Friday, 4 September 2020

Getting started with Amazon Managed Streaming for Apache Kafka (Amazon MSK)

Amazon MSK is a fully managed service that enables you to build and run applications that use Apache Kafka to process streaming data. ## Create MSK Cluster - [Via Console](https://docs.aws.amazon.com/msk/latest/developerguide/getting-started.html) - [Via Amazon CDK](https://github.com/wingkwong/aws-playground/tree/master/msk/cdk) ## Create a Client Machine - Create an EC2 instance to create a topic that produces and consumes data as you cannot access Amazon MSK directly from a local machine. The brokers and zookeeper connect string are private. - Download [Apache Kafka](https://kafka.apache.org/downloads) - Upload to ``~/`` and unzip it. Example: ``~/kafka_2.13-2.6.0/`` - Install ``python3`` by running ``sudo yum install -y python3`` - Install ``java`` by running ``sudo yum install java-1.8.0-openjdk`` - Install ``kafka-python`` by running ``sudo pip install kafka-python`` ## Create Kafka Topic Connect to the client machine ```bash #!/bin/sh zookeeperConnectString="<YOUR_ZOOKEEPER_CONNECT_STRING>" # retrieved from "View Client Information" in Amazon MSK Console kafka_topic="<YOUR_KAFKA_TOPIC>" replication_factor=1 partitions=1 # Change directory to Kafka bin cd ~/kafka_2.13-2.6.0/bin/ # Execute kafka-topics.sh ./kafka-topics.sh --create --zookeeper $zookeeperConnectString --replication-factor $replication_factor --partitions $partitions --topic $kafka_topic ``` ## Produce Data ```py from time import sleep from json import dumps from kafka import KafkaProducer # Define Amazon MSK Brokers brokers=['<YOUR_MSK_BROKER_1>:9092', '<YOUR_MSK_BROKER_2>:9092'] # Define Kafka topic to be produced to kafka_topic='<YOUR_KAFKA_TOPIC>' # A Kafka client that publishes records to the Kafka cluster producer = KafkaProducer(bootstrap_servers=brokers, value_serializer=lambda x: dumps(x).encode('utf-8')) # To produce 1000 numbers from 0 to 999 for num in range(1000): data = {'number' : num} producer.send(kafka_topic, value=data) sleep(1) ``` ## Consume Data ```py from kafka import KafkaConsumer from json import loads # Define Amazon MSK Brokers brokers=['<YOUR_MSK_BROKER_1>:9092', '<YOUR_MSK_BROKER_2>:9092'] # Define Kafka topic to be consumed from kafka_topic='<YOUR_KAFKA_TOPIC>' # A Kafka client that consumes records from a Kafka cluster consumer = KafkaConsumer( kafka_topic, bootstrap_servers=brokers, auto_offset_reset='earliest', enable_auto_commit=True, group_id='my-group', value_deserializer=lambda x: loads(x.decode('utf-8'))) for message in consumer: message = message.value print('{}'.format(message)) ``` ## Common Issues Thrown the following error while creating a Kafka topic ``` Exception in thread "main" kafka.zookeeper.ZooKeeperClientTimeoutException: Timed out waiting for connection while in state: CONNECTING at kafka.zookeeper.ZooKeeperClient.waitUntilConnected(ZooKeeperClient.scala:262) at kafka.zookeeper.ZooKeeperClient.<init>(ZooKeeperClient.scala:119) at kafka.zk.KafkaZkClient$.apply(KafkaZkClient.scala:1865) at kafka.admin.TopicCommand$ZookeeperTopicService$.apply(TopicCommand.scala:360) at kafka.admin.TopicCommand$.main(TopicCommand.scala:55) at kafka.admin.TopicCommand.main(TopicCommand.scala) ``` Solution: Check Securty Group to make sure that the inbound is allowed.

