use uuids for peers

2025-10-29 04:57:48 +01:00 · 2024-06-22 16:16:27 +02:00
parent 386bd14458
commit e3dc6e2a71
21 changed files with 134 additions and 120 deletions
--- a/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/DirectoryConflictResolver.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/DirectoryConflictResolver.java
@@ -4,12 +4,12 @@ import com.usatiuk.dhfs.storage.SerializationHelper;
 import com.usatiuk.dhfs.storage.objects.jrepository.JObject;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.ConflictResolver;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.ObjectMetadata;
+import com.usatiuk.dhfs.storage.objects.repository.distributed.PersistentRemoteHostsService;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.RemoteObjectServiceClient;
 import io.quarkus.logging.Log;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.NotImplementedException;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.util.LinkedHashMap;
 import java.util.Objects;
@@ -17,14 +17,14 @@ import java.util.UUID;

@ApplicationScoped
 public class DirectoryConflictResolver implements ConflictResolver {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;

    @Inject
    RemoteObjectServiceClient remoteObjectServiceClient;

    @Override
-    public ConflictResolutionResult resolve(String conflictHost, JObject<?> ours) {
+    public ConflictResolutionResult resolve(UUID conflictHost, JObject<?> ours) {
        var theirsData = remoteObjectServiceClient.getSpecificObject(conflictHost, ours.getName());

        if (!ours.isOf(Directory.class))
@@ -52,7 +52,7 @@ public class DirectoryConflictResolver implements ConflictResolver {

            Directory first;
            Directory second;
-            String otherHostname;
+            UUID otherHostname;
            if (oursDir.getMtime() >= theirsDir.getMtime()) {
                first = oursDir;
                second = theirsDir;
@@ -60,7 +60,7 @@ public class DirectoryConflictResolver implements ConflictResolver {
            } else {
                second = oursDir;
                first = theirsDir;
-                otherHostname = selfname;
+                otherHostname = persistentRemoteHostsService.getSelfUuid();
            }

            mergedChildren.putAll(first.getChildren());
@@ -85,15 +85,15 @@ public class DirectoryConflictResolver implements ConflictResolver {
            newMetadata = new ObjectMetadata(ours.getName(), oursHeader.getConflictResolver(), m.getType());

            for (var entry : oursHeader.getChangelog().getEntriesList()) {
-                newMetadata.getChangelog().put(entry.getHost(), entry.getVersion());
+                newMetadata.getChangelog().put(UUID.fromString(entry.getHost()), entry.getVersion());
            }
            for (var entry : theirsHeader.getChangelog().getEntriesList()) {
-                newMetadata.getChangelog().merge(entry.getHost(), entry.getVersion(), Long::max);
+                newMetadata.getChangelog().merge(UUID.fromString(entry.getHost()), entry.getVersion(), Long::max);
            }

            boolean wasChanged = mergedChildren.size() != first.getChildren().size();
            if (wasChanged) {
-                newMetadata.getChangelog().merge(selfname, 1L, Long::sum);
+                newMetadata.getChangelog().merge(persistentRemoteHostsService.getSelfUuid(), 1L, Long::sum);
            }

            newMtime = first.getMtime();
--- a/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/NoOpConflictResolver.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/NoOpConflictResolver.java
@@ -4,10 +4,12 @@ import com.usatiuk.dhfs.storage.objects.jrepository.JObject;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.ConflictResolver;
 import jakarta.enterprise.context.ApplicationScoped;

+import java.util.UUID;
+
@ApplicationScoped
 public class NoOpConflictResolver implements ConflictResolver {
    @Override
-    public ConflictResolutionResult resolve(String conflictHost, JObject<?> conflictSource) {
+    public ConflictResolutionResult resolve(UUID conflictHost, JObject<?> conflictSource) {
        // Maybe check types?
        return ConflictResolutionResult.RESOLVED;
    }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/NotImplementedConflictResolver.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/files/objects/NotImplementedConflictResolver.java
@@ -5,10 +5,12 @@ import com.usatiuk.dhfs.storage.objects.repository.distributed.ConflictResolver;
 import jakarta.enterprise.context.ApplicationScoped;
 import org.apache.commons.lang3.NotImplementedException;

