + poddisruptionbudget.policy/3scale-kourier-gateway-pdb created + ``` + +1. The following command configures Knative to use Kourier as the default ingress controller: + + ```command + kubectl patch configmap/config-network \ + --namespace knative-serving \ + --type merge \ + --patch \ + '{"data":{"ingress-class":"kourier.ingress.networking.knative.dev"}}' + ``` + + ```output + configmap/config-network patched + ``` + + {{< note >}} + If Istio is already installed in your cluster, you may choose to [reuse it for Knative](https://knative.dev/docs/install/operator/knative-with-operators/#__tabbed_1_2) as well. + {{< /note >}} + +1. With Kourier configured, the Knative Serving installation now has a [`LoadBalancer`](https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer) service for external access. Use the following command to retrieve the external IP address in case you want to set up your own DNS later: + + ```command + kubectl get service kourier -n kourier-system + ``` + + The output should display the external IP address of the `LoadBalancer`: + + ```output + NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE + kourier LoadBalancer 10.128.48.124 172.235.159.7 80:31938/TCP,443:30800/TCP 4m37s + ``` + +1. Since Kourier added several deployments, check the updated list to ensure everything is functioning correctly: + + ```command + kubectl get deploy -n knative-serving + ``` + + Use the output to confirm availability of the various components: + + ```output + NAME READY UP-TO-DATE AVAILABLE AGE + activator 1/1 1 1 7m36s + autoscaler 1/1 1 1 7m36s + controller 1/1 1 1 7m36s + net-kourier-controller 1/1 1 1 5m7s + webhook 1/1 1 1 7m36s + ``` + +1. This guide uses the Magic DNS method to [configure DNS](https://knative.dev/docs/install/operator/knative-with-operators/#configure-dns), which leverages the [sslip.io](http://sslip.io) DNS service. When a request is made to a subdomain of sslip.io containing an embedded IP address, the service resolves that IP address. For example, a request to [https://52.0.56.137.sslip.io](https://52.0.56.137.sslip.io) returns `52.0.56.137` as the IP address. Use the `default-domain` job to configure Knative Serving to use sslip.io: + + ```command + MANIFEST=knative-v1.15.2/serving-default-domain.yaml + kubectl apply -f "https://github.com/knative/serving/releases/download/$MANIFEST" + ``` + + Upon successful execution, you should see output confirming the creation of the `default-domain` job and service: + + ```output + job.batch/default-domain created + service/default-domain-service created + ``` + +With Knative now operational in your cluster, you can begin working with Knative Functions. + +## Work with Knative Functions and the `func` CLI + +Knative Functions is a programming model that simplifies writing distributed applications on Kubernetes and Knative. It allows developers to create stateless, event-driven functions without requiring in-depth knowledge of containers, Kubernetes, or Knative itself. + +The [`func`](https://github.com/knative/func) CLI streamlines the developer experience by providing tools to work with Knative Functions. It allows developers to manage the entire lifecycle of functions (creating, building, deploying, and invoking). This allows for local development and testing of functions without the need for a local Kubernetes cluster. + +1. To get started, run the following command: + + ```command + func + ``` + + This displays help information for managing Knative Function resources: + + ```output + func is the command line interface for managing Knative Function resources + + Create a new Node.js function in the current directory: + func create --language node myfunction + + Deploy the function using Docker hub to host the image: + func deploy --registry docker.io/alice + + Learn more about Functions: https://knative.dev/docs/functions/ + Learn more about Knative at: https://knative.dev + + Primary Commands: + create Create a function + describe Describe a function + deploy Deploy a function + delete Undeploy a function + list List deployed functions + subscribe Subscribe a function to events + + Development Commands: + run Run the function locally + invoke Invoke a local or remote function + build Build a function container + + System Commands: + config Configure a