Move variable defaults to -var-file (#1079)

awslabs · Nov 21, 2022 · 5fcd34e · 5fcd34e
1 parent 21870b9
commit 5fcd34e
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Showing 4 changed files with 93 additions and 38 deletions.
diff --git a/Makefile b/Makefile
@@ -1,5 +1,5 @@
 PACKER_BINARY ?= packer
-PACKER_VARIABLES := $(shell $(PACKER_BINARY) inspect -machine-readable eks-worker-al2.json | grep 'template-variable' | awk -F ',' '{print $$4}')
+AVAILABLE_PACKER_VARIABLES := $(shell $(PACKER_BINARY) inspect -machine-readable eks-worker-al2.json | grep 'template-variable' | awk -F ',' '{print $$4}')
 
 K8S_VERSION_PARTS := $(subst ., ,$(kubernetes_version))
 K8S_VERSION_MINOR := $(word 1,${K8S_VERSION_PARTS}).$(word 2,${K8S_VERSION_PARTS})
@@ -65,14 +65,20 @@ lint: ## Check the source files for syntax and format issues
 test: ## run the test-harness
 	test/test-harness.sh
 
+# include only variables which have a defined value
+PACKER_VARIABLES := $(foreach packerVar,$(AVAILABLE_PACKER_VARIABLES),$(if $($(packerVar)),$(packerVar)))
+PACKER_VAR_FLAGS := -var-file eks-worker-al2-variables.json \
+$(if $(PACKER_VARIABLE_FILE),--var-file=$(PACKER_VARIABLE_FILE),) \
+$(foreach packerVar,$(PACKER_VARIABLES),-var $(packerVar)='$($(packerVar))')
+
 .PHONY: validate
 validate: ## Validate packer config
-	$(PACKER_BINARY) validate $(foreach packerVar,$(PACKER_VARIABLES), $(if $($(packerVar)),--var $(packerVar)='$($(packerVar))',)) eks-worker-al2.json
+	$(PACKER_BINARY) validate $(PACKER_VAR_FLAGS) eks-worker-al2.json
 
 .PHONY: k8s
 k8s: validate ## Build default K8s version of EKS Optimized AL2 AMI
 	@echo "$(T_GREEN)Building AMI for version $(T_YELLOW)$(kubernetes_version)$(T_GREEN) on $(T_YELLOW)$(arch)$(T_RESET)"
-	$(PACKER_BINARY) build -timestamp-ui -color=false $(foreach packerVar,$(PACKER_VARIABLES), $(if $($(packerVar)),--var $(packerVar)='$($(packerVar))',)) eks-worker-al2.json
+	$(PACKER_BINARY) build -timestamp-ui -color=false $(PACKER_VAR_FLAGS) eks-worker-al2.json
 
 # Build dates and versions taken from https://docs.aws.amazon.com/eks/latest/userguide/install-kubectl.html
 

diff --git a/README.md b/README.md
@@ -32,6 +32,18 @@ To build an Amazon EKS Worker AMI for a particular Kubernetes version run the fo
 ```bash
 make 1.23 ## Build a Amazon EKS Worker AMI for k8s 1.23
 ```
+
+### AMI template variables
+
+Default values for most variables are defined in [a default variable file](eks-worker-al2-variables.json).
+
+Users have the following options for specifying their own values:
+
+1. Provide a variable file with the `PACKER_VARIABLE_FILE` argument to `make`. Values in this file will override values in the default variable file. Your variable file does not need to include all possible variables, as it will be merged with the default variable file.
+2. Pass a key-value pair for any template variable to `make`. These values will override any values specified using the first method.
+
+**Note** that some variables (such as `arch` and `kubernetes_version`) do not have a sensible, static default, and are satisfied by the Makefile. Such variables do not appear in the default variable file, and must be overridden (if necessary) by the second method described above.
+
 ### Building against other versions of Kubernetes binaries
 To build an Amazon EKS Worker AMI with other versions of Kubernetes that are not listed above run the following AWS Command
 Line Interface (AWS CLI) commands to obtain values for KUBERNETES_VERSION, KUBERNETES_BUILD_DATE, PLATFORM, ARCH from S3