Wednesday, 2 September 2020

Building a CI/CD pipeline for a SAM application written in Go

This tutorial shows how to build a CI/CD Pipeline for a SAM Application written in Go with CodeCommit, CodeBuild, CodePipeline, CloudFormation and the AWS CDK. ## Prerequisites You need to have an AWS account and installed and configured AWS CLI and Go. ## Initialize The Hello World SAM project - Run ``sam init`` - Type 1 to select AWS Quick Start Templates - Choose ``go1.x`` for runtime - Leave default ``sam-app`` for project name - Type 1 to select the Hello World Example - Verify if ``sam-app`` have been created When deploying this project, it will create an API Gateway, a Lambda function and a IAM Role. They are defined in ``template.yaml``. ``` HelloWorldAPI: Description: "API Gateway endpoint URL for Prod environment for First Function" Value: !Sub "https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/Prod/hello/" HelloWorldFunction: Description: "First Lambda Function ARN" Value: !GetAtt HelloWorldFunction.Arn HelloWorldFunctionIamRole: Description: "Implicit IAM Role created for Hello World function" Value: !GetAtt HelloWorldFunctionRole.Arn ``` The Lambda function simply prints out ``Hello World``. ``` func handler(request events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) { return events.APIGatewayProxyResponse{ Body: "Hello World!", StatusCode: 200, }, nil } ``` ## Run SAM Application Locally SAM allows your to run your serverless application locally for your development and testing by running the following command. The default local port number is ``3000``. If you are running your app on Cloud9 workspace, you need to override it with ``--port`` as Cloud 9 only support 8080, 8081 or 8082 in the local browser. ``` sam local start-api --port 8080 ``` You should see ``` Mounting HelloWorldFunction at http://127.0.0.1:8080/hello [GET] You can now browse to the above endpoints to invoke your functions. You do not need to restart/reload SAM CLI while working on your functions, changes will be reflected instantly/automatically. You only need to restart SAM CLI if you update your AWS SAM template * Running on http://127.0.0.1:8080/ (Press CTRL+C to quit) ``` Let's verify it ``` curl http://127.0.0.1:8080/hello ``` You should see ``` Hello World ``` ## Deploy to AWS Run ``sam build`` to build the project. ``` sam build ``` A hidden directory has been created by SAM ![image](https://user-images.githubusercontent.com/35857179/91292239-d0285100-e7c8-11ea-9618-526ae0a2cb3b.png) Run ``sam deploy`` to deploy your application. SAM will createa a CloudFormation stack and you can have a guided interactive mode by specifying ``--guided`` parameter. ``` sam deploy --guided ``` Configuring SAM deploy ``` Looking for samconfig.toml : Not found Setting default arguments for 'sam deploy' ========================================= Stack Name [sam-app]: AWS Region [us-east-1]: ap-southeast-1 #Shows you resources changes to be deployed and require a 'Y' to initiate deploy Confirm changes before deploy [y/N]: y #SAM needs permission to be able to create roles to connect to the resources in your template Allow SAM CLI IAM role creation [Y/n]: Y HelloWorldFunction may not have authorization defined, Is this okay? [y/N]: Y Save arguments to samconfig.toml [Y/n]: Y Looking for resources needed for deployment: Not found. Creating the required resources... Successfully created! Managed S3 bucket: aws-sam-cli-managed-default-samclisourcebucket-542w25h26du5 A different default S3 bucket can be set in samconfig.toml Saved arguments to config file Running 'sam deploy' for future deployments will use the parameters saved above. The above parameters can be changed by modifying samconfig.toml Learn more about samconfig.toml syntax at https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-config.html Uploading to sam-app/9a42d6084bb2aaa2f7eaf7b2201e115a 5094701 / 5094701.0 (100.00%) ``` Deploying with following values ``` Stack name : sam-app Region : ap-southeast-1 Confirm changeset : True Deployment s3 bucket : aws-sam-cli-managed-default-samclisourcebucket-542w25h26du5 Capabilities : ["CAPABILITY_IAM"] Parameter overrides : {} ``` Initiating deployment ``` HelloWorldFunction may not have authorization defined. Uploading to sam-app/21a49766581b625811536c904121d4ba.template 1154 / 1154.0 (100.00%) Waiting for changeset to be created.. CloudFormation stack changeset --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Operation LogicalResourceId ResourceType --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + Add HelloWorldFunctionCatchAllPermissionProd AWS::Lambda::Permission + Add HelloWorldFunctionRole AWS::IAM::Role + Add HelloWorldFunction AWS::Lambda::Function + Add ServerlessRestApiDeployment47fc2d5f9d AWS::ApiGateway::Deployment + Add ServerlessRestApiProdStage AWS::ApiGateway::Stage + Add ServerlessRestApi AWS::ApiGateway::RestApi --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Changeset created successfully. arn:aws:cloudformation:ap-southeast-1:XXXXXXXXXXX:changeSet/samcli-deploy1598436540/ea868c52-9c9a-4d27-a008-ef6157f65b9b ``` Previewing CloudFormation changeset before deployment ``` Deploy this changeset? [y/N]: y 2020-08-26 18:09:42 - Waiting for stack create/update to complete CloudFormation events from changeset ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ResourceStatus ResourceType LogicalResourceId ResourceStatusReason ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- CREATE_IN_PROGRESS