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Add dry-run support to the IP allocator subsystem

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This commit is contained in:
Tim Hockin 2020-11-25 13:07:36 -08:00
parent 237434bd42
commit 52856f3fbe
2 changed files with 161 additions and 19 deletions
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88
pkg/registry/core/service/ipallocator/allocator.go
View File

@ -37,6 +37,9 @@ type Interface interface {
CIDR() net.IPNet
IPFamily() api.IPFamily
Has(ip net.IP) bool
// DryRun offers a way to try operations without persisting them.
DryRun() Interface
}
var (
@ -46,11 +49,12 @@ var (
)
type ErrNotInRange struct {
IP net.IP
ValidRange string
}
func (e *ErrNotInRange) Error() string {
return fmt.Sprintf("provided IP is not in the valid range. The range of valid IPs is %s", e.ValidRange)
return fmt.Sprintf("the provided IP (%v) is not in the valid range. The range of valid IPs is %s", e.IP, e.ValidRange)
}
// Range is a contiguous block of IPs that can be allocated atomically.
@ -98,11 +102,13 @@ func New(cidr *net.IPNet, allocatorFactory allocator.AllocatorFactory) (*Range,
}
} else {
family = api.IPv4Protocol
// Don't use the IPv4 network's broadcast address.
// Don't use the IPv4 network's broadcast address, but don't just
// Allocate() it - we don't ever want to be able to release it.
max--
}
// Don't use the network's ".0" address.
// Don't use the network's ".0" address, but don't just Allocate() it - we
// don't ever want to be able to release it.
base.Add(base, big.NewInt(1))
max--
@ -114,6 +120,7 @@ func New(cidr *net.IPNet, allocatorFactory allocator.AllocatorFactory) (*Range,
}
var err error
r.alloc, err = allocatorFactory(r.max, rangeSpec)
return &r, err
}
@ -162,18 +169,35 @@ func (r *Range) CIDR() net.IPNet {
return *r.net
}
// DryRun returns a non-persisting form of this Range.
func (r *Range) DryRun() Interface {
return dryRunRange{r}
}
// For clearer code.
const dryRunTrue = true
const dryRunFalse = false
// Allocate attempts to reserve the provided IP. ErrNotInRange or
// ErrAllocated will be returned if the IP is not valid for this range
// or has already been reserved. ErrFull will be returned if there
// are no addresses left.
func (r *Range) Allocate(ip net.IP) error {
return r.allocate(ip, dryRunFalse)
}
func (r *Range) allocate(ip net.IP, dryRun bool) error {
label := r.CIDR()
ok, offset := r.contains(ip)
if !ok {
// update metrics
clusterIPAllocationErrors.WithLabelValues(label.String()).Inc()
return &ErrNotInRange{r.net.String()}
return &ErrNotInRange{ip, r.net.String()}
}
if dryRun {
// Don't bother to check whether the IP is actually free. It's racy and
// not worth the effort to plumb any further.
return nil
}
allocated, err := r.alloc.Allocate(offset)
@ -200,7 +224,17 @@ func (r *Range) Allocate(ip net.IP) error {
// AllocateNext reserves one of the IPs from the pool. ErrFull may
// be returned if there are no addresses left.
func (r *Range) AllocateNext() (net.IP, error) {
return r.allocateNext(dryRunFalse)
}
func (r *Range) allocateNext(dryRun bool) (net.IP, error) {
label := r.CIDR()
if dryRun {
// Don't bother finding a free value. It's racy and not worth the
// effort to plumb any further.
return r.CIDR().IP, nil
}
offset, ok, err := r.alloc.AllocateNext()
if err != nil {
// update metrics
@ -226,10 +260,17 @@ func (r *Range) AllocateNext() (net.IP, error) {
// unallocated IP or an IP out of the range is a no-op and
// returns no error.
func (r *Range) Release(ip net.IP) error {
return r.release(ip, dryRunFalse)
}
func (r *Range) release(ip net.IP, dryRun bool) error {
ok, offset := r.contains(ip)
if !ok {
return nil
}
if dryRun {
return nil
}
err := r.alloc.Release(offset)
if err == nil {
@ -312,3 +353,40 @@ func (r *Range) contains(ip net.IP) (bool, int) {
func calculateIPOffset(base *big.Int, ip net.IP) int {
return int(big.NewInt(0).Sub(netutils.BigForIP(ip), base).Int64())
}
// dryRunRange is a shim to satisfy Interface without persisting state.
type dryRunRange struct {
real *Range
}
func (dry dryRunRange) Allocate(ip net.IP) error {
return dry.real.allocate(ip, dryRunTrue)
}
func (dry dryRunRange) AllocateNext() (net.IP, error) {
return dry.real.allocateNext(dryRunTrue)
}
func (dry dryRunRange) Release(ip net.IP) error {
return dry.real.release(ip, dryRunTrue)
}
func (dry dryRunRange) ForEach(cb func(net.IP)) {
dry.real.ForEach(cb)
}
func (dry dryRunRange) CIDR() net.IPNet {
return dry.real.CIDR()
}
func (dry dryRunRange) IPFamily() api.IPFamily {
return dry.real.IPFamily()
}
func (dry dryRunRange) DryRun() Interface {
return dry
}
func (dry dryRunRange) Has(ip net.IP) bool {
return dry.real.Has(ip)
}