function + languages List available function language runtimes + templates List available function source templates + repository Manage installed template repositories + environment Display function execution environment information + + Other Commands: + completion Output functions shell completion code + version Function client version information + + Use "func --help" for more information about a given command. + ``` + +1. Use the following command to create an example Python function (`get-emojis`) that can be invoked via an HTTP endpoint (the default invocation method): + + ```command + func create -l python get-emojis + ``` + + This command creates a complete directory structure with multiple files: + + ```output + Created python function in /home/{{< placeholder "USERNAME" >}}/get-emojis + ``` + +1. Examine the contents of the newly created `~/get-emojis` directory: + + ```command + ls -laGh get-emojis + ``` + + ```output + total 48K + drwxr-xr-x 3 {{< placeholder "USERNAME" >}} 4.0K Oct 9 15:57 . + drwxr-x--- 9 {{< placeholder "USERNAME" >}} 4.0K Oct 9 15:57 .. + -rwxr-xr-x 1 {{< placeholder "USERNAME" >}} 55 Oct 9 15:57 app.sh + drwxrwxr-x 2 {{< placeholder "USERNAME" >}} 4.0K Oct 9 15:57 .func + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 217 Oct 9 15:57 .funcignore + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 1.8K Oct 9 15:57 func.py + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 97 Oct 9 15:57 func.yaml + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 235 Oct 9 15:57 .gitignore + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 28 Oct 9 15:57 Procfile + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 862 Oct 9 15:57 README.md + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 28 Oct 9 15:57 requirements.txt + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 259 Oct 9 15:57 test_func.py + ``` + +1. While reviewing the purpose of each file is outside the scope of this guide, you should examine the `func.py` file, the default implementation that Knative generates: + + ```command + cat ~/get-emojis/func.py + ``` + + ```file {title="~/get-emojis/func.py" lang="python"} + from parliament import Context + from flask import Request + import json + + + # parse request body, json data or URL query parameters + def payload_print(req: Request) -> str: + if req.method == "POST": + if req.is_json: + return json.dumps(req.json) + "\n" + else: + # MultiDict needs some iteration + ret = "{" + + for key in req.form.keys(): + ret += '"' + key + '": "'+ req.form[key] + '", ' + + return ret[:-2] + "}\n" if len(ret) > 2 else "{}" + + elif req.method == "GET": + # MultiDict needs some iteration + ret = "{" + + for key in req.args.keys(): + ret += '"' + key + '": "' + req.args[key] + '", ' + + return ret[:-2] + "}\n" if len(ret) > 2 else "{}" + + + # pretty print the request to stdout instantaneously + def pretty_print(req: Request) -> str: + ret = str(req.method) + ' ' + str(req.url) + ' ' + str(req.host) + '\n' + for (header, values) in req.headers: + ret += " " + str(header) + ": " + values + '\n' + + if req.method == "POST": + ret += "Request body:\n" + ret += " " + payload_print(req) + '\n' + + elif req.method == "GET": + ret += "URL Query String:\n" + ret += " " + payload_print(req) + '\n' + + return ret + + + def main(context: Context): + """ + Function template + The context parameter contains the Flask request object and any + CloudEvent received with the request. + """ + + # Add your business logic here + print("Received request") + + if 'request' in context.keys(): + ret = pretty_print(context.request) + print(ret, flush=True) + return payload_print(context.request), 200 + else: + print("Empty request", flush=True) + return "{}", 200 + ``` + + Note that this function acts as a server that returns the query parameters or form fields of incoming requests. + +### Build a Function Image + +The next step is to create a container image from your function. Since the function is intended run on a Kubernetes cluster, it must be containerized. Knative Functions facilitates this process for developers, abstracting the complexities of Docker and Dockerfiles. + +1. Navigate into the `~/get-emojis` directory: + + ```command + cd ~/get-emojis + ``` + +1. To build your function, run the following `build` command while in the `~/get-emojis` directory, specifying Docker Hub (`docker.io`) as the registry along with your {{< placeholder "DOCKER_HUB_USERNAME" >}}: + + ```command + func build --registry docker.io/{{< placeholder "DOCKER_HUB_USERNAME" >}} + ``` + + This command fetches a base image and builds a Docker image from your function. You should see output similar to the following as the function image is built: + + ```output + Building function image + Still building + Still building + Yes, still building + Don't give up on me + Still building + This is taking a while + 🙌 Function built: index.docker.io/{{< placeholder "DOCKER_HUB_USERNAME" >}}/get-emojis:latest + ``` + +1. To verify that the image is successfully created, use the following command to list your Docker images: + + ```command + docker images | grep -E 'knative|get-emojis|ID' + ``` + + ```output + REPOSITORY TAG IMAGE ID CREATED SIZE + ghcr.io/knative/builder-jammy-base 0.4.283 204e70721072 44 years ago 1.45GB + {{< placeholder "DOCKER_HUB_USERNAME" >}}/get-emojis latest {{< placeholder "IMAGE_ID" >}} 44 years ago 293MB + ``` + + {{< note >}} + While the `CREATED` timestamp may be incorrect, the image is valid. + {{< /note >}} + +1. Use the `run` command to run the function locally: + + ```command + func run + ``` + + The terminal should display output indicating that the function now runs on `localhost` at port `8080`.: + + ```output + function up-to-date. Force rebuild with --build + Running on host port 8080 + ``` + +1. With your function running, open a second terminal session and enter the following command: + + ```command + curl "http://localhost:8080?a=1&b=2" + ``` + + By default, this initial implementation returns the URL query parameters as a JSON object. The resulting output should be: + + ```output + {"a": "1", "b": "2"} + ``` + + Meanwhile, you should see the output similar to the following in your original terminal window: + + ```output + Received request + GET http://localhost:8080/?a=1&b=2 localhost:8080 + Host: localhost:8080 + User-Agent: curl/7.81.0 + Accept: */* + URL Query String: + {"a": "1", "b": "2"} + ``` + +1. When done, close the second terminal and stop the function in the original terminal by pressing the CTRL+C keys. + +### Deploy the Function + +1. Use the `deploy` command to deploy your function to your Kubernetes cluster as a Knative function and push it to the Docker registry: + + ```command + func deploy + ``` + + ```output + function up-to-date. Force rebuild with --build + Pushing function image to the registry "index.docker.io" using the "{{< placeholder "DOCKER_HUB_USERNAME" >}}" user credentials + 🎯 Creating Triggers on the cluster + ✅ Function deployed in namespace "default" and exposed at URL: + http://get-emojis.default.{{< placeholder "IP_ADDRESS" >}}.sslip.io + ``` + + Once the function is deployed and the Magic DNS record is established, your Knative function is accessible through this public HTTP endpoint. The new `get-emojis` repository should also now exist on your Docker Hub account: + + ![The get-emojis repository on Docker Hub.](Docker-Hub-Get-Emojis.png) + +1. To invoke your Knative function, `curl` the function’s public URL, adding any required query parameters. For example: + + ```command + curl http://get-emojis.default.{{< placeholder "IP_ADDRESS" >}}.sslip.io/?yeah=it-works! + ``` + + The output should display a JSON object containing the query parameters: + + ```output + {"yeah": "it-works!"} + ``` + +With your Knative function running, the next step is migrate an AWS Lambda function to Knative. + +## Migrate Your AWS Lambda Function to Knative + +This guide examines a sample Lambda function and walks through how to migrate it to Knative. Conceptually, Lambda functions are similar to Knative functions. They both have a trigger and extract their input arguments from a context or event. + +The main application logic is highlighted in the example Lambda function below: + +```file {lang="python" hl_lines="15-16"} +def handler(event, context): + try: + logger.info("Received event: %s", event) + + # The descriptions may arrive as attribute of the event + descriptions = event.get("descriptions") + if descriptions is None: + # Parse the JSON body of the event + body = json.loads(event.get("body", "{}")) + logger.info("Parsed