AWS::IAM::Role HelloWorldFunctionRole - CREATE_IN_PROGRESS AWS::IAM::Role HelloWorldFunctionRole Resource creation Initiated CREATE_COMPLETE AWS::IAM::Role HelloWorldFunctionRole - CREATE_IN_PROGRESS AWS::Lambda::Function HelloWorldFunction - CREATE_IN_PROGRESS AWS::Lambda::Function HelloWorldFunction Resource creation Initiated CREATE_COMPLETE AWS::Lambda::Function HelloWorldFunction - CREATE_IN_PROGRESS AWS::ApiGateway::RestApi ServerlessRestApi - CREATE_IN_PROGRESS AWS::ApiGateway::RestApi ServerlessRestApi Resource creation Initiated CREATE_COMPLETE AWS::ApiGateway::RestApi ServerlessRestApi - CREATE_IN_PROGRESS AWS::Lambda::Permission HelloWorldFunctionCatchAllPermissionProd Resource creation Initiated CREATE_IN_PROGRESS AWS::ApiGateway::Deployment ServerlessRestApiDeployment47fc2d5f9d - CREATE_IN_PROGRESS AWS::Lambda::Permission HelloWorldFunctionCatchAllPermissionProd - CREATE_IN_PROGRESS AWS::ApiGateway::Deployment ServerlessRestApiDeployment47fc2d5f9d Resource creation Initiated CREATE_COMPLETE AWS::ApiGateway::Deployment ServerlessRestApiDeployment47fc2d5f9d - CREATE_IN_PROGRESS AWS::ApiGateway::Stage ServerlessRestApiProdStage - CREATE_IN_PROGRESS AWS::ApiGateway::Stage ServerlessRestApiProdStage Resource creation Initiated CREATE_COMPLETE AWS::ApiGateway::Stage ServerlessRestApiProdStage - CREATE_COMPLETE AWS::Lambda::Permission HelloWorldFunctionCatchAllPermissionProd - CREATE_COMPLETE AWS::CloudFormation::Stack sam-app - ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- CloudFormation outputs from deployed stack ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Outputs ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Key HelloWorldFunctionIamRole Description Implicit IAM Role created for Hello World function Value arn:aws:iam::XXXXXXXXXXX:role/sam-app-HelloWorldFunctionRole-CXSDBGUHPMFS Key HelloWorldAPI Description API Gateway endpoint URL for Prod environment for First Function Value https://yh1q5tcsqg.execute-api.ap-southeast-1.amazonaws.com/Prod/hello/ Key HelloWorldFunction Description First Lambda Function ARN Value arn:aws:lambda:ap-southeast-1:XXXXXXXXXXX:function:sam-app-HelloWorldFunction-13LO5HE0Y7BKS ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Successfully created/updated stack - sam-app in ap-southeast-1 ``` ![image](https://user-images.githubusercontent.com/35857179/91291849-3c568500-e7c8-11ea-911c-a89772e7e86a.png) To verifiy it, click the HelloWorldApi Value in sam-app Output. ![image](https://user-images.githubusercontent.com/35857179/91868928-dd04e300-eca7-11ea-81e8-277d345ad5a4.png) ## Building the pipeline With a continous delivery pipeline using AWS Code Pipeline, we can automate the build, package, and deploy commands. Other services will be used such as CodeCommit, CloudFormation and the AWS CDK. The general flow would be like ``` Developer -- pushes changes --> Git Repository -- build --> deploy --> AWS ``` ## Setting up CodeCommit Let's create a CodeCommit repository ``` aws codecommit create-repository --repository-name sam-app ``` You should see the following output ```json { "repositoryMetadata": { "accountId": "XXXXXXXXXXXX", "repositoryId": "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX", "repositoryName": "sam-app", "lastModifiedDate": "2020-08-26T18:26:36.257000+08:00", "creationDate": "2020-08-26T18:26:36.257000+08:00", "cloneUrlHttp": "https://git-codecommit.ap-southeast-1.amazonaws.com/v1/repos/sam-app", "cloneUrlSsh": "ssh://git-codecommit.ap-southeast-1.amazonaws.com/v1/repos/sam-app", "Arn": "arn:aws:codecommit:ap-southeast-1:XXXXXXXXXXXX:sam-app" } } ``` To configurate git credentials ``` git config --global credential.helper '!aws codecommit credential-helper $@' git config --global credential.UseHttpPath true git config --global user.name "wingkwong" git config --global user.email "wingkwong.code@gmail.com" ``` Go to the root directory of your SAM project and run ``` cd ./sam-app git init git add . git commit -m "Initial commit" ``` Setup Git origin ``` git remote add origin ``` Push the code to origin ``` git push -u origin master ``` You should see ``` Counting objects: 17, done. Delta compression using up to 4 threads. Compressing objects: 100% (13/13), done. Writing objects: 100% (17/17), 4.86 MiB | 1.55 MiB/s, done. Total 17 (delta 0), reused 0 (delta 0) To https://git-codecommit.ap-southeast-1.amazonaws.com/v1/repos/sam-app * [new branch] master -> master Branch 'master' set up to track remote branch 'master' from 'origin'. ``` ## Setting up CodePipline We will use Amazon CDK to provision the pipeline. ### Install CDK ``` npm install -g aws-cdk ``` ### Initialize the project ``` cdk init --language typescript ``` ### To bulid and deploy ``` npm run build cdk deploy ``` You should see ``PipelineStack`` has been created Go to AWS Console -> Developer Tools -> CodePipeline -> Pipelines ![image](https://user-images.githubusercontent.com/35857179/91635192-ffd59400-ea28-11ea-96ae-406de4650a89.png) ## Clean up ``` cdk destroy PipelineStack ``` ``` Are you sure you want to delete: PipelineStack (y/n)? y PipelineStack: destroying... 11:21:26 PM | DELETE_IN_PROGRESS | AWS::CloudFormation::Stack | PipelineStack 11:22:34 PM | DELETE_IN_PROGRESS | AWS::IAM::Role | Pipeline/Dev/Creat...PipelineActionRole 11:22:34 PM | DELETE_IN_PROGRESS | AWS::IAM::Role | Pipeline/Build/Bui...PipelineActionRole 11:22:34 PM | DELETE_IN_PROGRESS | AWS::IAM::Role | Build/Role ✅ PipelineStack: destroyed ```

