AWS AppRunner
Introduction
Containers have been one of the most popular and reliable way to build & deploy services and is only growing more and more. Docker has been most used way to containerize applications. As the demand grows, there are many services that provides deployment using Docker. AWS is not behind either and provides not a few, but actually 17 different ways to run containerized applications. Now it would be really lengthy article if I were to go over about every way we can run a container using AWS and I'm sure you it wouldn't be much useful to anyone either, so I'm just going to keep it short and talk about one particular Service AWS AppRunner. Now before that, let's see some of the popular ways we can run containers on AWS:
- AWS ECS ( Elastic Container Service ): It also divides into 2 sub-categories as:
- ECS Fargate
- ECS with EC2
- AWS EKS ( Managed Kubernetes Service offering from AWS )
- AppRunner ( Of course )
- AWS Lambda ( Lambda is also one of the most popular way of running containers and I love this service as well )
- AWS LightSail
- Good old EC2
I know it's getting exhausting list but if it's not for you and you want the entire catalogue, you can head over to this Link to read further.
ECS vs AppRunner
Now this brings to our next question, why do we need to use a new service to run a freaking container if you already know ECS, well....good question. The answer is, you might not however, let's dive in about the pros and cons and then we can decide what's the best fit:
- AppRunner charges are based on usage and has auto-deploy features, comes with pre-configured load-balancing, HTTPS and auto-scaling. If there are no requests, you'll only be charged for the memory usage ( and even just the memory that app is using while running, not allocated ) no CPU charges, no load-balancer charges.
- It abstracts away all the complexity which we have to deal with while working with ECS. We also don't have to provision an ELB which saves us a fortune if you're running a small app and are worried about it going viral. The AppRunner will auto-scale based on usage and then scale down once the traffic is gone.
So these are the 2 main reasons AppRunner is favored for small scale applications. Once the application starts hitting consistent traffic, you can consider moving it to ECS which will be really easy considering it also runs containers.
The Code
Now, enough talk, where is the code you might ask, well here's the cloudformation for spinning up a AppRunner.
Resources:
AppRunnerRole:
Metadata:
"aws:description": "An IAM Role for App Runner to use on your behalf to pull your image from ECR"
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2008-10-17"
Statement:
- Effect: Allow
Principal:
Service:
- build.apprunner.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/service-role/AWSAppRunnerServicePolicyForECRAccess
InstanceRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Statement:
- Effect: Allow
Principal:
Service: tasks.apprunner.amazonaws.com
Action: "sts:AssumeRole"
Policies:
- PolicyName: AppRunnerServicePolicy
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- "ssm:GetParameters"
Resource:
- !Sub "arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/dev/redis/user"
- Effect: Allow
Action:
- "dynamodb:PutItem"
- "dynamodb:Query"
- "dynamodb:GetItem"
- "dynamodb:UpdateItem"
- "dynamodb:DeleteItem"
- "dynamodb:GetRecords"
Resource:
- !GetAtt MyTable.Arn
- !Sub "${MyTable.Arn}/*"
AppRunnerService:
Type: AWS::AppRunner::Service
Properties:
ServiceName: MyService
InstanceConfiguration:
Cpu: 256
Memory: 512
InstanceRoleArn: !GetAtt InstanceRole.Arn
HealthCheckConfiguration:
Protocol: HTTP
Path: /
SourceConfiguration:
AutoDeploymentsEnabled: false
AuthenticationConfiguration:
AccessRoleArn: !GetAtt AppRunnerRole.Arn
ImageRepository:
ImageRepositoryType: ECR
ImageIdentifier: !Sub "${AWS::AccountId}.dkr.ecr.${AWS::Region}.amazonaws.com/${self:custom.ecr-repo.myimage:myimagetag"
ImageConfiguration:
Port: 8080
RuntimeEnvironmentVariables:
- Name: STAGE
Value: ${self:provider.stagen.${self:provider.stage}}
RuntimeEnvironmentSecrets:
- Name: REDIS_USER
Value: !Sub "arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/dev/redis/user"
Outputs:
AppRunnerServiceUrl:
Value: !GetAtt AppRunnerService.ServiceUrl
Description: The URL of the service