diff --git a/.bazelversion b/.bazelversion
new file mode 100644
index 0000000..ee74734
--- /dev/null
+++ b/.bazelversion
@@ -0,0 +1 @@
+4.1.0
diff --git a/infrastructure/aws/ami/continuous_integration/packer-conf.json b/infrastructure/aws/ami/continuous_integration/packer-conf.json
deleted file mode 100644
index 45514f9..0000000
--- a/infrastructure/aws/ami/continuous_integration/packer-conf.json
+++ /dev/null
@@ -1,23 +0,0 @@
-{
-  "variables": {
-    "aws_access_key": "",
-    "aws_secret_key": "",
-    "region": "us-east-2"
-  },
-  "builders": [{
-    "type": "amazon-ebs",
-    "access_key": "{{user `aws_access_key`}}",
-    "secret_key": "{{user `aws_secret_key`}}",
-    "region": "us-east-2",
-    "source_ami": "ami-05512b79a46f1fabb",
-    "instance_type": "t2.small",
-    "ssh_username": "ec2-user",
-    "ami_name": "continuous-integration {{timestamp}}"
-  }],
-  "provisioners": [
-    {
-      "type": "shell",
-      "script": "./prepare.sh"
-    }
-  ]
-}
diff --git a/infrastructure/aws/ami/continuous_integration/packer-conf.pkr.hcl b/infrastructure/aws/ami/continuous_integration/packer-conf.pkr.hcl
new file mode 100644
index 0000000..a4a5faa
--- /dev/null
+++ b/infrastructure/aws/ami/continuous_integration/packer-conf.pkr.hcl
@@ -0,0 +1,63 @@
+# This file was autogenerated by the 'packer hcl2_upgrade' command. We
+# recommend double checking that everything is correct before going forward. We
+# also recommend treating this file as disposable. The HCL2 blocks in this
+# file can be moved to other files. For example, the variable blocks could be
+# moved to their own 'variables.pkr.hcl' file, etc. Those files need to be
+# suffixed with '.pkr.hcl' to be visible to Packer. To use multiple files at
+# once they also need to be in the same folder. 'packer inspect folder/'
+# will describe to you what is in that folder.
+
+# Avoid mixing go templating calls ( for example ```{{ upper(`string`) }}``` )
+# and HCL2 calls (for example '${ var.string_value_example }' ). They won't be
+# executed together and the outcome will be unknown.
+
+# All generated input variables will be of 'string' type as this is how Packer JSON
+# views them; you can change their type later on. Read the variables type
+# constraints documentation
+# https://www.packer.io/docs/templates/hcl_templates/variables#type-constraints for more info.
+variable "aws_access_key" {
+  type    = string
+}
+
+variable "aws_secret_key" {
+  type    = string
+}
+
+variable "bazel_version" {
+  type    = string
+}
+
+variable "region" {
+  type    = string
+  default = "us-east-2"
+}
+
+# "timestamp" template function replacement
+locals { timestamp = regex_replace(timestamp(), "[- TZ:]", "") }
+
+# source blocks are generated from your builders; a source can be referenced in
+# build blocks. A build block runs provisioner and post-processors on a
+# source. Read the documentation for source blocks here:
+# https://www.packer.io/docs/templates/hcl_templates/blocks/source
+source "amazon-ebs" "autogenerated_1" {
+  access_key    = "${var.aws_access_key}"
+  ami_name      = "continuous-integration ${local.timestamp}"
+  instance_type = "t2.small"
+  region        = "us-east-2"
+  secret_key    = "${var.aws_secret_key}"
+  source_ami    = "ami-05512b79a46f1fabb"
+  ssh_username  = "ec2-user"
+}
+
+# a build block invokes sources and runs provisioning steps on them. The
+# documentation for build blocks can be found here:
+# https://www.packer.io/docs/templates/hcl_templates/blocks/build
+build {
+  sources = ["source.amazon-ebs.autogenerated_1"]
+
+  provisioner "shell" {
+    environment_vars = [format("BAZEL_VERSION=%s", var.bazel_version)]
+    script           = "./prepare.sh"
+  }
+
+}
diff --git a/infrastructure/aws/ami/continuous_integration/prepare.sh b/infrastructure/aws/ami/continuous_integration/prepare.sh
index 127096a..9bf61b2 100644
--- a/infrastructure/aws/ami/continuous_integration/prepare.sh
+++ b/infrastructure/aws/ami/continuous_integration/prepare.sh
@@ -2,27 +2,31 @@
 