+import java.util.UUID;
+
@ApplicationScoped
 public class NotImplementedConflictResolver implements ConflictResolver {
    @Override
-    public ConflictResolutionResult resolve(String conflictHost, JObject<?> conflictSource) {
+    public ConflictResolutionResult resolve(UUID conflictHost, JObject<?> conflictSource) {
        throw new NotImplementedException();
    }
 }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObject.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObject.java
@@ -8,18 +8,19 @@ import org.apache.commons.lang3.NotImplementedException;

 import java.io.Serializable;
 import java.util.Objects;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantReadWriteLock;

 public class JObject<T extends JObjectData> implements Serializable {
    // Create a new object
-    protected JObject(JObjectResolver resolver, String name, String conflictResolver, String selfname, T obj) {
+    protected JObject(JObjectResolver resolver, String name, String conflictResolver, UUID selfUuid, T obj) {
        _resolver = resolver;
        _metaPart = new ObjectMetadata(name, conflictResolver, obj.getClass());
        _dataPart.set(obj);
        // FIXME:?
        if (!obj.assumeUnique())
-            _metaPart.bumpVersion(selfname);
+            _metaPart.bumpVersion(selfUuid);
    }

    // Create an object from existing metadata
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObjectManagerImpl.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObjectManagerImpl.java
@@ -3,6 +3,7 @@ package com.usatiuk.dhfs.storage.objects.jrepository;
 import com.google.protobuf.ByteString;
 import com.usatiuk.dhfs.storage.SerializationHelper;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.ObjectMetadata;
+import com.usatiuk.dhfs.storage.objects.repository.distributed.PersistentRemoteHostsService;
 import com.usatiuk.dhfs.storage.objects.repository.persistence.ObjectPersistentStore;
 import io.grpc.Status;
 import io.grpc.StatusRuntimeException;
@@ -12,7 +13,6 @@ import io.quarkus.runtime.Startup;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import lombok.Getter;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.SoftReference;
@@ -24,15 +24,15 @@ public class JObjectManagerImpl implements JObjectManager {
    @Inject
    ObjectPersistentStore objectPersistentStore;

-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
-
    @Inject
    JObjectResolver jObjectResolver;

    @Inject
    JObjectWriteback jObjectWriteback;

+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;
+
    private static class NamedSoftReference extends SoftReference<JObject<?>> {
        public NamedSoftReference(JObject<?> target, ReferenceQueue<JObject<?>> q) {
            super(target, q);
@@ -176,7 +176,7 @@ public class JObjectManagerImpl implements JObjectManager {
                return (JObject<D>) inMap;
            } else {
                var created = new JObject<D>(jObjectResolver, object.getName(),
-                        object.getConflictResolver().getName(), selfname, object);
+                        object.getConflictResolver().getName(), persistentRemoteHostsService.getSelfUuid(), object);
                _map.put(object.getName(), new NamedSoftReference(created, _refQueue));
                created.runWriteLockedMeta((m, d, b) -> {
                    jObjectResolver.notifyWrite(created);
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObjectResolver.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/jrepository/JObjectResolver.java
@@ -2,6 +2,7 @@ package com.usatiuk.dhfs.storage.objects.jrepository;

 import com.usatiuk.dhfs.storage.SerializationHelper;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.InvalidationQueueService;
+import com.usatiuk.dhfs.storage.objects.repository.distributed.PersistentRemoteHostsService;
 import com.usatiuk.dhfs.storage.objects.repository.distributed.RemoteObjectServiceClient;
 import com.usatiuk.dhfs.storage.objects.repository.persistence.ObjectPersistentStore;
 import io.grpc.Status;
@@ -9,7 +10,6 @@ import io.grpc.StatusRuntimeException;
 import io.quarkus.logging.Log;
 import jakarta.inject.Inject;
 import jakarta.inject.Singleton;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.util.Optional;

@@ -27,8 +27,8 @@ public class JObjectResolver {
    @Inject
    JObjectWriteback jObjectWriteback;

-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;

    public <T extends JObjectData> Optional<T> resolveDataLocal(JObject<T> jObject) {
        jObject.assertRWLock();
@@ -73,7 +73,7 @@ public class JObjectResolver {
    public void bumpVersionSelf(JObject<?> self) {
        self.assertRWLock();
        self.runWriteLockedMeta((m, bump, invalidate) -> {
-            m.bumpVersion(selfname);
+            m.bumpVersion(persistentRemoteHostsService.getSelfUuid());
            return null;
        });
    }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/ConflictResolver.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/ConflictResolver.java
@@ -1,8 +1,9 @@
 package com.usatiuk.dhfs.storage.objects.repository.distributed;