body: %s", body) + + descriptions = body.get("descriptions", []) + logger.info("Descriptions: %s", descriptions) + + fuzz_emoji = FuzzEmoji() + result = fuzz_emoji.get_emojis(descriptions) + response = { + 'statusCode': 200, + 'body': json.dumps(result) + } + except Exception as e: + response = { + 'statusCode': 500, + 'body': json.dumps({'error': str(e)}) + } + + return response +``` + +This example function instantiates a `FuzzEmoji` object and calls its `get_emojis()` method, passing a list of emoji descriptions. The emoji descriptions may or may not map to official emoji names like `fire` (🔥) or `confused_face` (😕). The function performs a "fuzzy" search of the descriptions to find matching emojis. + +The code above the highlighted lines extracts emoji descriptions from the `event` object passed to the handler. The code below the highlighted lines wraps the result in a response with a proper status code for success or failure. + +At the time of this writing, this sample Lambda function was deployed and available at the following HTTP endpoint: + +```command +curl -s -X POST --header "Content-type:application/json" \ + --data '{"descriptions":["flame","confused"]}' \ + https://64856ijzmi.execute-api.us-west-2.amazonaws.com/default/fuzz-emoji | \ + json_pp +``` + +Invoking the function returns the following result: + +```output +{ + "confused" : "('confused_face', '😕')", + "flame" : "('fire', '🔥')" +} +``` + +The function successfully returns the `fire` (🔥) emoji for the description "flame", and the `confused_face` emoji (😕) for the description "confused.” + +### Isolating the AWS Lambda Code from AWS Specifics + +To migrate the Lambda function to Knative, the core application logic must be decoupled from AWS-specific dependencies. In this case, the function's main logic is already isolated. The `get_emojis()` method only accepts a list of strings as input, which makes it more adaptable for other platforms. + +If the `get_emojis()` method were dependent on the AWS Lambda `event` object, it would not be compatible with Knative and would require some refactoring, as Knative does not provide an `event` object. + +### Migrating a Single-File Function to a Knative Function + +The core logic of the function is encapsulated into a single Python module named `fuzz_emoji.py`, which can be migrated to your Knative function. + +1. Using a text editor of your choice, create the `fuzz_emoji.py` file in the `get-emojis` directory: + + ```command + nano ~/get-emojis/fuzz_emoji.py + ``` + + Give the file the following content: + + ```file {title="~/get-emojis/fuzz_emoji/py" lang="python"} + from typing import List, Mapping, Tuple + + import emoji + import requests + + class FuzzEmoji: + def __init__(self): + self.emoji_dict = {} + emoji_list = {name: data for name, data in emoji.EMOJI_DATA.items() if 'en' in data} + for emoji_char, data in emoji_list.items(): + name = data['en'].strip(':') + self.emoji_dict[name.lower()] = emoji_char + + @staticmethod + def get_synonyms(word): + response = requests.get(f"https://api.datamuse.com/words?rel_syn={word}") + if response.status_code == 200: + synonyms = [word_data['word'] for word_data in response.json()] + return synonyms + + raise RuntimeError(response.content) + + def get_emoji(self, description) -> Tuple[str, str]: + description = description.lower() + # direct match + if description in self.emoji_dict: + return description, self.emoji_dict[description] + + # Subset match + for name in self.emoji_dict: + if description in name: + return name, self.emoji_dict[name] + + synonyms = self.get_synonyms(description) + # Synonym match + for syn in synonyms: + if syn in self.emoji_dict: + return syn, self.emoji_dict[syn] + return '', '' + + def get_emojis(self, descriptions: List[str]) -> Mapping[str, str]: + return {d: str(self.get_emoji(d)) for d in descriptions} + ``` + + When complete, save your changes. + +1. Run the `ls` command: + + ```command + ls -laGh ~/get-emojis/ + ``` + + The folder structure should now look like this: + + ```output + total 52K + drwxr-xr-x 3 {{< placeholder "USERNAME" >}} 4.0K Oct 10 17:32 . + drwxr-x--- 9 {{< placeholder "USERNAME" >}} 4.0K Oct 10 16:51 .. + -rwxr-xr-x 1 {{< placeholder "USERNAME" >}} 55 Oct 10 16:51 app.sh + drwxrwxr-x 3 {{< placeholder "USERNAME" >}} 