 set -o errexit
 set -o pipefail
+set -o nounset
 
-BAZEL_VERSION="3.3.0"
+## Install Bazel and the other project's dependencies
+main() {
+  local bazel_version
+  bazel_version="${BAZEL_VERSION}"
 
-## Install Bazel's and Project's dependencies
+  # NOTE: Amazon Linux 2 uses 'yum' not 'apt-get'
+  sudo yum groupinstall -y "Development Tools"
+  sudo yum install -y zip unzip
+  # Copied from https://github.com/buildkite/elastic-ci-stack-for-aws/pull/583/files
+  sudo yum install -y python3-pip python3 python3-setuptools
+  sudo yum install -y java-1.8.0-openjdk-devel
 
-# NOTE: Amazon Linux 2 uses 'yum' not 'apt-get'
-sudo yum groupinstall -y "Development Tools"
-sudo yum install -y zip unzip
-# Copied from https://github.com/buildkite/elastic-ci-stack-for-aws/pull/583/files
-sudo yum install -y python3-pip python3 python3-setuptools
-sudo yum install -y java-1.8.0-openjdk-devel
+  # Install Node
+  curl -o- "https://raw.githubusercontent.com/nvm-sh/nvm/v0.34.0/install.sh" | bash
+  # shellcheck disable=SC1090
+  . ~/.nvm/nvm.sh
+  nvm install node
 
-# Node
-curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.34.0/install.sh | bash
-# shellcheck disable=SC1090
-. ~/.nvm/nvm.sh
-nvm install node
+  ## Install Bazel from source
+  curl -sSL -O \
+    "https://github.com/bazelbuild/bazel/releases/download/${bazel_version}/bazel-${bazel_version}-installer-linux-x86_64.sh"
+  chmod +x "bazel-${bazel_version}-installer-linux-x86_64.sh"
+  sudo "./bazel-${bazel_version}-installer-linux-x86_64.sh"
+}
 
-## Install Bazel from source
-
-curl -sSL -O \
-  "https://github.com/bazelbuild/bazel/releases/download/${BAZEL_VERSION}/bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh"
-chmod +x "bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh"
-sudo "./bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh"
+main "$@"
diff --git a/infrastructure/aws/ami/continuous_integration/rebuild.sh b/infrastructure/aws/ami/continuous_integration/rebuild.sh
index 36084f1..f55dcbd 100755
--- a/infrastructure/aws/ami/continuous_integration/rebuild.sh
+++ b/infrastructure/aws/ami/continuous_integration/rebuild.sh
@@ -4,7 +4,23 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-packer build \
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+
+main() {
+  local bazel_version
+  local bazelversion_dotfile_path
+
+  bazelversion_dotfile_path="${REPO_ROOT}/.bazelversion"
+  bazel_version="$(tr -d '\n' < "${bazelversion_dotfile_path}")"
+
+  cd "${REPO_ROOT}/infrastructure/aws/ami/continuous_integration/"
+
+  packer build \
     -var "aws_access_key=${AWS_ACCESS_KEY_ID}" \
     -var "aws_secret_key=${AWS_SECRET_ACCESS_KEY}" \
-    "packer-conf.json"
+    -var "bazel_version=${bazel_version}" \
+    "./packer-conf.pkr.hcl"
+}
+
+
+main "$@"