-import com.usatiuk.dhfs.objects.repository.distributed.ObjectHeader;
 import com.usatiuk.dhfs.storage.objects.jrepository.JObject;

+import java.util.UUID;
+
 public interface ConflictResolver {
    enum ConflictResolutionResult {
        RESOLVED,
@@ -10,5 +11,5 @@ public interface ConflictResolver {
    }

    ConflictResolutionResult
-    resolve(String conflictHost, JObject<?> conflictSource);
+    resolve(UUID conflictHost, JObject<?> conflictSource);
 }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/HostInfo.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/HostInfo.java
@@ -6,10 +6,11 @@ import lombok.Getter;
 import lombok.Setter;

 import java.io.Serializable;
+import java.util.UUID;

@Getter
 public class HostInfo implements Serializable {
-    private final String _name;
+    private final UUID _uuid;

    @Setter
    private String _addr;
@@ -17,10 +18,10 @@ public class HostInfo implements Serializable {
    private Integer _port;

    @JsonbCreator
-    public HostInfo(@JsonbProperty("_name") String name,
-                    @JsonbProperty("_addr") String addr,
-                    @JsonbProperty("_port") Integer port) {
-        _name = name;
+    public HostInfo(@JsonbProperty("uuid") String uuid,
+                    @JsonbProperty("addr") String addr,
+                    @JsonbProperty("port") Integer port) {
+        _uuid = UUID.fromString(uuid);
        _addr = addr;
        _port = port;
    }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/InvalidationQueueService.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/InvalidationQueueService.java
@@ -18,7 +18,7 @@ public class InvalidationQueueService {
    @Inject
    RemoteObjectServiceClient remoteObjectServiceClient;

-    private Map<String, SequencedSet<String>> _hostToInvObj = new LinkedHashMap<>();
+    private Map<UUID, SequencedSet<String>> _hostToInvObj = new LinkedHashMap<>();

    private Thread _senderThread;

@@ -34,13 +34,13 @@ public class InvalidationQueueService {
        _senderThread.join();
    }

-    private SequencedSet<String> getSetForHost(String host) {
+    private SequencedSet<String> getSetForHost(UUID host) {
        synchronized (this) {
            return _hostToInvObj.computeIfAbsent(host, k -> new LinkedHashSet<>());
        }
    }

-    public Map<String, SequencedSet<String>> pullAll() throws InterruptedException {
+    public Map<UUID, SequencedSet<String>> pullAll() throws InterruptedException {
        synchronized (this) {
            while (_hostToInvObj.isEmpty())
                this.wait();
@@ -103,7 +103,7 @@ public class InvalidationQueueService {
        }
    }

-    public void pushInvalidationToOne(String host, String name) {
+    public void pushInvalidationToOne(UUID host, String name) {
        synchronized (this) {
            getSetForHost(host).add(name);
            this.notifyAll();
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/ObjectMetadata.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/ObjectMetadata.java
@@ -5,11 +5,11 @@ import com.usatiuk.dhfs.objects.repository.distributed.ObjectChangelogEntry;
 import com.usatiuk.dhfs.objects.repository.distributed.ObjectHeader;
 import com.usatiuk.dhfs.storage.objects.jrepository.JObjectData;
 import lombok.Getter;
-import org.eclipse.microprofile.config.ConfigProvider;

 import java.io.Serializable;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.UUID;

 public class ObjectMetadata implements Serializable {
    public ObjectMetadata(String name, String conflictResolver, Class<? extends JObjectData> type) {
@@ -28,10 +28,10 @@ public class ObjectMetadata implements Serializable {
    private final Class<? extends JObjectData> _type;

    @Getter
-    private final Map<String, Long> _remoteCopies = new LinkedHashMap<>();
+    private final Map<UUID, Long> _remoteCopies = new LinkedHashMap<>();

    @Getter
-    private final Map<String, Long> _changelog = new LinkedHashMap<>();
+    private final Map<UUID, Long> _changelog = new LinkedHashMap<>();

    public Long getOurVersion() {
        return _changelog.values().stream().reduce(0L, Long::sum);
@@ -42,14 +42,15 @@ public class ObjectMetadata implements Serializable {
        return Math.max(getOurVersion(), _remoteCopies.values().stream().max(Long::compareTo).get());
    }