4.0K Oct 10 17:20 .func + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 217 Oct 10 16:51 .funcignore + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 1.8K Oct 10 16:51 func.py + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 317 Oct 10 17:22 func.yaml + -rw-rw-r-- 1 {{< placeholder "USERNAME" >}} 1.4K Oct 10 17:32 fuzz_emoji.py + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 235 Oct 10 16:51 .gitignore + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 28 Oct 10 16:51 Procfile + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 862 Oct 10 16:51 README.md + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 28 Oct 10 16:51 requirements.txt + -rw-r--r-- 1 {{< placeholder "USERNAME" >}} 259 Oct 10 16:51 test_func.py + ``` + +1. Edit your `func.py` file so that it calls the `fuzz_emoji` module: + + ```command + nano ~/get-emojis/func.py + ``` + + Insert or adjust the highlighted lines so that the contents of your `fuzz_emoji.py` file appear as below. Remember to save your changes: + + ```file {title="~/get-emojis/func.py" lang="python" hl_lines="4,34,61-64"} + from parliament import Context + from flask import Request + import json + from fuzz_emoji import FuzzEmoji + + + # parse request body, json data or URL query parameters + def payload_print(req: Request) -> str: + if req.method == "POST": + if req.is_json: + return json.dumps(req.json) + "\n" + else: + # MultiDict needs some iteration + ret = "{" + + for key in req.form.keys(): + ret += '"' + key + '": "'+ req.form[key] + '", ' + + return ret[:-2] + "}\n" if len(ret) > 2 else "{}" + + elif req.method == "GET": + # MultiDict needs some iteration + ret = "{" + + for key in req.args.keys(): + ret += '"' + key + '": "' + req.args[key] + '", ' + + return ret[:-2] + "}\n" if len(ret) > 2 else "{}" + + + # pretty print the request to stdout instantaneously + def pretty_print(req: Request) -> str: + ret = str(req.method) + ' ' + str(req.url) + ' ' + str(req.host) + '\n' + for header, values in req.headers.items(): + ret += " " + str(header) + ": " + values + '\n' + + if req.method == "POST": + ret += "Request body:\n" + ret += " " + payload_print(req) + '\n' + + elif req.method == "GET": + ret += "URL Query String:\n" + ret += " " + payload_print(req) + '\n' + + return ret + + + def main(context: Context): + """ + Function template + The context parameter contains the Flask request object and any + CloudEvent received with the request. + """ + + # Add your business logic here + print("Received request") + + if 'request' in context.keys(): + ret = pretty_print(context.request) + print(ret, flush=True) + descriptions = context.request.args.get('descriptions').split(',') + fuzz_emoji = FuzzEmoji() + result = fuzz_emoji.get_emojis(descriptions) + return json.dumps(result, ensure_ascii=False), 200 + else: + print("Empty request", flush=True) + return "{}", 200 + ``` + + Below is a breakdown of the file code functionality: + + - Imports the built-in `json`, the `Context` from [parliament](https://github.com/boson-project/parliament) (the function invocation framework that Knative uses for Python functions), and the `FuzzEmoji` class. + - The `main()` function accepts the parliament `Context` as its only parameter, which contains a Flask `request` property. + - The first line extracts the emoji descriptions from the Flask `request` arguments. It expects the descriptions to be a single comma-separated string, which it splits into a list of `descriptions`. + - Instantiates a `FuzzEmoji` object and calls the `get_emojis()` method. + - Uses the `json` module to serialize the response and return it with a `200` status code. + +1. Next, edit the `requirements.txt` file to include the dependencies of `fuzz_emoji.py` (the `requests` and `emoji` packages) in the Docker image: + + ```command + nano ~/get-emojis/requirements.txt + ``` + + Append the highlighted lines to the end of the file, and save your changes: + + ```file {title="~/get-emojis/requirements.txt" hl_lines="2,3"} + parliament-functions==0.1.0 + emoji==2.12.1 + requests==2.32.3 + ``` + +1. Re-build and re-deploy the container: + + ```command + func build --registry docker.io/{{< placeholder "DOCKER_HUB_USERNAME" >}} + func deploy + ``` + +1. Test your function using the public URL: + + ```command + curl http://get-emojis.default.