X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/bdb92619b5f6d920119b8c32c3027cf4b751ed16..8e96f8cacd728b1a1b4316ecb2fb7cd233a97144:/services/keep-balance/balance.go

diff --git a/services/keep-balance/balance.go b/services/keep-balance/balance.go
index 9389f19ed8..9338075d01 100644
--- a/services/keep-balance/balance.go
+++ b/services/keep-balance/balance.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
@@ -78,6 +82,12 @@ func (bal *Balancer) Run(config Config, runOptions RunOptions) (nextRunOptions R
 	if err != nil {
 		return
 	}
+	for _, srv := range bal.KeepServices {
+		err = srv.discoverMounts(&config.Client)
+		if err != nil {
+			return
+		}
+	}
 
 	if err = bal.CheckSanityEarly(&config.Client); err != nil {
 		return
@@ -238,20 +248,24 @@ func (bal *Balancer) GetCurrentState(c *arvados.Client, pageSize, bufs int) erro
 		wg.Add(1)
 		go func(srv *KeepService) {
 			defer wg.Done()
-			bal.logf("%s: retrieve index", srv)
-			idx, err := srv.Index(c, "")
-			if err != nil {
-				errs <- fmt.Errorf("%s: %v", srv, err)
-				return
-			}
-			if len(errs) > 0 {
-				// Some other goroutine encountered an
-				// error -- any further effort here
-				// will be wasted.
-				return
+			bal.logf("%s: retrieve indexes", srv)
+			for _, mount := range srv.mounts {
+				bal.logf("%s: retrieve index", mount)
+				idx, err := srv.IndexMount(c, mount.UUID, "")
+				if err != nil {
+					errs <- fmt.Errorf("%s: retrieve index: %v", mount, err)
+					return
+				}
+				if len(errs) > 0 {
+					// Some other goroutine encountered an
+					// error -- any further effort here
+					// will be wasted.
+					return
+				}
+				bal.logf("%s: add %d replicas to map", mount, len(idx))
+				bal.BlockStateMap.AddReplicas(mount, idx)
+				bal.logf("%s: done", mount)
 			}
-			bal.logf("%s: add %d replicas to map", srv, len(idx))
-			bal.BlockStateMap.AddReplicas(srv, idx)
 			bal.logf("%s: done", srv)
 		}(srv)
 	}
@@ -391,14 +405,50 @@ var changeName = map[int]string{
 // block, and makes the appropriate ChangeSet calls.
 func (bal *Balancer) balanceBlock(blkid arvados.SizedDigest, blk *BlockState) {
 	debugf("balanceBlock: %v %+v", blkid, blk)
+
+	// A slot is somewhere a replica could potentially be trashed
+	// from, pulled from, or pulled to. Each KeepService gets
+	// either one empty slot, or one or more non-empty slots.
+	type slot struct {
+		srv  *KeepService // never nil
+		repl *Replica     // nil if none found
+	}
+
+	// First, we build an ordered list of all slots worth
+	// considering (including all slots where replicas have been
+	// found, as well as all of the optimal slots for this block).
+	// Then, when we consider each slot in that order, we will
+	// have all of the information we need to make a decision
+	// about that slot.
+
 	uuids := keepclient.NewRootSorter(bal.serviceRoots, string(blkid[:32])).GetSortedRoots()
-	hasRepl := make(map[string]Replica, len(bal.serviceRoots))
-	for _, repl := range blk.Replicas {
-		hasRepl[repl.UUID] = repl
-		// TODO: when multiple copies are on one server, use
-		// the oldest one that doesn't have a timestamp
-		// collision with other replicas.
+	rendezvousOrder := make(map[*KeepService]int, len(uuids))
+	slots := make([]slot, len(uuids))
+	for i, uuid := range uuids {
+		srv := bal.KeepServices[uuid]
+		rendezvousOrder[srv] = i
+		slots[i].srv = srv
+	}
+	for ri := range blk.Replicas {
+		// TODO: when multiple copies are on one server,
+		// prefer one on a readonly mount, or the oldest one
+		// that doesn't have a timestamp collision with other
+		// replicas.
+		repl := &blk.Replicas[ri]
+		srv := repl.KeepService
+		slotIdx := rendezvousOrder[srv]
+		if slots[slotIdx].repl != nil {
+			// Additional replicas on a single server are
+			// considered non-optimal. Within this
+			// category, we don't try to optimize layout:
+			// we just say the optimal order is the order
+			// we encounter them.
+			slotIdx = len(slots)
+			slots = append(slots, slot{srv: srv})
+		}
+		slots[slotIdx].repl = repl
 	}
+
 	// number of replicas already found in positions better than
 	// the position we're contemplating now.
 	reportedBestRepl := 0
@@ -414,12 +464,11 @@ func (bal *Balancer) balanceBlock(blkid arvados.SizedDigest, blk *BlockState) {
 	// requested on rendezvous positions M<N will be successful.)
 	pulls := 0
 	var changes []string
-	for _, uuid := range uuids {
+	for _, slot := range slots {
 		change := changeNone
-		srv := bal.KeepServices[uuid]
+		srv, repl := slot.srv, slot.repl
 		// TODO: request a Touch if Mtime is duplicated.
-		repl, ok := hasRepl[srv.UUID]
-		if ok {
+		if repl != nil {
 			// This service has a replica. We should
 			// delete it if [1] we already have enough
 			// distinct replicas in better rendezvous
@@ -427,6 +476,7 @@ func (bal *Balancer) balanceBlock(blkid arvados.SizedDigest, blk *BlockState) {
 			// distinct from all of the better replicas'
 			// Mtimes.
 			if !srv.ReadOnly &&
+				!repl.KeepMount.ReadOnly &&
 				repl.Mtime < bal.MinMtime &&
 				len(uniqueBestRepl) >= blk.Desired &&
 				!uniqueBestRepl[repl.Mtime] {
@@ -455,7 +505,11 @@ func (bal *Balancer) balanceBlock(blkid arvados.SizedDigest, blk *BlockState) {
 			change = changePull
 		}
 		if bal.Dumper != nil {
-			changes = append(changes, fmt.Sprintf("%s:%d=%s,%d", srv.ServiceHost, srv.ServicePort, changeName[change], repl.Mtime))
+			var mtime int64
+			if repl != nil {
+				mtime = repl.Mtime
+			}
+			changes = append(changes, fmt.Sprintf("%s:%d=%s,%d", srv.ServiceHost, srv.ServicePort, changeName[change], mtime))
 		}
 	}
 	if bal.Dumper != nil {