-    public void bumpVersion(String selfname) {
-        _changelog.merge(selfname, 1L, Long::sum);
+    public void bumpVersion(UUID selfUuid) {
+        _changelog.merge(selfUuid, 1L, Long::sum);
    }

    public ObjectChangelog toRpcChangelog() {
        var changelogBuilder = ObjectChangelog.newBuilder();
        for (var m : getChangelog().entrySet()) {
-            changelogBuilder.addEntries(ObjectChangelogEntry.newBuilder().setHost(m.getKey()).setVersion(m.getValue()).build());
+            changelogBuilder.addEntries(ObjectChangelogEntry.newBuilder()
+                    .setHost(m.getKey().toString()).setVersion(m.getValue()).build());
        }
        return changelogBuilder.build();
    }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/PersistentRemoteHostsData.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/PersistentRemoteHostsData.java
@@ -4,8 +4,12 @@ import lombok.Getter;

 import java.io.Serializable;
 import java.util.HashMap;
+import java.util.UUID;

 public class PersistentRemoteHostsData implements Serializable {
    @Getter
-    private final HashMap<String, HostInfo> _remoteHosts = new HashMap<>();
+    private final HashMap<UUID, HostInfo> _remoteHosts = new HashMap<>();
+
+    @Getter
+    private final UUID _selfUuid = UUID.randomUUID();
 }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/PersistentRemoteHostsService.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/PersistentRemoteHostsService.java
@@ -14,12 +14,10 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.List;
+import java.util.UUID;

@ApplicationScoped
 public class PersistentRemoteHostsService {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
-
    @ConfigProperty(name = "dhfs.objects.distributed.root")
    String dataRoot;

@@ -27,6 +25,8 @@ public class PersistentRemoteHostsService {

    private PersistentRemoteHosts _persistentData = new PersistentRemoteHosts();

+    private UUID _selfUuid;
+
    void init(@Observes @Priority(300) StartupEvent event) throws IOException {
        Paths.get(dataRoot).toFile().mkdirs();
        Log.info("Initializing with root " + dataRoot);
@@ -34,6 +34,8 @@ public class PersistentRemoteHostsService {
            Log.info("Reading hosts");
            _persistentData = SerializationHelper.deserialize(Files.readAllBytes(Paths.get(dataRoot).resolve(dataFileName)));
        }
+        _selfUuid = _persistentData.runReadLocked(PersistentRemoteHostsData::getSelfUuid);
+        Log.info("Self uuid is: " + _selfUuid.toString());
    }

    void shutdown(@Observes @Priority(300) ShutdownEvent event) throws IOException {
@@ -42,7 +44,13 @@ public class PersistentRemoteHostsService {
        Log.info("Shutdown");
    }

-    public HostInfo getInfo(String name) {
+    public UUID getSelfUuid() {
+        if (_selfUuid == null)
+            throw new IllegalStateException();
+        else return _selfUuid;
+    }
+
+    public HostInfo getInfo(UUID name) {
        return _persistentData.runReadLocked(data -> {
            return data.getRemoteHosts().get(name);
        });
@@ -56,7 +64,7 @@ public class PersistentRemoteHostsService {

    public void addHost(HostInfo hostInfo) {
        _persistentData.runWriteLocked(d -> {
-            d.getRemoteHosts().put(hostInfo.getName(), hostInfo);
+            d.getRemoteHosts().put(hostInfo.getUuid(), hostInfo);
            return null;
        });
    }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteHostManager.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteHostManager.java
@@ -15,7 +15,6 @@ import jakarta.annotation.Priority;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.enterprise.event.Observes;
 import jakarta.inject.Inject;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.io.IOException;
 import java.util.*;
@@ -23,9 +22,6 @@ import java.util.concurrent.TimeUnit;

@ApplicationScoped
 public class RemoteHostManager {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
-
    @Inject
    PersistentRemoteHostsService persistentRemoteHostsService;

@@ -45,20 +41,20 @@ public class RemoteHostManager {
    public void tryConnectAll() {
        for (var host : persistentRemoteHostsService.getHosts()) {
            var shouldTry = _transientPeersState.runReadLocked(d -> {
-                var s = d.getStates().get(host.getName());
+                var s = d.getStates().get(host.getUuid());
                if (s == null) return true;
                return !s.getState().equals(TransientPeersStateData.TransientPeerState.ConnectionState.REACHABLE);
            });
            if (shouldTry) {
-                Log.info("Trying to connect to " + host.getName());
+                Log.info("Trying to connect to " + host.getUuid());
                if (reachable(host)) {
-                    handleConnectionSuccess(host.getName());
+                    handleConnectionSuccess(host.getUuid());
                }
            }
        }
    }