{{< placeholder "IP_ADDRESS" >}}.sslip.io/?descriptions=cold,plane,fam + ``` + + The `descriptions` provided as a query parameter are echoed back, along with a corresponding emoji name and emoji for each description: + + ```output + {"cold": "('cold_face', '🥶')", "plane": "('airplane', '✈')", "fam": "('family', '👪')"} + ``` + + This confirms that the Knative function works as expected. + +### Migrating a Multi-File Function to a Knative Function + +In the previous example, the entire application logic was contained in a single file called `fuzz_emoji.py`. For larger workloads, your function may involve multiple files or multiple directories and packages. + +Migrating such a setup to Knative follows a similar process: + +1. Copy all relevant files and directories into the same `get-emojis` directory. + +1. Import any required modules in `func.py`. + +1. Update the `requirements.txt` file to include all of the dependencies used across any of the modules. + +### Migrating External Dependencies + +When migrating an AWS Lambda function, it may depend on various AWS services such as S3, DynamoDB, or SQS. It's important to evaluate each dependency to determine the best option to suit your situation. + +There are typically three options to consider: + +1. **Keep it as-is**: Continue using the Knative function to interact with the AWS service. + +1. **Replace the service**: For example, you might switch from an AWS service like DynamoDB to an alternative key-value store in the Kubernetes cluster. + +1. **Drop the functionality**: Eliminate certain AWS-specific functionalities, such as no longer writing messages to AWS SQS. + +### Namespace and Service Account + +The Knative function eventually runs as a pod in the Kubernetes cluster. This means it runs in a namespace and has a Kubernetes service account associated with it. These are determined when you run the `func deploy` command. You can specify them using the `-n` (or `--namespace`) and `--service-account` arguments. + +If these options are not specified, the function deploys in the currently configured namespace and uses the default service account of the namespace. + +If your Knative function needs to access any Kubernetes resources, it’s recommended to explicitly specify a dedicated namespace and create a dedicated service account. This is the preferred approach since it avoids granting excessive permissions to the default service account. + +### Configuration and Secrets + +If your AWS Lambda function uses `ParameterStore` and `SecretsManager` for configuration and sensitive information, these details should not be embedded directly in the function's image. For example, if your function needs to access AWS services, it would require AWS credentials to authenticate. + +Kubernetes offers the [`ConfigMap`](https://kubernetes.io/docs/concepts/configuration/configmap/) and [`Secret`](https://kubernetes.io/docs/concepts/configuration/secret/) resources for this purpose. The migration process involves the following steps: + +1. Identify all the parameters and secrets the Lambda function uses. + +1. Create corresponding `ConfigMap` and `Secret` resources in the namespace for your Knative function. + +1. Grant the service account for your Knative function permissions to read `ConfigMap` and `Secret`. + +### Roles and Permissions + +Your Knative function may need to interact with various Kubernetes resources and services during migration, such as data stores, `ConfigMaps`, and `Secrets`. To enable this, create a dedicated role with the necessary permissions and bind it to the function's service account. + +If your architecture includes multiple Knative functions, it is considered a best practice to share the same service account, role, and role bindings between all the Knative functions. + +### Logging, Metrics, and Distributed Tracing + +The logging experience in Knative is similar to printing something in your AWS Lambda function. In AWS Lambda, output is automatically logged to CloudWatch. In Knative, that same print statement automatically sends log messages to your container's logs. If you have centralized logging, these messages are automatically recorded in your log system. + +LKE provides the native Kubernetes dashboard by default. It runs on the control