gcp_gke_container_optimized_os.yaml

# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Enforce container optimized OS on GKE clusters
# https://cloud.google.com/container-optimized-os/docs/

apiVersion: templates.gatekeeper.sh/v1alpha1
kind: ConstraintTemplate
metadata:
  name: gcp-gke-container-optimized-os-v1
spec:
  crd:
    spec:
      names:
        kind: GCPGKEContainerOptimizedOSConstraintV1
      validation:
        openAPIV3Schema:
          properties:
            cos_containerd_allowed:
              type: boolean
              description: "If true, the constraint allows COS_CONTAINERD
                as an acceptable Container Optimized OS image."

  targets:
    validation.gcp.forsetisecurity.org:
      rego: | #INLINE("validator/gke_container_optimized_os.rego")
            #
            # Copyright 2019 Google LLC
            #
            # Licensed under the Apache License, Version 2.0 (the "License");
            # you may not use this file except in compliance with the License.
            # You may obtain a copy of the License at
            #
            #      http://www.apache.org/licenses/LICENSE-2.0
            #
            # Unless required by applicable law or agreed to in writing, software
            # distributed under the License is distributed on an "AS IS" BASIS,
            # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
            # See the License for the specific language governing permissions and
            # limitations under the License.
            #
            
            package templates.gcp.GCPGKEContainerOptimizedOSConstraintV1
            
            import data.validator.gcp.lib as lib
            
            deny[{
            	"msg": message,
            	"details": metadata,
            }] {
            	constraint := input.constraint
            	asset := input.asset
            	asset.asset_type == "container.googleapis.com/Cluster"
            	lib.get_constraint_params(constraint, params)
            	containerd_allowed = lib.get_default(params, "cos_containerd_allowed", false)
            
            	cluster := asset.resource.data
            	node_pools := lib.get_default(cluster, "nodePools", [])
            	node_pool := node_pools[_]
            	not cos_image(node_pool, containerd_allowed)
            
            	message := sprintf("Cluster %v has node pool %v without Container-Optimized OS.", [asset.name, node_pool.name])
            	metadata := {"resource": asset.name}
            }
            
            ###########################
            # Rule Utilities
            ###########################
            cos_image(node_pool, containerd_allowed) {
            	nodeConfig := lib.get_default(node_pool, "config", {})
            	imageType := lib.get_default(nodeConfig, "imageType", "")
            	imageType == "COS"
            }
            
            cos_image(node_pool, containerd_allowed) {
            	containerd_allowed
            	nodeConfig := lib.get_default(node_pool, "config", {})
            	imageType := lib.get_default(nodeConfig, "imageType", "")
            	imageType == "COS_CONTAINERD"
            }
            #ENDINLINE