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Merge pull request #43260 from thockin/nodeport-allocation-rand-seed

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Automatic merge from submit-queue (batch tested with PRs 42379, 42668, 42876, 41473, 43260)

Don't use global rand for nodeport and IP allocs

Seed it at construction.
This commit is contained in:
Kubernetes Submit Queue 2017-03-30 23:36:30 -07:00 committed by GitHub
commit 223ac9f8b0
1 changed files with 25 additions and 10 deletions
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35
pkg/registry/core/service/allocator/bitmap.go
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@ -21,6 +21,7 @@ import (
"math/big"
"math/rand"
"sync"
"time"
)
// AllocationBitmap is a contiguous block of resources that can be allocated atomically.
@ -33,8 +34,8 @@ import (
//
// TODO: use RLE and compact the allocator to minimize space.
type AllocationBitmap struct {
// strategy is the strategy for choosing the next available item out of the range
strategy allocateStrategy
// strategy carries the details of how to choose the next available item out of the range
strategy bitAllocator
// max is the maximum size of the usable items in the range
max int
// rangeSpec is the range specifier, matching RangeAllocation.Range
@ -52,13 +53,17 @@ type AllocationBitmap struct {
var _ Interface = &AllocationBitmap{}
var _ Snapshottable = &AllocationBitmap{}
// allocateStrategy is a search strategy in the allocation map for a valid item.
type allocateStrategy func(allocated *big.Int, max, count int) (int, bool)
// bitAllocator represents a search strategy in the allocation map for a valid item.
type bitAllocator interface {
AllocateBit(allocated *big.Int, max, count int) (int, bool)
}
// NewAllocationMap creates an allocation bitmap using the random scan strategy.
func NewAllocationMap(max int, rangeSpec string) *AllocationBitmap {
a := AllocationBitmap{
strategy: randomScanStrategy,
strategy: randomScanStrategy{
rand: rand.New(rand.NewSource(time.Now().UnixNano())),
},
allocated: big.NewInt(0),
count: 0,
max: max,
@ -70,7 +75,7 @@ func NewAllocationMap(max int, rangeSpec string) *AllocationBitmap {
// NewContiguousAllocationMap creates an allocation bitmap using the contiguous scan strategy.
func NewContiguousAllocationMap(max int, rangeSpec string) *AllocationBitmap {
a := AllocationBitmap{
strategy: contiguousScanStrategy,
strategy: contiguousScanStrategy{},
allocated: big.NewInt(0),
count: 0,
max: max,
@ -99,7 +104,7 @@ func (r *AllocationBitmap) AllocateNext() (int, bool, error) {
r.lock.Lock()
defer r.lock.Unlock()
next, ok := r.strategy(r.allocated, r.max, r.count)
next, ok := r.strategy.AllocateBit(r.allocated, r.max, r.count)
if !ok {
return 0, false, nil
}
@ -193,11 +198,15 @@ func (r *AllocationBitmap) Restore(rangeSpec string, data []byte) error {
// randomScanStrategy chooses a random address from the provided big.Int, and then
// scans forward looking for the next available address (it will wrap the range if
// necessary).
func randomScanStrategy(allocated *big.Int, max, count int) (int, bool) {
type randomScanStrategy struct {
rand *rand.Rand
}
func (rss randomScanStrategy) AllocateBit(allocated *big.Int, max, count int) (int, bool) {
if count >= max {
return 0, false
}
offset := rand.Intn(max)
offset := rss.rand.Intn(max)
for i := 0; i < max; i++ {
at := (offset + i) % max
if allocated.Bit(at) == 0 {
@ -207,8 +216,12 @@ func randomScanStrategy(allocated *big.Int, max, count int) (int, bool) {
return 0, false
}
var _ bitAllocator = randomScanStrategy{}
// contiguousScanStrategy tries to allocate starting at 0 and filling in any gaps
func contiguousScanStrategy(allocated *big.Int, max, count int) (int, bool) {
type contiguousScanStrategy struct{}
func (contiguousScanStrategy) AllocateBit(allocated *big.Int, max, count int) (int, bool) {
if count >= max {
return 0, false
}
@ -219,3 +232,5 @@ func contiguousScanStrategy(allocated *big.Int, max, count int) (int, bool) {
}
return 0, false
}
var _ bitAllocator = contiguousScanStrategy{}