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---
AWSTemplateFormatVersion: '2010-09-09'
Description: Creates one Logstash server, two SNMP agents on EC2 instances and a Secret
  in AWS Secrets Manager. **WARNING** This template creates Amazon EC2 instances,
  Amazon CloudWatch custom metrics and related resources. You will be billed for the
  AWS resources used if you create a stack from this template.
Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
      - Label:
          default: Network configuration
        Parameters:
          - MyVPC
          - MySubnet
      - Label:
          default: Amazon EC2 configuration
        Parameters:
          - LogstashInstanceType
          - SNMPInstanceType
          - LatestAmiId
          - RepoLocation
      - Label:
          default: Troubleshooting and connectivity
        Parameters:
          - SSHLocation
          - MyKeyPair
    ParameterLabels:
      MyVPC:
        default: Deployment VPC
      MySubnet:
        default: Deployment subnet with internet access
      LatestAmiId:
        default: Amazon Linux 2 AMI ID
      RepoLocation:
        default: GitHub repository URL
      MyKeyPair:
        default: EC2 Key pair
      LogstashInstanceType:
        default: Instance type for Logstash
      SNMPInstanceType:
        default: Instance type for SNMP agents
      SSHLocation:
        default: SSH Location
Parameters:
  MyVPC:
    Description: Select VPC with internet access
    Type: AWS::EC2::VPC::Id
  MySubnet:
    Description: Select only one subnet with Internet access
    Type: List<AWS::EC2::Subnet::Id>
  LatestAmiId:
    Description: Latest Amazon Linux 2 image from SSM Parameter Store
    Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Default: /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2
  RepoLocation:
    Description: Archive containing configuration and settings
    Type: String
    Default: https://github.com/aws-samples/amazon-cloudwatch-snmp-monitoring-with-logstash/tarball/main
  MyKeyPair:
    Description: Amazon EC2 Key Pair
    Type: AWS::EC2::KeyPair::KeyName
    ConstraintDescription: must be the name of an existing EC2 KeyPair
  LogstashInstanceType:
    AllowedValues:
      - t3.small
      - t3.medium
      - t3.large
      - t3.xlarge
      - t3.2xlarge
    Default: t3.small
    Description: Select instance size based to Logstash JVM size. Keep defaults for
      demo.
    Type: String
  SNMPInstanceType:
    AllowedValues:
      - t3.nano
      - t3.small
      - t3.medium
      - t3.large
      - t3.xlarge
      - t3.2xlarge
    Default: t3.nano
    Description: Amazon EC2 instance type for the SNMP simulator instances
    Type: String
  SSHLocation:
    Description: The IP address range that can be used to SSH to the EC2 instances
    Type: String
    MinLength: '9'
    MaxLength: '18'
    Default: 84.255.0.0/16
    AllowedPattern: (\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/(\d{1,2})
    ConstraintDescription: must be a valid IP CIDR range of the form x.x.x.x/x.
Resources:
  SNMPSecret:
    Type: AWS::SecretsManager::Secret
    Properties:
      Name: SNMPSecret
      Description: my SNMPv3 secret
      GenerateSecretString:
        SecretStringTemplate: '{"username": "readonlyuser"}'
        GenerateStringKey: password
        PasswordLength: 8
        ExcludePunctuation: true
      Tags:
        - Key: AppName
          Value: SNMPdemo
  LogstashRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - sts:AssumeRole
      Path: /
      ManagedPolicyArns:
        - !Sub "arn:${AWS::Partition}:iam::aws:policy/CloudWatchAgentServerPolicy"
  SecretsManagerPolicy:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: SecretsManagerPolicy
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
              - secretsmanager:GetSecretValue
            Resource: !Sub '${SNMPSecret}'
      Roles:
        - !Ref 'LogstashRole'
        - !Ref 'SNMPRole'
  LogstashInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref 'LogstashRole'
  SNMPRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - sts:AssumeRole
      Path: /
  SNMPInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref 'SNMPRole'
  LogstashSG:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Enables SSH access
      VpcId: !Ref 'MyVPC'
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: !Ref 'SSHLocation'
          Description: SSH access locked down to user CIDR
      SecurityGroupEgress:
        - IpProtocol: '-1'
          CidrIp: 0.0.0.0/0
          Description: Allow all outbound traffic
  SNMPSG:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Enables SNMP Poll via port 161 locked down to the Logstash
        server + SSH access
      VpcId: !Ref 'MyVPC'
      SecurityGroupIngress:
        - IpProtocol: udp
          FromPort: 161
          ToPort: 161
          SourceSecurityGroupId: !GetAtt 'LogstashSG.GroupId'
