diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 22cf7e3..d60e97c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -39,7 +39,9 @@ jobs:
           node-version: 20
 
       - name: Install LocalStack
-        run: pip install localstack awscli-local[ver1] virtualenv
+        run: |
+          pip install localstack awscli-local[ver1] virtualenv
+          pip install --upgrade boto3 botocore
 
       - name: Setup config
         run: |
diff --git a/elb-load-balancing/serverless.yml b/elb-load-balancing/serverless.yml
index 935f1d2..c2d69bd 100644
--- a/elb-load-balancing/serverless.yml
+++ b/elb-load-balancing/serverless.yml
@@ -33,6 +33,7 @@ resources:
         Name: lb-test-1
         Subnets:
           - !Ref Subnet
+          - !Ref Subnet2
     HTTPListener:
       Type: AWS::ElasticLoadBalancingV2::Listener
       Properties:
@@ -53,12 +54,21 @@ resources:
         AvailabilityZone: !Select
           - 0
           - Fn::GetAZs: !Ref "AWS::Region"
+    # An ALB requires at least two subnets in two different Availability Zones.
+    Subnet2:
+      Type: AWS::EC2::Subnet
+      Properties:
+        VpcId: !Ref VPC
+        CidrBlock: 12.2.2.0/24
+        AvailabilityZone: !Select
+          - 1
+          - Fn::GetAZs: !Ref "AWS::Region"
     VPC:
       Type: AWS::EC2::VPC
       Properties:
         EnableDnsSupport: "true"
         EnableDnsHostnames: "true"
-        CidrBlock: 12.2.1.0/24
+        CidrBlock: 12.2.0.0/16
 
 plugins:
   - serverless-deployment-bucket