Wednesday, 26 August 2020

Project Euler #001 - Multiples of 3 and 5

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3,5,6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below N. Sample Input ``` 2 10 100 ``` Sample Output ``` 23 2318 ``` To sum from 1 to i, it is ``` s = 1 + 2 + 3... + (i - 1) + i ``` if you reverse the order ``` s = 1 + 2 + 3... + (i - 1) + i s = i + (i - 1) + (i - 2) + ... + 2 + 1 ``` summing each value, we got ``` 2 * s = (i + 1) + (i + 1) + ...(i + 1) + (i + 1) ``` and there are ``i`` ``(i + 1)`` in above formula ``` 2 * s = i * (i + 1) ``` at the end, we got ``` s = i * (i + 1) / 2 ``` We can use ``s = i(i + 1) / 2`` to caculate the sum from 1 to ``i``. However, the question just needs us to calculate the sum of the multiples of 3 or 5. Take 3 as an example ``` s = 3 + 6 + 9 + ... + 3i s = 3(1 + 2 + 3 + ... + i) ``` We know that ``1 + 2 + 3 + ... + i`` can be calculated using ``s = i * (i + 1) / 2``. Therefore, we now know ``` s = 3 * (1 + 2 + 3 + ... + i) s = 3 * (i * (i + 1) / 2) ``` where ``` 3 * i <= n i <= n / 3 ``` it becomes ``` s = n * ((n / k)((n / k) + 1) / 2) ``` The question states that it only requires the multiples of K below N, that means it does not include N, hence we should substract N from 1. However, if we sum up multiples of 3 and multiples of 5, we can get duplicate values, i.e. 15 in below example ``` multiples of 3: 3, 6, 9, 15, 18... multiples of 5: 5, 10, 15, 20,... ``` Hence, we need to subtract the series of their least common multiple (LCM) which is 15. The final answer is ``` S(3) + S(5) - S(15) ``` Final Solution: ```cpp ll t,i,x; ll s(ll n,ll k){ x = n / k; return (k * (x * (x + 1))) / 2; } int main() { FAST_INP; cin >> t; TC(t){ cin >> i; cout << s(i - 1, 3) + s(i - 1, 5) - s(i - 1, 15) << "\n"; } return 0; } ```