          Description: Allows SNMP poll from Logstash instance
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: !Ref 'SSHLocation'
          Description: SSH access locked down to user CIDR
      SecurityGroupEgress:
        - IpProtocol: '-1'
          CidrIp: 0.0.0.0/0
          Description: Allow all outbound traffic
  LogstashInstance:
    Type: AWS::EC2::Instance
    Metadata:
      AWS::CloudFormation::Init:
        configSets:
          InstallAndRun:
            - Prepare
            - Install
        Prepare:
          commands:
            01_import_logstash_yum:
              command: rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch
          sources:
            /tmp/repo: !Ref 'RepoLocation'
          files:
            /etc/yum.repos.d/logstash.repo:
              content: "[logstash-7.x]\nname=Elastic repository for 7.x packages\n\
                baseurl=https://artifacts.elastic.co/packages/7.x/yum\ngpgcheck=1\n\
                gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch\nenabled=1\n\
                autorefresh=1\ntype=rpm-md              \n"
              mode: '000600'
              owner: ec2-user
              group: ec2-user
        Install:
          packages:
            yum:
              jq: []
              git: []
              logstash: []
          files:
            /etc/cfn/cfn-hup.conf:
              content: !Sub |
                [main]
                stack=${AWS::StackId}
                region=${AWS::Region}
                interval=1
              mode: '000400'
              owner: root
              group: root
            /etc/cfn/hooks.d/cfn-auto-reloader.conf:
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.LogstashInstance.Metadata.AWS::CloudFormation::Init
                action=../../opt/aws/bin/cfn-init --stack ${AWS::StackName} --resource LogstashInstance --region ${AWS::Region}
                runas=root
          commands:
            01_copy_config:
              command: cp *.conf /etc/logstash/conf.d/
              cwd: /tmp/repo/conf/
            02_copy_settings:
              command: cp pipelines.yml jvm.options logstash.yml /etc/logstash/
              cwd: /tmp/repo/settings/
            03_create_logstash_keystore:
              command: echo y | bin/logstash-keystore --path.settings /etc/logstash
                create
              cwd: /usr/share/logstash/
            04_update_SNMP_targets:
              command: !Sub 'sed -i -e ''s/111.111.111.111/${SNMPInstance1.PrivateIp}/g''
                -e ''s/222.222.222.222/${SNMPInstance2.PrivateIp}/g'' snmp.conf'
              cwd: /etc/logstash/conf.d/
            05_update_aws_region:
              command: !Sub 'sed -i ''s/REGION/${AWS::Region}/g'' cloudwatch.conf'
              cwd: /etc/logstash/conf.d/
            06_add_user_keystore:
              command: !Sub 'aws secretsmanager get-secret-value  --region ${AWS::Region}
                --secret-id SNMPSecret      --query SecretString        --output text
                | jq .username | tr -d ''"''   |  bin/logstash-keystore --path.settings
                /etc/logstash add SNMP_USER'
              cwd: /usr/share/logstash/
            07_add_pwd_keystore:
              command: !Sub 'aws secretsmanager get-secret-value  --region ${AWS::Region}
                --secret-id SNMPSecret      --query SecretString        --output text
                | jq .password | tr -d ''"''   |  bin/logstash-keystore --path.settings
                /etc/logstash add SNMP_PWD'
              cwd: /usr/share/logstash/
          services:
            sysvinit:
              logstash:
                enabled: 'true'
                ensureRunning: 'true'
              cfn-hup:
                enabled: 'true'
                ensureRunning: 'true'
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    DependsOn: SNMPSecret
    Properties:
      ImageId: !Ref 'LatestAmiId'
      InstanceType: !Ref 'LogstashInstanceType'
      KeyName: !Ref 'MyKeyPair'
      IamInstanceProfile: !Ref 'LogstashInstanceProfile'
      SubnetId: !Select
        - 0
        - !Ref 'MySubnet'
      SecurityGroupIds:
        - !GetAtt 'LogstashSG.GroupId'
      Tags:
        - Key: Name
          Value: Logstash Server
      UserData: !Base64
        Fn::Sub: "#!/bin/bash -xe\nyum update -y aws-cfn-bootstrap\n/opt/aws/bin/cfn-init\
          \ -v --stack ${AWS::StackName} --resource LogstashInstance --configsets\
          \ InstallAndRun --region ${AWS::Region}\n/opt/aws/bin/cfn-signal -e $? --stack\
          \ ${AWS::StackName} --resource LogstashInstance --region ${AWS::Region}\
          \ \n"
    CreationPolicy:
      ResourceSignal:
        Timeout: PT10M
  SNMPInstance1:
    Type: AWS::EC2::Instance
    Metadata:
      AWS::CloudFormation::Init:
        configSets:
          InstallAndRun:
            - Install
        Install:
          packages:
            yum:
              net-snmp: []
