OCPBUGS-34975: aws: terraform: add spot instance support for masters

cmd/openshift-install/features.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+var (
+	outputJSON     = false
+	hiddenFeatures = []string{
+		"terraform-spot-masters",
+	}
+)
+
+func newListFeaturesCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:    "list-hidden-features",
+		Short:  "List supported hidden features",
+		Long:   "",
+		Hidden: true,
+		Args:   cobra.ExactArgs(0),
+		Run: func(_ *cobra.Command, _ []string) {
+			var out string
+			if outputJSON {
+				outb, err := json.Marshal(hiddenFeatures)
+				if err != nil {
+					logrus.Fatalf("failed to marshal output: %s", err.Error())
+				}
+				out = string(outb)
+			} else {
+				out = strings.Join(hiddenFeatures, "\n")
+			}
+			fmt.Println(out)
+		},
+	}
+	cmd.PersistentFlags().BoolVar(&outputJSON, "json", false, "print output in json format")
+	return cmd
+}

cmd/openshift-install/main.go

@@ -55,6 +55,7 @@ func installerMain() {
 		newCompletionCmd(),
 		newExplainCmd(),
 		newAgentCmd(ctx),
+		newListFeaturesCmd(),
 	} {
 		rootCmd.AddCommand(subCmd)
 	}

data/data/aws/bootstrap/main.tf

@@ -163,6 +163,16 @@ resource "aws_instance" "bootstrap" {
   vpc_security_group_ids      = [var.master_sg_id, aws_security_group.bootstrap.id]
   associate_public_ip_address = local.public_endpoints && var.aws_public_ipv4_pool == ""
 
+  dynamic "instance_market_options" {
+    for_each = var.aws_master_use_spot_instance ? [1] : []
+    content {
+      market_type = "spot"
+      spot_options {
+        spot_instance_type = "one-time"
+      }
+    }
+  }
+
   lifecycle {
     # Ignore changes in the AMI which force recreation of the resource. This
     # avoids accidental deletion of nodes whenever a new OS release comes out.

data/data/aws/cluster/main.tf

@@ -55,6 +55,7 @@ module "masters" {
   user_data_ign                    = var.ignition_master
   publish_strategy                 = var.aws_publish_strategy
   iam_role_name                    = var.aws_master_iam_role_name
+  use_spot_instance                = var.aws_master_use_spot_instance
 }
 
 module "iam" {

data/data/aws/cluster/master/main.tf

@@ -146,6 +146,16 @@ resource "aws_instance" "master" {
     device_index         = 0
   }
 
+  dynamic "instance_market_options" {
+    for_each = var.use_spot_instance ? [1] : []
+    content {
+      market_type = "spot"
+      spot_options {
+        spot_instance_type = "one-time"
+      }
+    }
+  }
+
   lifecycle {
     # Ignore changes in the AMI which force recreation of the resource. This
     # avoids accidental deletion of nodes whenever a new CoreOS Release comes

data/data/aws/cluster/master/variables.tf

@@ -101,3 +101,8 @@ variable "iam_role_name" {
   type = string
   description = "The name of the existing role to use for the instance profile"
 }
+
+variable "use_spot_instance" {
+  type = bool
+  description = "Whether to use Spot instances for masters"
+}

data/data/aws/variables-aws.tf

@@ -239,3 +239,9 @@ EOF
 
   default = ""
 }
+
+variable "aws_master_use_spot_instance" {
+  type = bool
+  description = "(optional) Whether to use instances from the Spot market for masters"
+  default = false
+}

pkg/tfvars/aws/aws.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 
 	machinev1beta1 "github.com/openshift/api/machine/v1beta1"
 	"github.com/openshift/installer/pkg/asset/ignition/bootstrap"
@@ -50,6 +51,7 @@ type Config struct {
 	PreserveBootstrapIgnition       bool              `json:"aws_preserve_bootstrap_ignition"`
 	MasterSecurityGroups            []string          `json:"aws_master_security_groups,omitempty"`
 	PublicIpv4Pool                  string            `json:"aws_public_ipv4_pool"`
+	MasterUseSpotInstance           bool              `json:"aws_master_use_spot_instance,omitempty"`
 }
 
 // TFVarsSources contains the parameters to be converted into Terraform variables
@@ -187,6 +189,11 @@ func TFVars(sources TFVarsSources) ([]byte, error) {
 		return nil, errors.New("EBS IOPS must be configured for the io1 root volume")
 	}
 
+	useSpotInstances := masterConfig.SpotMarketOptions != nil
+	if useSpotInstances {
+		logrus.Warn("Found Spot instance configuration. Please be warned, this is not advised.")
+	}
+
 	cfg := &Config{
 		CustomEndpoints:           endpoints,
 		Region:                    masterConfig.Placement.Region,
@@ -211,6 +218,7 @@ func TFVars(sources TFVarsSources) ([]byte, error) {
 		PreserveBootstrapIgnition: sources.PreserveBootstrapIgnition,
 		MasterSecurityGroups:      sources.MasterSecurityGroups,
 		PublicIpv4Pool:            sources.PublicIpv4Pool,
+		MasterUseSpotInstance:     useSpotInstances,
 	}
 
 	stubIgn, err := bootstrap.GenerateIgnitionShimWithCertBundleAndProxy(sources.IgnitionPresignedURL, sources.AdditionalTrustBundle, sources.Proxy)