Friday, 14 August 2020

Develop, release and operate Container Apps on AWS with the AWS Copilot CLI

Originally Copilot was called Amazon ECS CLI v2. 

The AWS Copilot CLI is a tool for developers to create, release and manage production ready containerized applications on Amazon ECS and AWS Fargate. From getting started, pushing to a test environment and releasing to production, Copilot helps you through the entire life of your app development.

In short, you can develop, release and operate Container Apps on AWS with a few commands.

![image](https://user-images.githubusercontent.com/35857179/90715223-2fbfc180-e2dc-11ea-923a-f0807146ca61.png)

## Prerequisites

Before using Copilot, make sure you have installed AWS command line tool and setup your aws credentials. To do that, you can run ``aws configure`` to perform your setup. The region for this demonstration is ``ap-southeast-1``. 

After the configuration setup, you can run the below command to verify

```bash
aws sts get-caller-identity
```

## Install

```
curl -Lo /usr/local/bin/copilot https://github.com/aws/copilot-cli/releases/download/v0.1.0/copilot-darwin-v0.1.0 &&
chmod +x /usr/local/bin/copilot &&
copilot --help
```

or through Homebrew

```
brew install aws/tap/copilot-cli
```

## Getting started

Run 

```
copilot
```

to see the commands

```
👩‍✈️ Launch and manage applications on Amazon ECS and AWS Fargate.

Commands 
  Getting Started 🌱
    init        Create a new ECS application.
    docs        Open the copilot docs.
 
  Develop ✨
    app         Commands for applications.
                Applications are a collection of services and environments.

    env         Commands for environments.
                Environments are deployment stages shared between services.

    svc         Commands for services.
                Services are long-running Amazon ECS services.
 
  Release 🚀
    pipeline    Commands for pipelines.
                Continuous delivery pipelines to release services.

    deploy      Deploy your service.
 
  Settings ⚙️
    version     Print the version number.
    completion  Output shell completion code.

Flags
  -h, --help      help for copilot
  -v, --version   version for copilot

Examples
  Displays the help menu for the "init" command.
  `$ copilot init --help`
```

## Init

Copilot will locate the Dockerfile automatically and ask you several questions. After that, it will create a new application containing your service(s).

A sample Dockerfile

```dockerfile
FROM nginx:alpine
EXPOSE 80
COPY . /usr/share/nginx/html
```

Run 

```
copilot init
```

```
Application name: hello-world
Service type: Load Balanced Web Service
Service name: copilot-lb
Dockerfile: ./Dockerfile
Ok great, we'll set up a Load Balanced Web Service named copilot-lb in application hello-world listening on port 80.

✔ Created the infrastructure to manage services under application hello-world.

✔ Wrote the manifest for service copilot-lb at ../copilot-lb/manifest.yml
Your manifest contains configurations like your container size and port (:80).

✔ Created ECR repositories for service copilot-lb.

All right, you're all set for local development.
Deploy: Yes

✔ Created the infrastructure for the test environment.
- Virtual private cloud on 2 availability zones to hold your services     [Complete]
- Virtual private cloud on 2 availability zones to hold your services     [Complete]
  - Internet gateway to connect the network to the internet               [Complete]
  - Public subnets for internet facing services                           [Complete]
  - Private subnets for services that can't be reached from the internet  [Complete]
  - Routing tables for services to talk with each other                   [Complete]
- ECS Cluster to hold your services                                       [Complete]
- Application load balancer to distribute traffic                         [Complete]
✔ Linked account XXXXXXXXXXXX and region ap-southeast-1 to application hello-world.
```

You should be able to see the link at the end. 

