buildenv: remove EC2 zone configuration options

There is no need to set availability zones for EC2 resources at this
time. The resources currently in use are available to all zones within
a single region.

For golang/go#36841

Change-Id: Ifcb2c3404fba2489741c31fe63ad4e7747639ad9
Reviewed-on: https://go-review.googlesource.com/c/build/+/255359
Trust: Carlos Amedee <carlos@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>

buildenv/envs.go

@@ -74,18 +74,11 @@ type Environment struct {
 	// other fields.
 	ControlZone string
 
-	// PreferredEC2Zone is the preffered AWS availability zone.
-	PreferredEC2Zone string
-
 	// VMZones are the GCE zones that the VMs will be deployed to. These
 	// GCE zones will be periodically cleaned by deleting old VMs. The zones
 	// should all exist within a single region.
 	VMZones []string
 
-	// VMEC2Zones are the AWS availability zones that the VMs will be deployed to.
-	// The availability zones should all exist within a single region.
-	VMEC2Zones []string
-
 	// StaticIP is the public, static IP address that will be attached to the
 	// coordinator instance. The zero value means the address will be looked
 	// up by name. This field is optional.
@@ -149,8 +142,6 @@ type Environment struct {
 	AWSSecurityGroup string
 
 	// AWSRegion is the region where AWS resources are deployed.
-	// The availability zones set in VMEC2Zones should all reside
-	// within this region.
 	AWSRegion string
 }
 
@@ -168,16 +159,6 @@ func (e Environment) RandomVMZone() string {
 	return e.VMZones[rand.Intn(len(e.VMZones))]
 }
 
-// RandomEC2VMZone returns a randomly selected zone from the zones in
-// VMAvailabilityZones. The PreferredAvailabilityZone value will be
-// returned if VMAvailabilityZones is not set.
-func (e Environment) RandomEC2VMZone() string {
-	if len(e.VMEC2Zones) == 0 {
-		return e.PreferredEC2Zone
-	}
-	return e.VMEC2Zones[rand.Intn(len(e.VMEC2Zones))]
-}
-
 // Region returns the GCE region, derived from its zone.
 func (e Environment) Region() string {
 	return e.ControlZone[:strings.LastIndex(e.ControlZone, "-")]
@@ -266,7 +247,6 @@ var Staging = &Environment{
 	IsProd:                true,
 	ControlZone:           "us-central1-f",
 	VMZones:               []string{"us-central1-a", "us-central1-b", "us-central1-c", "us-central1-f"},
-	VMEC2Zones:            []string{"us-east-1a", "us-east-1b"},
 	StaticIP:              "104.154.113.235",
 	MachineType:           "n1-standard-1",
 	PreferContainersOnCOS: true,
@@ -302,7 +282,6 @@ var Production = &Environment{
 	IsProd:                true,
 	ControlZone:           "us-central1-f",
 	VMZones:               []string{"us-central1-a", "us-central1-b", "us-central1-c", "us-central1-f"},
-	VMEC2Zones:            []string{"us-east-2a", "us-east-2b"},
 	StaticIP:              "107.178.219.46",
 	MachineType:           "n1-standard-4",
 	PreferContainersOnCOS: true,

buildenv/envs_test.go

@@ -50,48 +50,6 @@ func TestEnvironmentNextZone(t *testing.T) {
 	}
 }
 
-func TestEnvironmentRandomEC2VMZone(t *testing.T) {
-	testCases := []struct {
-		name      string
-		env       Environment
-		wantOneOf []string
-	}{
-		{
-			name: "zones-not-set",
-			env: Environment{
-				PreferredEC2Zone: "zone-a",
-				VMEC2Zones:       []string{},
-			},
-			wantOneOf: []string{"zone-a"},
-		},
-		{
-			name: "zone-and-zones-set",
-			env: Environment{
-				PreferredEC2Zone: "zone-a",
-				VMEC2Zones:       []string{"zone-b", "zone-c"},
-			},
-
-			wantOneOf: []string{"zone-b", "zone-c"},
-		},
-		{
-			name: "zones-only-contains-one-entry",
-			env: Environment{
-				PreferredEC2Zone: "zone-a",
-				VMEC2Zones:       []string{"zone-b"},
-			},
-			wantOneOf: []string{"zone-b"},
-		},
-	}
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			got := tc.env.RandomEC2VMZone()
-			if !containsString(got, tc.wantOneOf) {
-				t.Errorf("got=%q; want %v", got, tc.wantOneOf)
-			}
-		})
-	}
-}
-
 func containsString(item string, items []string) bool {
 	for _, s := range items {
 		if item == s {