92
pkg/registry/core/service/ipallocator/allocator_test.go
View File

@ -76,34 +76,34 @@ func TestAllocate(t *testing.T) {
}
t.Logf("base: %v", r.base.Bytes())
if f := r.Free(); f != tc.free {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, tc.free, f)
}
rCIDR := r.CIDR()
if rCIDR.String() != tc.cidr {
t.Errorf("allocator returned a different cidr")
t.Errorf("[%s] wrong CIDR: expected %v, got %v", tc.name, tc.cidr, rCIDR.String())
}
if r.IPFamily() != tc.family {
t.Errorf("allocator returned wrong IP family")
t.Errorf("[%s] wrong IP family: expected %v, got %v", tc.name, tc.family, r.IPFamily())
}
if f := r.Used(); f != 0 {
t.Errorf("Test %s unexpected used %d", tc.name, f)
t.Errorf("[%s]: wrong used: expected %d, got %d", tc.name, 0, f)
}
found := sets.NewString()
count := 0
for r.Free() > 0 {
ip, err := r.AllocateNext()
if err != nil {
t.Fatalf("Test %s error @ %d: %v", tc.name, count, err)
t.Fatalf("[%s] error @ %d: %v", tc.name, count, err)
}
count++
if !cidr.Contains(ip) {
t.Fatalf("Test %s allocated %s which is outside of %s", tc.name, ip, cidr)
t.Fatalf("[%s] allocated %s which is outside of %s", tc.name, ip, cidr)
}
if found.Has(ip.String()) {
t.Fatalf("Test %s allocated %s twice @ %d", tc.name, ip, count)
t.Fatalf("[%s] allocated %s twice @ %d", tc.name, ip, count)
}
found.Insert(ip.String())
}
@ -116,17 +116,17 @@ func TestAllocate(t *testing.T) {
t.Fatal(err)
}
if f := r.Free(); f != 1 {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, 1, f)
}
if f := r.Used(); f != (tc.free - 1) {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, tc.free-1, f)
}
ip, err := r.AllocateNext()
if err != nil {
t.Fatal(err)
}
if !released.Equal(ip) {
t.Errorf("Test %s unexpected %s : %s", tc.name, ip, released)
t.Errorf("[%s] unexpected %s : %s", tc.name, ip, released)
}
if err := r.Release(released); err != nil {
@ -142,19 +142,19 @@ func TestAllocate(t *testing.T) {
t.Fatal(err)
}
if f := r.Free(); f != 1 {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, 1, f)
}
if f := r.Used(); f != (tc.free - 1) {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, tc.free-1, f)
}
if err := r.Allocate(released); err != nil {
t.Fatal(err)
}
if f := r.Free(); f != 0 {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, 0, f)
}
if f := r.Used(); f != tc.free {
t.Errorf("Test %s unexpected free %d", tc.name, f)
t.Errorf("[%s] wrong free: expected %d, got %d", tc.name, tc.free, f)
}
}
}
@ -514,3 +514,67 @@ func expectMetrics(t *testing.T, label string, em testMetrics) {
t.Fatalf("metrics error: expected %v, received %v", em, m)
}
}
func TestDryRun(t *testing.T) {
testCases := []struct {
name string
cidr string
family api.IPFamily
}{{
name: "IPv4",
cidr: "192.168.1.0/24",
family: api.IPv4Protocol,
}, {
name: "IPv6",
cidr: "2001:db8:1::/48",
family: api.IPv6Protocol,
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
_, cidr, err := netutils.ParseCIDRSloppy(tc.cidr)
if err != nil {
t.Fatalf("unexpected failure: %v", err)
}
r, err := NewInMemory(cidr)
if err != nil {
t.Fatalf("unexpected failure: %v", err)
}
baseUsed := r.Used()
rCIDR := r.DryRun().CIDR()
if rCIDR.String() != tc.cidr {
t.Errorf("allocator returned a different cidr")
}
if r.DryRun().IPFamily() != tc.family {
t.Errorf("allocator returned wrong IP family")
}
expectUsed := func(t *testing.T, r *Range, expect int) {
t.Helper()
if u := r.Used(); u != expect {
t.Errorf("unexpected used count: got %d, wanted %d", u, expect)
}
}
expectUsed(t, r, baseUsed)
err = r.DryRun().Allocate(netutils.AddIPOffset(netutils.BigForIP(cidr.IP), 1))
if err != nil {
t.Fatalf("unexpected failure: %v", err)
}
expectUsed(t, r, baseUsed)
_, err = r.DryRun().AllocateNext()
if err != nil {
t.Fatalf("unexpected failure: %v", err)
}
expectUsed(t, r, baseUsed)
if err := r.DryRun().Release(cidr.IP); err != nil {
t.Fatalf("unexpected failure: %v", err)
}
expectUsed(t, r, baseUsed)
})
}
}