NOTE: This repo contains only the documentation for the private BoltsOps Pro repo code. Original file: https://github.com/boltopspro/asg-elb/blob/master/README.md The docs are publish so they are available for interested customers. For access to the source code, you must be a paying BoltOps Pro subscriber. If are interested, you can contact us at contact@boltops.com or https://www.boltops.com

AutoScaling Instances with ELB CloudFormation Blueprint

This blueprint provisions an ELB and an AutoScaling fleet of instances. This blueprint is useful if you just need a highly available application deployed being a Load Balancer with traditional EC2 instances.

• Template makes use of the flexible AWS::AutoScaling::AutoScalingGroup MixedInstancesPolicy. This allows you to use spot, on-demand, or mixed instance types. For example, you can run 70% spot and 30% on-demand instances. Set OnDemandPercentageAboveBaseCapacity=0 to run all spot instances.
• Several AWS::ElasticLoadBalancingV2::LoadBalancer properties are configurable with Parameters. Additionally, properties that require further customization are configurable with Variables. The blueprint is extremely flexible and configurable for your needs.
• You can use internal, external, application, or network Load Balancers and provision them in private or public subnets.
• You can launch the AutoScaling instances in a Custom VPC and Subnet by configuring VpcId and SubnetId.
• You can customize the UserData script and control the bootstrap process with a @user_data_script variable or with configsets. The httpd is a good starter configset to use for testing.
• You can assign existing Security Groups to the instance or have the blueprint create a managed Security Group.
• You can optionally create a Route53 Record and point it to the ELB dns name.

Usage

1. Add blueprint to Gemfile
2. Configure: configs/asg-elb values
3. Deploy

Add

Add the blueprint to your lono project's Gemfile.

gem "asg-elb", git: "git@github.com:boltopspro/asg-elb.git"

Configure

First you want to configure the configs files. Use lono seed to configure starter values quickly.

lono seed asg-elb

The generated files in config/asg-elb folder look something like this:

configs/asg-elb/
├── params
│   └── development.txt
└── variables
    └── development.rb

Here's an example config with some of the values:

configs/asg-elb/params/development.txt

# Parameter Group: AWS::AutoScaling::AutoScalingGroup
VPCZoneIdentifier=<%= lookup_output("vpc.PrivateAppSubnets") %> # (required)
# MaxSize=8
# MinSize=1

# Parameter Group: AWS::AutoScaling::AutoScalingGroup MixedInstancesPolicy InstancesDistribution
OnDemandPercentageAboveBaseCapacity=0 # 0 means all spot instances, 100 means all on-demand instances. Default is 100
# OnDemandBaseCapacity= # The minimum amount of the Auto Scaling group's capacity that must be fulfilled by On-Demand Instances.
# SpotAllocationStrategy= # lowest-price | capacity-optimized
# SpotInstancePools= # The range is 1 to 20. Higher means more spot pools.

# Parameter Group: AWS::EC2::LaunchTemplate LaunchTemplateData
KeyName=<%= key_pairs(/default/).first %>
# InstanceType=t3.micro

# Parameter Group: AWS::EC2::SecurityGroup
VpcId=<%= lookup_output("vpc.Vpc") %> # (required)

# Parameter Group: AWS::ElasticLoadBalancingV2::LoadBalancer
Subnets=<%= lookup_output("vpc.PrivateAppSubnets") %> # Used for VPCZoneIdentifier of AutoScalingGroup also. # (required)
# Scheme= # internal or internet-facing
# SecurityGroups= # sg-111,sg-222
# Type=application # application # application or network

# Parameter Group: AWS::ElasticLoadBalancingV2::Listener
# CertificateArn= # arn:aws:acm:us-west-2:112233445566:certificate/8d8919ce-a710-4050-976b-b33dbEXAMPLE
# Port=80 # 80
# Protocol=HTTP # HTTP # For Application ELB: HTTP | HTTPS. For Network ELB: TCP_UDP | UDP | TCP | TLS

# Parameter Group: AWS::ElasticLoadBalancingV2::TargetGroup
# HealthCheckPath=

# Parameter Group: AWS::Route53::RecordSet
# DnsName= # my-elb.example.com.
# HostedZoneName= # example.com.

Deploy

Use the lono cfn deploy command to deploy. Example:

lono cfn deploy asg-elb --sure
lono cfn deploy my-app --blueprint asg-elb --sure # different stack name from the blueprint name

Configure: More Details

httpd configset

The httpd will configure, install, and run httpd. This is useful example for testing. Add it with configs, example:

configs/configsets/base.rb:

configset "httpd", resource: "LaunchTemplate"

Adjust IAM Policy

You can adjust and add additional permissions to the IAM policy associated with the instance with: @iam_managed_policy_arns and @iam_policies. Example:

configs/variables/development.rb:

@iam_policies = [
  {
    PolicyName: "extra-policy",
    PolicyDocument: {
      Version: "2012-10-17",
      Statement: [
        {
          Effect: "Allow",
          Action: [
            "events:*",
          ],
          Resource: "*"
        }
      ]
    }
  }
]
@iam_managed_policy_arns = ["arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"]

If you want to override and replace the IAM policies completely, use @iam_managed_policy_arns_replace and @iam_policies_replace.

Changing VPCs

There's a CloudFormation bug where if you change the ELB Subnets, it causes a stack rollback. The workaround is to requires deleting the stack and recreating it. Here's a command to use the same blueprint with a different stack name:

lono cfn deploy asg-elb-2 --blueprint asg-elb

Security Groups: ELB

You can change Security Group ingress rules for the ELB with @elb_security_group_ingress:

@elb_security_group_ingress = [{
  CidrIp: "0.0.0.0/0", # another example: lookup_output("vpc.VpcCidr")
  FromPort: 80,
  IpProtocol: "tcp",
  ToPort: 80,
}]

This whitelist port 80 to the world.

Security Groups: Default ELB -> EC2 Security Group Ingress

By default, AWS::EC2::SecurityGroupIngress rules are created to whitelist the ELB to talk to the EC2 instance on port 80. You can override the ports with the @elb_to_ec2_ports_whitelist variable. Examples:

configs/asg-elb/variables/development.rb:

@elb_to_ec2_ports_whitelist = [80, 443] # Item are ports
# @elb_to_ec2_ports_whitelist = [(80..443)] # Items can be ranges
# @elb_to_ec2_ports_whitelist = (80..443) # Or single range

Security Groups: EC2 Instances

You can change Security Group ingress rules for the EC2 instances @security_group_ingress:

@security_group_ingress = [{
  CidrIp: "0.0.0.0/0", # another example: lookup_output("vpc.VpcCidr")
  FromPort: 22,
  IpProtocol: "tcp",
  ToPort: 22,
}]

This whitelist port 22 to the world.

Route53 DNS Pretty Host Name

You can use HostedZoneId or HostedZoneName to create a pretty endpoint pointing to the ELB DNS. Example:

DnsName=my-instance.example.com.
HostedZoneName=example.com.