I am trying to deploy microservices to AWS ECS following this example repo. Here, a load balancer is utilized for networking between different docker services. I have adjusted the cloudformation templates to my needs and have only deployed one service yet, the webserver. I want public access to the web interface and add other services this service is talking to subsequently. However, I currently struggle to get the webserver going using the URL of the load balancer. If I go directly to the EC2 instance using the public IP, I get access to the interface. However, if I go to the load balancer DNS, I get 503 Service Temporarily Unavailable. I have checked the AWS docs, but the webservice target group shows a registered target (the EC2 instance) with status healthy. What am I missing?
Parameters:
EnvironmentName:
Description: An environment name that will be prefixed to resource names
Type: String
VPC:
Type: AWS::EC2::VPC::Id
Description: Choose which VPC the Application Load Balancer should be deployed to
Subnets:
Description: Choose which subnets the Application Load Balancer should be deployed to
Type: AWS::EC2::Subnet::Id
PublicSubnet:
Description: Choose which public subnet the EC2 instance should be deployed to
Type: AWS::EC2::Subnet::Id
Resources:
LoadBalancerSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupName: !Sub ${EnvironmentName}-loadbalancer
GroupDescription: Access to the load balancer that sits in front of ECS
VpcId: !Ref VPC
SecurityGroupIngress:
# Allow access from anywhere to our ECS services
- CidrIp: 0.0.0.0/0
IpProtocol: -1
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-LoadBalancers
LoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Ref EnvironmentName
Subnets:
- !Ref Subnets
SecurityGroups:
- !Ref LoadBalancerSecurityGroup
Tags:
- Key: Name
Value: !Ref EnvironmentName
LoadBalancerListener:
Type: AWS::ElasticLoadBalancingV2::Listener
Properties:
LoadBalancerArn: !Ref LoadBalancer
Port: 80
Protocol: HTTP
DefaultActions:
- Type: forward
TargetGroupArn: !Ref DefaultTargetGroup
DefaultTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${EnvironmentName}-default
VpcId: !Ref VPC
Port: 80
Protocol: HTTP
ECSHostSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupName: !Sub ${EnvironmentName}-ecs-hosts
GroupDescription: Access to the ECS hosts and the tasks/containers that run on them
VpcId: !Ref VPC
SecurityGroupIngress:
# Only allow inbound access to ECS from the ELB
- SourceSecurityGroupId: !Ref LoadBalancerSecurityGroup
IpProtocol: -1
- IpProtocol: tcp
FromPort: 22
ToPort: 22
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-ECS-Hosts
ECSCluster:
Type: AWS::ECS::Cluster
Properties:
ClusterName: !Ref EnvironmentName
ECSRole:
Type: AWS::IAM::Role
Properties:
Path: /
RoleName: !Sub ${EnvironmentName}-ecs-role
AssumeRolePolicyDocument:
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: 'sts:AssumeRole'
ManagedPolicyArns:
- 'arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role'
- 'arn:aws:iam::aws:policy/service-role/AmazonEC2RoleforSSM'
- 'arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy'
ECSInstanceProfile:
Type: AWS::IAM::InstanceProfile
Properties:
Path: /
Roles:
- !Ref ECSRole
EC2Webserver:
Type: AWS::EC2::Instance
Properties:
AvailabilityZone: eu-central-1a
ImageId: !Ref ECSAMI
InstanceType: !Ref InstanceType
IamInstanceProfile: !Ref ECSInstanceProfile
UserData:
Fn::Base64:
!Sub |
#!/bin/bash
# Add to cluster:
echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
echo ECS_ENABLE_AWSLOGS_EXECUTIONROLE_OVERRIDE=true >> /etc/ecs/ecs.config
SecurityGroupIds:
- !Ref ECSHostSecurityGroup
SubnetId: !Ref PublicSubnet
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}
Service:
Type: AWS::ECS::Service
DependsOn: ListenerRule
Properties:
Cluster: !Ref Cluster
Role: !Ref ServiceRole
DesiredCount: !Ref DesiredCount
TaskDefinition: !Ref TaskDefinitionWebserver
LoadBalancers:
- ContainerName: !Sub ${EnvironmentName}-webserver
ContainerPort: 8080
TargetGroupArn: !Ref TargetGroup
TaskDefinitionWebserver:
Type: AWS::ECS::TaskDefinition
Properties:
Family: !Sub ${EnvironmentName}-webserver
ContainerDefinitions:
- Name: !Sub ${EnvironmentName}-webserver
Essential: true
Image: !Ref Image
Memory: 512
PortMappings:
- ContainerPort: 8080
HostPort: 80
TargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${EnvironmentName}-webserver
VpcId: !Ref VPC
Port: 80
Protocol: HTTP
Matcher:
HttpCode: 200-299
HealthCheckIntervalSeconds: 30
HealthCheckPath: /health
HealthCheckProtocol: HTTP
HealthCheckTimeoutSeconds: 10
HealthyThresholdCount: 5
ListenerRule:
Type: AWS::ElasticLoadBalancingV2::ListenerRule
Properties:
ListenerArn: !Ref LoadBalancerListener
Priority: 1
Conditions:
- Field: path-pattern
Values:
- /
Actions:
- TargetGroupArn: !Ref TargetGroup
Type: forward
ServiceRole:
Type: AWS::IAM::Role
Properties:
RoleName: !Sub ecs-service-${AWS::StackName}
Path: /
AssumeRolePolicyDocument: |
{
"Statement": [{
"Effect": "Allow",
"Principal": { "Service": [ "ecs.amazonaws.com" ]},
"Action": [ "sts:AssumeRole" ]
}]
}
Policies:
- PolicyName: !Sub ecs-service-${AWS::StackName}
PolicyDocument:
{
"Version": "2012-10-17",
"Statement":
[
{
"Effect": "Allow",
"Action":
[
"ec2:AuthorizeSecurityGroupIngress",
"ec2:Describe*",
"elasticloadbalancing:DeregisterInstancesFromLoadBalancer",
"elasticloadbalancing:Describe*",
"elasticloadbalancing:RegisterInstancesWithLoadBalancer",
"elasticloadbalancing:DeregisterTargets",
"elasticloadbalancing:DescribeTargetGroups",
"elasticloadbalancing:DescribeTargetHealth",
"elasticloadbalancing:RegisterTargets"
],
"Resource": "*"
}
]
}
Outputs:
WebsiteServiceUrl:
Description: The URL endpoint for the website service
Value: !Join ["", [!GetAtt LoadBalancer.DNSName, "/"]]
Thanks everyone! I finally figured it out, what I had to do was adjusting the path as my service redirects on /. So I only changed the listener rule using a wildcard:
ListenerRule:
Type: AWS::ElasticLoadBalancingV2::ListenerRule
Properties:
ListenerArn: !Ref LoadBalancerListener
Priority: 1
Conditions:
- Field: path-pattern
Values:
- [/*]
Actions:
- TargetGroupArn: !Ref TargetGroup
Type: forward