plane, so it doesn't take resources from your workloads. You can use the dashboard to explore and monitor your entire cluster: + +![The default Kubernetes Dashboard showing workload status and deployments.](Kubernetes-Dashboard.png) + +For production systems, consider using a centralized logging system like ELK/EFK, Loki, or Graylog, along with an observability solution consisting of Prometheus and Grafana. You can also supplement your observability by leveraging a telemetry data-oriented solution such as OpenTelemetry. These tools can enhance your ability to monitor, troubleshoot, and optimize application performance while ensuring reliability and scalability. + +Knative also has built-in support for distributed tracing, which can be configured globally. This means your Knative function automatically participates in tracing without requiring additional changes. + +### The Debugging Experience + +Knative offers debugging at multiple levels: + +- Unit test your core logic +- Unit test your Knative function +- Invoke your function locally + +When you create a Python Knative function, Knative generates a skeleton for a unit test called `test_func.py`. At the time of this writing, the generated test is invalid and requires some modifications to work correctly. See this [GitHub issue](https://github.com/knative/func/issues/2448) for details. + +1. Open the `test_func.py` file in the `get-emojis` directory: + + ```command + nano ~/get-emojis/test_func.py + ``` + + Replace its content with the test code below, and save your changes. This code is updated for testing the fuzzy emoji search functionality: + + ```file {title="~/get-emojis/test_func.py" lang="python"} + import unittest + from parliament import Context + + func = __import__("func") + + class DummyRequest: + def __init__(self, descriptions): + self.descriptions = descriptions + + @property + def args(self): + return dict(descriptions=self.descriptions) + + @property + def method(self): + return 'GET' + + @property + def url(self): + return 'http://localhost/' + + @property + def host(self): + return 'localhost' + + @property + def headers(self): + return {'Content-Type': 'application/json'} + + + class TestFunc(unittest.TestCase): + # noinspection PyTypeChecker + def test_func(self): + result, code = func.main(Context(DummyRequest('flame,confused'))) + expected = """{"flame": "('fire', '🔥')", "confused": "('confused_face', '😕')"}""" + self.assertEqual(expected, result) + self.assertEqual(code, 200) + + if __name__ == "__main__": + unittest.main() + ``` + +1. Use `pip3` to install the dependencies listed in the `requirements.txt` file: + + ```command + pip3 install -r ~/get-emojis/requirements.txt + ``` + +1. Use the `python3` command to run the `test_func.py` file and test the invocation of your function: + + ```command + python3 ~/get-emojis/test_func.py + ``` + + A successful test should produce the following output: + + ```output + Received request + GET http://localhost/ localhost + Content-Type: application/json + URL Query String: + {"descriptions": "flame,confused"} + + + . + ---------------------------------------------------------------------- + Ran 1 test in 0.395s + + OK + ``` + +Once the code behaves as expected, you can test the function locally by packaging it in a Docker container using `func invoke` to run it. This approach is handled completely through Docker, without the need for a local Kubernetes cluster. + +After local testing, you may want to optimize the function's image size by removing any redundant dependencies to improve resource utilization. Deploy your function to a staging environment (a Kubernetes cluster with Knative installed) using `func deploy`. In the staging environment, you can conduct integration, regression, and stress testing. + +{{< note >}} +If your function interacts with external services or the Kubernetes API server, you should *"mock"* these dependencies. Mocking, or simulating external services or components that a function interacts with, allows you to isolate a specific function or piece of code to ensure it behaves correctly. +{{< /note >}} + +See **More Information** below for resources to help you get started with migrating AWS Lambda functions to Knative functions on the Linode Kubernetes Engine (LKE). \ No newline at end of file