Click the link and verify that a simple nginx app is up and running 

![image](https://user-images.githubusercontent.com/35857179/90713597-43692900-e2d8-11ea-8c2f-3caf73e49a28.png)

Go to ECS and you should see a cluster has been provisioned

![image](https://user-images.githubusercontent.com/35857179/90713396-cd64c200-e2d7-11ea-9bd3-a66f86360d2b.png)

You can also take a look at ECS - Task Definition / ECR / EC2 - Load Balancer

## Logs

Copilot provides ``svc logs`` to allow users to check the service logs more easily. You can stream the logs or display the logs within a specfic timeslot

```
  -a, --app string          Name of the application.
      --end-time string     Optional. Only return logs before a specific date (RFC3339).
                            Defaults to all logs. Only one of end-time / follow may be used.
  -e, --env string          Name of the environment.
      --follow              Optional. Specifies if the logs should be streamed.
  -h, --help                help for logs
      --json                Optional. Outputs in JSON format.
      --limit int           Optional. The maximum number of log events returned. (default 10)
  -n, --name string         Name of the service.
      --since duration      Optional. Only return logs newer than a relative duration like 5s, 2m, or 3h.
                            Defaults to all logs. Only one of start-time / since may be used.
      --start-time string   Optional. Only return logs after a specific date (RFC3339).
                            Defaults to all logs. Only one of start-time / since may be used.
```

To stream the logs

```
copilot svc logs --follow
```

To display the logs within a specfic timeslot 

```
copilot svc logs --start-time 2006-01-02T15:04:05+00:00 --end-time 2006-01-02T15:05:05+00:00
```

## Deploy

The application was deployed to the testing environment, which is a single small container to Fargate. It is only for development purposes. 

To deploy in production, run the following command to create a new environment

```
copilot env init
```

Update the manifest file to tell Copilot the application is going to be deployed to production

```
environments:
  production:
    count: 2
    cpu: 1024
    memory: 2048
```

Copilot will create the infrastructure fro the production environment 

```
What is your environment's name? prod
Which named profile should we use to create prod? default
✔ Created the infrastructure for the prod environment.
- Virtual private cloud on 2 availability zones to hold your services     [Complete]
- Virtual private cloud on 2 availability zones to hold your services     [Complete]
  - Internet gateway to connect the network to the internet               [Complete]
  - Public subnets for internet facing services                           [Complete]
  - Private subnets for services that can't be reached from the internet  [Complete]
  - Routing tables for services to talk with each other                   [Complete]
- ECS Cluster to hold your services                                       [Complete]
- Application load balancer to distribute traffic                         [Complete]
✔ Linked account XXXXXXXXXXXX and region ap-southeast-1 to application hello-world.

✔ Created environment prod in region ap-southeast-1 under application hello-world.
```

Deploy your service to production

```
copilot svc deploy --env production
```

## Clean up

```
copilot env list
```

I got 

```
test
prod
```

Force delete the application with environments "test" and "prod"

```
copilot app delete --yes --env-profiles test=default,prod=prod-profile
```

## Conclusion

Copilot can help you to deploy your service containerized to production with a few commands. What you need is just Copilot and Dockerfile. 

Copilot is still in beta. Some services like provisioning storage are not supported yet. (As of 20/08/2020)

## For more

- https://github.com/aws/copilot-cli


Monday, 10 August 2020

Getting Started with Azure Databricks

## Sample Cluster Setup

```json
{
    "num_workers": 5,
    "cluster_name": "Databricks-playground",
    "spark_version": "6.5.x-scala2.11",
    "spark_conf": {
        "spark.dynamicAllocation.enabled": "true",
        "spark.shuffle.compress": "true",
        "spark.shuffle.spill.compress": "true",
        "spark.executor.memory": "7849M",
        "spark.sql.shuffle.partitions": "1024",
        "spark.network.timeout": "600s",
        "spark.executor.instances": "0",
        "spark.driver.memory": "7849M",
        "spark.dynamicAllocation.executorIdleTimeout": "600s"
    },
    "node_type_id": "Standard_F8s",
    "driver_node_type_id": "Standard_F8s",
    "ssh_public_keys": [],
    "custom_tags": {},
    "cluster_log_conf": {
        "dbfs": {
            "destination": "dbfs:/cluster-logs"
        }
    },
    "spark_env_vars": {
        "PYSPARK_PYTHON": "/databricks/python3/bin/python3"
    },
    "autotermination_minutes": 0,
    "init_scripts": []
}
```