-    public void handleConnectionSuccess(String host) {
+    public void handleConnectionSuccess(UUID host) {
        if (_transientPeersState.runReadLocked(d -> d.getStates().getOrDefault(
                host, new TransientPeersStateData.TransientPeerState(TransientPeersStateData.TransientPeerState.ConnectionState.NOT_SEEN)
        )).getState().equals(TransientPeersStateData.TransientPeerState.ConnectionState.REACHABLE)) return;
@@ -72,7 +68,7 @@ public class RemoteHostManager {
        syncHandler.doInitialResync(host);
    }

-    public void handleConnectionError(String host) {
+    public void handleConnectionError(UUID host) {
        Log.info("Lost connection to " + host);
        _transientPeersState.runWriteLocked(d -> {
            d.getStates().putIfAbsent(host, new TransientPeersStateData.TransientPeerState());
@@ -108,30 +104,30 @@ public class RemoteHostManager {
    private boolean reachable(HostInfo hostInfo) {
        try {
            return withClient(hostInfo.getAddr(), hostInfo.getPort(), Optional.of(5000L /*ms*/), c -> {
-                var ret = c.ping(PingRequest.newBuilder().setSelfname(selfname).build());
-                if (!ret.getSelfname().equals(hostInfo.getName())) {
-                    throw new IllegalStateException("Ping selfname returned " + ret.getSelfname() + " but expected " + hostInfo.getName());
+                var ret = c.ping(PingRequest.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString()).build());
+                if (!UUID.fromString(ret.getSelfUuid()).equals(hostInfo.getUuid())) {
+                    throw new IllegalStateException("Ping selfUuid returned " + ret.getSelfUuid() + " but expected " + hostInfo.getUuid());
                }
                return true;
            });
        } catch (Exception ignored) {
-            Log.info("Host " + hostInfo.getName() + " is unreachable: " + ignored.getMessage() + " " + ignored.getCause());
+            Log.info("Host " + hostInfo.getUuid() + " is unreachable: " + ignored.getMessage() + " " + ignored.getCause());
            return false;
        }
    }

-    public boolean reachable(String host) {
+    public boolean reachable(UUID host) {
        return reachable(persistentRemoteHostsService.getInfo(host));
    }

-    public <R> R withClientAny(Collection<String> targets, ClientFunction<R> fn) {
+    public <R> R withClientAny(Collection<UUID> targets, ClientFunction<R> fn) {
        var shuffledList = new ArrayList<>(targets);
        Collections.shuffle(shuffledList);
-        for (String target : shuffledList) {
+        for (UUID target : shuffledList) {
            var hostinfo = persistentRemoteHostsService.getInfo(target);

            boolean shouldTry = _transientPeersState.runReadLocked(d -> {
-                var res = d.getStates().get(hostinfo.getName());
+                var res = d.getStates().get(hostinfo.getUuid());
                if (res == null) return true;
                return res.getState() == TransientPeersStateData.TransientPeerState.ConnectionState.REACHABLE;
            });
@@ -142,26 +138,26 @@ public class RemoteHostManager {
                return withClient(hostinfo.getAddr(), hostinfo.getPort(), Optional.empty(), fn);
            } catch (StatusRuntimeException e) {
                if (e.getStatus().equals(Status.UNAVAILABLE)) {
-                    Log.info("Host " + hostinfo.getName() + " is unreachable: " + e.getMessage());
-                    handleConnectionError(hostinfo.getName());
+                    Log.info("Host " + hostinfo.getUuid() + " is unreachable: " + e.getMessage());
+                    handleConnectionError(hostinfo.getUuid());
                } else throw e;
            }
        }
        throw new IllegalStateException("No reachable targets!");
    }

-    public <R> R withClient(String target, ClientFunction<R> fn) {
+    public <R> R withClient(UUID target, ClientFunction<R> fn) {
        var hostinfo = persistentRemoteHostsService.getInfo(target);
        return withClient(hostinfo.getAddr(), hostinfo.getPort(), Optional.empty(), fn);
    }

-    public List<String> getAvailableHosts() {
+    public List<UUID> getAvailableHosts() {
        return _transientPeersState.runReadLocked(d -> d.getStates().entrySet().stream()
                .filter(e -> e.getValue().getState().equals(TransientPeersStateData.TransientPeerState.ConnectionState.REACHABLE))
                .map(Map.Entry::getKey).toList());
    }

