diff --git a/dual-master/cf-cluster.yml b/dual-master/cf-cluster.yml
index 9f9ee7a..e6a2147 100644
--- a/dual-master/cf-cluster.yml
+++ b/dual-master/cf-cluster.yml
@@ -90,9 +90,51 @@
           LogGroupName: !Ref AWS::StackName
           RetentionInDays: 14
 
+  ReplicaECSAutoScalingGroup:
+    Type: AWS::AutoScaling::AutoScalingGroup
+    Properties:
+      VPCZoneIdentifier:
+        - !GetAtt ECSTaskNetworkStack.Outputs.PublicSubnetOneRef
+      LaunchConfigurationName: !Ref 'ReplicaLaunchConfiguration'
+      MinSize: '1'
+      MaxSize: '1'
+      DesiredCapacity: '1'
+    CreationPolicy:
+      ResourceSignal:
+        Timeout: PT15M
+    UpdatePolicy:
+      AutoScalingReplacingUpdate:
+        WillReplace: 'true'
+
+  ReplicaLaunchConfiguration:
+    Type: AWS::AutoScaling::LaunchConfiguration
+    Properties:
+      ImageId: !Ref 'ECSAMI'
+      SecurityGroups: [!Ref 'EcsHostSecurityGroup']
+      InstanceType: !Ref 'InstanceType'
+      IamInstanceProfile: !Ref 'EC2InstanceProfile'
+      KeyName: !Ref ECSKeyName
+      UserData:
+        Fn::Base64: !Sub |
+          #!/bin/bash -xe
+          echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
+          echo ECS_INSTANCE_ATTRIBUTES={\"target_group\":\"replica\"} >> /etc/ecs/ecs.config
+
+          # Make sure latest version of the helper scripts are installed as per recommendation:
+          # https://github.com/awsdocs/aws-cloudformation-user-guide/blob/master/doc_source/cfn-helper-scripts-reference.md#using-the-latest-version
+          yum install -y aws-cfn-bootstrap wget
+
+          # Install the CloudWatch Logs agent
+          wget https://s3.amazonaws.com/amazoncloudwatch-agent/centos/amd64/latest/amazon-cloudwatch-agent.rpm
+          rpm -U ./amazon-cloudwatch-agent.rpm
+          /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -s
+
+          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource ReplicaECSAutoScalingGroup --region ${AWS::Region}
+
+
   # Autoscaling group. This launches the actual EC2 instances that will register
   # themselves as members of the cluster, and run the docker containers.
-  ECSAutoScalingGroup:
+  MasterECSAutoScalingGroup:
     Type: AWS::AutoScaling::AutoScalingGroup
     Properties:
       VPCZoneIdentifier:
@@ -119,6 +161,7 @@
         Fn::Base64: !Sub |
           #!/bin/bash -xe
           echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
+          echo ECS_INSTANCE_ATTRIBUTES={\"target_group\":\"master\"} >> /etc/ecs/ecs.config
           # Make sure latest version of the helper scripts are installed as per recommendation:
           # https://github.com/awsdocs/aws-cloudformation-user-guide/blob/master/doc_source/cfn-helper-scripts-reference.md#using-the-latest-version
           yum install -y aws-cfn-bootstrap nfs-utils wget
@@ -245,7 +288,7 @@
           rpm -U ./amazon-cloudwatch-agent.rpm
           /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/home/ec2-user/gerritlogsaccess.json -s
           # Signal to CloudFormation aws-cfn-bootstrap has been correctly updated
-          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource ECSAutoScalingGroup --region ${AWS::Region}
+          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource MasterECSAutoScalingGroup --region ${AWS::Region}
 
   EC2InstanceProfile:
     Type: AWS::IAM::InstanceProfile
diff --git a/dual-master/cf-service-lb.yml b/dual-master/cf-service-lb.yml
index 257a5e9..42a09c4 100644
--- a/dual-master/cf-service-lb.yml
+++ b/dual-master/cf-service-lb.yml
@@ -108,6 +108,9 @@
             TaskRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             ExecutionRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             NetworkMode: bridge
+            PlacementConstraints:
+                - Expression: !Sub 'attribute:target_group == master'
+                  Type: "memberOf"
             ContainerDefinitions:
                 - Name: !Ref LBServiceName
                   Essential: true
diff --git a/dual-master/cf-service-master.yml b/dual-master/cf-service-master.yml
index b38df4a..8c18ffb 100644
--- a/dual-master/cf-service-master.yml
+++ b/dual-master/cf-service-master.yml
@@ -230,6 +230,9 @@
             TaskRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             ExecutionRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             NetworkMode: bridge
+            PlacementConstraints:
+                - Expression: !Sub 'attribute:target_group == master'
+                  Type: "memberOf"
             ContainerDefinitions:
                 - Name: !FindInMap ['Gerrit', 'Service', 'Name']
                   Essential: true
diff --git a/dual-master/cf-service-replication.yml b/dual-master/cf-service-replication.yml
index e85baf5..3fbc984 100644
--- a/dual-master/cf-service-replication.yml
+++ b/dual-master/cf-service-replication.yml
@@ -96,6 +96,9 @@
             TaskRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             ExecutionRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             NetworkMode: bridge
+            PlacementConstraints:
+              - Expression: !Sub 'attribute:target_group == master'
+                Type: "memberOf"
             ContainerDefinitions:
                 - Name: !Ref GitAdminSSHContainerName
                   Essential: true
diff --git a/dual-master/cf-service-slave.yml b/dual-master/cf-service-slave.yml
index 9d4aa7d..4f27e14 100644
--- a/dual-master/cf-service-slave.yml
+++ b/dual-master/cf-service-slave.yml
@@ -213,6 +213,9 @@
             TaskRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             ExecutionRoleArn: !GetAtt ECSTaskExecutionRoleStack.Outputs.TaskExecutionRoleRef
             NetworkMode: bridge
+            PlacementConstraints:
+                - Expression: !Sub 'attribute:target_group == replica'
+                  Type: "memberOf"
             ContainerDefinitions:
                 - Name: !Ref GerritServiceName
                   Essential: true