              net-snmp-utils: []
              net-snmp-devel: []
              jq: []
          files:
            /etc/cfn/cfn-hup.conf:
              content: !Sub |
                [main]
                stack=${AWS::StackId}
                region=${AWS::Region}
                interval=1
              mode: 256
              owner: root
              group: root
            /etc/cfn/hooks.d/cfn-auto-reloader.conf:
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.SNMPInstance1.Metadata.AWS::CloudFormation::Init
                action=../../opt/aws/bin/cfn-init --stack ${AWS::StackName} --resource SNMPInstance1 --region ${AWS::Region}
                runas=root
          commands:
            01_create_SNMPv3_user:
              command: !Sub 'SECRET=$(aws secretsmanager get-secret-value  --region
                ${AWS::Region} --secret-id SNMPSecret      --query SecretString        --output
                text) ;  SNMPUSER=$(echo $SECRET | jq .username | tr -d ''"''   )
                ;SNMPPWD=$(echo $SECRET | jq .password | tr -d ''"''   ) ;net-snmp-config
                --create-snmpv3-user -ro -a MD5 -A $SNMPPWD $SNMPUSER >/dev/null'
          services:
            sysvinit:
              snmpd:
                enabled: 'true'
                ensureRunning: 'true'
              cfn-hup:
                enabled: 'true'
                ensureRunning: 'true'
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    DependsOn: SNMPSecret
    Properties:
      ImageId: !Ref 'LatestAmiId'
      InstanceType: !Ref 'SNMPInstanceType'
      KeyName: !Ref 'MyKeyPair'
      IamInstanceProfile: !Ref 'SNMPInstanceProfile'
      SubnetId: !Select
        - 0
        - !Ref 'MySubnet'
      SecurityGroupIds:
        - !GetAtt 'SNMPSG.GroupId'
      Tags:
        - Key: Name
          Value: SNMP Agent 1
      UserData: !Base64
        Fn::Sub: |
          #!/bin/bash -xe
          yum update -y aws-cfn-bootstrap
          /opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource SNMPInstance1 --configsets InstallAndRun --region ${AWS::Region}
          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource SNMPInstance1 --region ${AWS::Region}
    CreationPolicy:
      ResourceSignal:
        Timeout: PT10M
  SNMPInstance2:
    Type: AWS::EC2::Instance
    Metadata:
      AWS::CloudFormation::Init:
        configSets:
          InstallAndRun:
            - Install
        Install:
          packages:
            yum:
              net-snmp: []
              net-snmp-utils: []
              net-snmp-devel: []
              jq: []
          files:
            /etc/cfn/cfn-hup.conf:
              content: !Sub |
                [main]
                stack=${AWS::StackId}
                region=${AWS::Region}
                interval=1
              mode: 256
              owner: root
              group: root
            /etc/cfn/hooks.d/cfn-auto-reloader.conf:
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.SNMPInstance1.Metadata.AWS::CloudFormation::Init
                action=../../opt/aws/bin/cfn-init --stack ${AWS::StackName} --resource SNMPInstance1 --region ${AWS::Region}
                runas=root
          commands:
            01_create_SNMPv3_user:
              command: !Sub 'SECRET=$(aws secretsmanager get-secret-value  --region
                ${AWS::Region} --secret-id SNMPSecret      --query SecretString        --output
                text) ;  SNMPUSER=$(echo $SECRET | jq .username | tr -d ''"''   )
                ;SNMPPWD=$(echo $SECRET | jq .password | tr -d ''"''   ) ;net-snmp-config
                --create-snmpv3-user -ro -a MD5 -A $SNMPPWD $SNMPUSER >/dev/null'
          services:
            sysvinit:
              snmpd:
                enabled: 'true'
                ensureRunning: 'true'
              cfn-hup:
                enabled: 'true'
                ensureRunning: 'true'
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    DependsOn: SNMPSecret
    Properties:
      ImageId: !Ref 'LatestAmiId'
      InstanceType: !Ref 'SNMPInstanceType'
      KeyName: !Ref 'MyKeyPair'
      IamInstanceProfile: !Ref 'SNMPInstanceProfile'
      SubnetId: !Select
        - 0
        - !Ref 'MySubnet'
      SecurityGroupIds:
        - !GetAtt 'SNMPSG.GroupId'
      Tags:
        - Key: Name
          Value: SNMP Agent 2
      UserData: !Base64
        Fn::Sub: |
          #!/bin/bash -xe
          yum update -y aws-cfn-bootstrap
          /opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource SNMPInstance2 --configsets InstallAndRun --region ${AWS::Region}
          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource SNMPInstance2 --region ${AWS::Region}
    CreationPolicy:
      ResourceSignal:
        Timeout: PT10M
Outputs:
  SNMPAgent1:
    Description: Private IP address
    Value: !GetAtt 'SNMPInstance1.PrivateIp'
  SNMPAgent2:
    Description: Private IP address
    Value: !GetAtt 'SNMPInstance2.PrivateIp'