diff --git a/eks-worker-al2-variables.json b/eks-worker-al2-variables.json
@@ -0,0 +1,36 @@
+{
+    "additional_yum_repos": "",
+    "ami_description": "EKS Kubernetes Worker AMI with AmazonLinux2 image",
+    "ami_regions": "",
+    "ami_users": "",
+    "associate_public_ip_address": "",
+    "aws_access_key_id": "{{env `AWS_ACCESS_KEY_ID`}}",
+    "aws_region": "us-west-2",
+    "aws_secret_access_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
+    "aws_session_token": "{{env `AWS_SESSION_TOKEN`}}",
+    "binary_bucket_name": "amazon-eks",
+    "binary_bucket_region": "us-west-2",
+    "cache_container_images": "false",    
+    "cni_plugin_version": "v0.8.6",
+    "containerd_version": "1.6.6-1.amzn2.0.2",
+    "creator": "{{env `USER`}}",
+    "docker_version": "20.10.17-1.amzn2.0.1",
+    "encrypted": "false",
+    "kernel_version": "",
+    "kms_key_id": "",
+    "launch_block_device_mappings_volume_size": "8",
+    "pause_container_version": "3.5",    
+    "pull_cni_from_github": "true",
+    "remote_folder": "",
+    "runc_version": "1.1.3-1.amzn2.0.2",
+    "security_group_id": "",
+    "sonobuoy_e2e_registry": "",
+    "source_ami_filter_name": "amzn2-ami-minimal-hvm-*",
+    "source_ami_id": "",
+    "source_ami_owners": "137112412989",
+    "ssh_interface": "",
+    "ssh_username": "ec2-user",
+    "subnet_id": "",
+    "temporary_security_group_source_cidrs": "",
+    "volume_type": "gp2"
+}
diff --git a/eks-worker-al2.json b/eks-worker-al2.json
@@ -1,44 +1,45 @@
 {
+  "_comment": "All template variables are enumerated here; and most variables have a default value defined in eks-worker-al2-variables.json",
   "variables": {
-    "additional_yum_repos": "",
-    "ami_description": "EKS Kubernetes Worker AMI with AmazonLinux2 image",
+    "additional_yum_repos": null,
+    "ami_description": null,
     "ami_name": null,
-    "ami_regions": "",
-    "ami_users": "",
+    "ami_regions": null,
+    "ami_users": null,
     "arch": null,
-    "associate_public_ip_address": "",
-    "aws_access_key_id": "{{env `AWS_ACCESS_KEY_ID`}}",
-    "aws_region": "us-west-2",
-    "aws_secret_access_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
-    "aws_session_token": "{{env `AWS_SESSION_TOKEN`}}",
-    "binary_bucket_name": "amazon-eks",
-    "binary_bucket_region": "us-west-2",
-    "cache_container_images": "false",
-    "cni_plugin_version": "v0.8.6",
-    "containerd_version": "1.6.6-1.amzn2.0.2",
-    "creator": "{{env `USER`}}",
-    "docker_version": "20.10.17-1.amzn2.0.1",
-    "encrypted": "false",
+    "associate_public_ip_address": null,
+    "aws_access_key_id": null,
+    "aws_region": null,
+    "aws_secret_access_key": null,
+    "aws_session_token": null,
+    "binary_bucket_name": null,
+    "binary_bucket_region": null,
+    "cache_container_images": null,    
+    "cni_plugin_version": null,
+    "containerd_version": null,
+    "creator": null,
+    "docker_version": null,
+    "encrypted": null,
     "instance_type": null,
-    "kernel_version": "",
-    "kms_key_id": "",
+    "kernel_version": null,
+    "kms_key_id": null,
     "kubernetes_build_date": null,
     "kubernetes_version": null,
-    "launch_block_device_mappings_volume_size": "8",
-    "pause_container_version": "3.5",
-    "pull_cni_from_github": "true",
-    "remote_folder": "",
-    "runc_version": "1.1.3-1.amzn2.0.2",
-    "security_group_id": "",
-    "sonobuoy_e2e_registry": "",
-    "source_ami_filter_name": "amzn2-ami-minimal-hvm-*",
-    "source_ami_id": "",
-    "source_ami_owners": "137112412989",
-    "ssh_interface": "",
-    "ssh_username": "ec2-user",
-    "subnet_id": "",
-    "temporary_security_group_source_cidrs": "",
-    "volume_type": "gp2"
+    "launch_block_device_mappings_volume_size": null,
+    "pause_container_version": null,    
+    "pull_cni_from_github": null,
+    "remote_folder": null,
+    "runc_version": null,
+    "security_group_id": null,
+    "sonobuoy_e2e_registry": null,
+    "source_ami_filter_name": null,
+    "source_ami_id": null,
+    "source_ami_owners": null,
+    "ssh_interface": null,
+    "ssh_username": null,
+    "subnet_id": null,
+    "temporary_security_group_source_cidrs": null,
+    "volume_type": null
   },
   "builders": [
     {
@@ -223,4 +224,4 @@
       }
     }
   ]
-}
+}