97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: MPL-2.0
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package drainer
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import (
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"github.com/hashicorp/nomad/nomad/structs"
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)
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const (
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// defaultMaxIdsPerTxn is the maximum number of IDs that can be included in a
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// single Raft transaction. This is to ensure that the Raft message
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// does not become too large.
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defaultMaxIdsPerTxn = (1024 * 256) / 36 // 0.25 MB of ids.
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)
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// partitionIds takes a set of IDs and returns a partitioned view of them such
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// that no batch would result in an overly large raft transaction.
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func partitionIds(maxIds int, ids []string) [][]string {
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index := 0
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total := len(ids)
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var partitions [][]string
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for remaining := total - index; remaining > 0; remaining = total - index {
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if remaining < maxIds {
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partitions = append(partitions, ids[index:])
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break
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} else {
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partitions = append(partitions, ids[index:index+maxIds])
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index += maxIds
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}
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}
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return partitions
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}
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// transitionTuple is used to group desired transitions and evals
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type transitionTuple struct {
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Transitions map[string]*structs.DesiredTransition
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Evals []*structs.Evaluation
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}
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// partitionAllocDrain returns a list of alloc transitions and evals to apply
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// in a single raft transaction.This is necessary to ensure that the Raft
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// transaction does not become too large.
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func partitionAllocDrain(maxIds int, transitions map[string]*structs.DesiredTransition,
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evals []*structs.Evaluation) []*transitionTuple {
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// Determine a stable ordering of the transitioning allocs
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allocs := make([]string, 0, len(transitions))
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for id := range transitions {
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allocs = append(allocs, id)
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}
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var requests []*transitionTuple
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submittedEvals, submittedTrans := 0, 0
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for submittedEvals != len(evals) || submittedTrans != len(transitions) {
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req := &transitionTuple{
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Transitions: make(map[string]*structs.DesiredTransition),
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}
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requests = append(requests, req)
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available := maxIds
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// Add the allocs first
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if remaining := len(allocs) - submittedTrans; remaining > 0 {
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if remaining <= available {
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for _, id := range allocs[submittedTrans:] {
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req.Transitions[id] = transitions[id]
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}
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available -= remaining
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submittedTrans += remaining
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} else {
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for _, id := range allocs[submittedTrans : submittedTrans+available] {
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req.Transitions[id] = transitions[id]
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}
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submittedTrans += available
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// Exhausted space so skip adding evals
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continue
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}
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}
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// Add the evals
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if remaining := len(evals) - submittedEvals; remaining > 0 {
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if remaining <= available {
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req.Evals = evals[submittedEvals:]
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submittedEvals += remaining
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} else {
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req.Evals = evals[submittedEvals : submittedEvals+available]
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submittedEvals += available
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}
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}
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}
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return requests
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}
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