## Common commands

List the directory in DBFS

```
%fs ls 
```

Create a directory in DBFS

```
%fs mkdirs src
```

Copy files from src to dist in DBFS

```
%fs cp -r dbfs:/src dbfs:/dist
```

## Setup Mount Point for Blob Storage

Using an old driver called WASB 

### Create Secret Scope

By default, scopes are created with MANAGE permission for the user who created the scope. If your account does not have the Premium plan (or, for customers who subscribed to Databricks before March 3, 2020, the Operational Security package), you must override that default and explicitly grant the MANAGE permission to “users” (all users) when you create the scope

```
databricks secrets create-scope --scope  --initial-manage-principal users
```

To verify 

```
databricks secrets list-scopes
```

### Create Secret 
```
databricks secrets put --scope  --key  --string-value 
```

The value of  can be retrieved from Storage Account -> Settings -> Access Keys

### Create Mount Point

```python
dbutils.fs.mount(
  source = "wasbs://@.blob.core.windows.net",
  mount_point = "/mnt/",
  extra_configs = {"":dbutils.secrets.get(scope = "", key = "")}
)
```

To verify in Databricks Notebook

```python
%fs dbfs:/mnt/
```

## Setup Mount Point for ADLS Gen 2

Requiring the following items

- ``application-id``: An ID that uniquely identifies the application.
- ``directory-id``: An ID that uniquely identifies the Azure AD instance.
- ``storage-account-name``: The name of the storage account.
- ``service-credential``: A string that the application uses to prove its identity.

### Create Mount Point 

```python
configs = {"fs.azure.account.auth.type": "OAuth",
           "fs.azure.account.oauth.provider.type": "org.apache.hadoop.fs.azurebfs.oauth2.ClientCredsTokenProvider",
           "fs.azure.account.oauth2.client.id": "",
           "fs.azure.account.oauth2.client.secret": dbutils.secrets.get(scope="",key=""),
           "fs.azure.account.oauth2.client.endpoint": "https://login.microsoftonline.com//oauth2/token"}

# Optionally, you can add  to the source URI of your mount point.
dbutils.fs.mount(
  source = "abfss://@.dfs.core.windows.net/",
  mount_point = "/mnt/",
  extra_configs = configs)
```

## Performance Tuning 

- Use Ganglia to see the metrics and gain insights

- Use Spark 3.0 if your application contians lots of joining logic
    - Adaptive Query Execution to speed up Spark SQL at runtime 
    - Ref: https://databricks.com/blog/2020/05/29/adaptive-query-execution-speeding-up-spark-sql-at-runtime.html
    - Simply enable it by setting ``spark.sql.adaptive.enabled`` to ``true``

## Common issues

### No output files written in storage 

Probably it is out of memory. Try adjust the hardware settings. 

### Clusters settings not apply to jobs 

Make sure the cluster is interactive or automated. Interactive one is for notebooks. If you create a job, you should be able to modify the cluster settings in the job creation page. 

### Spark conf is not supported via cluster settings for spark-submit task

Self-explanatory 

```
{"error_code":"INVALID_PARAMETER_VALUE","message":"Spark conf is not supported via cluster settings for spark-submit task. Please use spark-submit parameters to set spark conf."}
```

### Custom Dependencies cannot be found

Suppose your package is located in ``/dbfs/databricks/driver/jobs/``, add the following code in your entry point.

Python Example:

```python
import sys
sys.path.append("/dbfs/databricks/driver/jobs/")
```


## References:

- [Databricks File System (DBFS)](https://docs.databricks.com/data/databricks-file-system.html)
- [Create a Databricks-backed secret scope](https://docs.databricks.com/security/secrets/secret-scopes.html)
- [Azure Data Lake Storage Gen2](https://docs.microsoft.com/en-us/azure/databricks/data/data-sources/azure/azure-datalake-gen2)

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