-    public List<String> getSeenHosts() {
+    public List<UUID> getSeenHosts() {
        return _transientPeersState.runReadLocked(d -> d.getStates().entrySet().stream()
                .filter(e -> !e.getValue().getState().equals(TransientPeersStateData.TransientPeerState.ConnectionState.NOT_SEEN))
                .map(Map.Entry::getKey).toList());
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteObjectServiceClient.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteObjectServiceClient.java
@@ -9,15 +9,15 @@ import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.NotImplementedException;
 import org.apache.commons.lang3.tuple.Pair;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.util.List;
 import java.util.Map;
+import java.util.UUID;

@ApplicationScoped
 public class RemoteObjectServiceClient {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;

    @Inject
    RemoteHostManager remoteHostManager;
@@ -25,9 +25,9 @@ public class RemoteObjectServiceClient {
    @Inject
    JObjectManager jObjectManager;

-    public Pair<ObjectHeader, ByteString> getSpecificObject(String host, String name) {
+    public Pair<ObjectHeader, ByteString> getSpecificObject(UUID host, String name) {
        return remoteHostManager.withClient(host, client -> {
-            var reply = client.getObject(GetObjectRequest.newBuilder().setSelfname(selfname).setName(name).build());
+            var reply = client.getObject(GetObjectRequest.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString()).setName(name).build());
            return Pair.of(reply.getObject().getHeader(), reply.getObject().getContent());
        });
    }
@@ -41,10 +41,10 @@ public class RemoteObjectServiceClient {
        });

        return remoteHostManager.withClientAny(targets, client -> {
-            var reply = client.getObject(GetObjectRequest.newBuilder().setSelfname(selfname).setName(jObject.getName()).build());
+            var reply = client.getObject(GetObjectRequest.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString()).setName(jObject.getName()).build());

            var receivedSelfVer = reply.getObject().getHeader().getChangelog()
-                    .getEntriesList().stream().filter(p -> p.getHost().equals(selfname))
+                    .getEntriesList().stream().filter(p -> p.getHost().equals(persistentRemoteHostsService.getSelfUuid().toString()))
                    .findFirst().map(ObjectChangelogEntry::getVersion).orElse(0L);

            var receivedTotalVer = reply.getObject().getHeader().getChangelog().getEntriesList()
@@ -53,7 +53,7 @@ public class RemoteObjectServiceClient {
            return jObject.runWriteLockedMeta((md, b, v) -> {
                var outdated =
                        (md.getOurVersion() > receivedTotalVer)
-                                || (md.getChangelog().get(selfname) > receivedSelfVer);
+                                || (md.getChangelog().get(persistentRemoteHostsService.getSelfUuid()) > receivedSelfVer);

                if (outdated) {
                    Log.error("Race when trying to fetch");
@@ -64,15 +64,15 @@ public class RemoteObjectServiceClient {
        });
    }

-    public IndexUpdatePush getIndex(String host) {
+    public IndexUpdatePush getIndex(UUID host) {
        return remoteHostManager.withClient(host, client -> {
-            var req = GetIndexRequest.newBuilder().setSelfname(selfname).build();
+            var req = GetIndexRequest.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString()).build();
            return client.getIndex(req);
        });
    }

-    public List<IndexUpdateError> notifyUpdate(String host, List<String> names) {
-        var builder = IndexUpdatePush.newBuilder().setSelfname(selfname);
+    public List<IndexUpdateError> notifyUpdate(UUID host, List<String> names) {
+        var builder = IndexUpdatePush.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString());
        for (var v : names) {
            var obj = jObjectManager.get(v);
            if (obj.isEmpty()) continue;
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteObjectServiceServer.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/RemoteObjectServiceServer.java
@@ -12,14 +12,12 @@ import io.smallrye.common.annotation.Blocking;
 import io.smallrye.mutiny.Uni;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.tuple.Pair;
-import org.eclipse.microprofile.config.inject.ConfigProperty;
+
+import java.util.UUID;

 // Note: RunOnVirtualThread hangs somehow
@GrpcService
 public class RemoteObjectServiceServer implements DhfsObjectSyncGrpc {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
-
    @Inject
    SyncHandler syncHandler;

@@ -29,12 +27,15 @@ public class RemoteObjectServiceServer implements DhfsObjectSyncGrpc {
    @Inject
    RemoteHostManager remoteHostManager;

+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;
+
    @Override
    @Blocking
    public Uni<GetObjectReply> getObject(GetObjectRequest request) {
-        if (request.getSelfname().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
+        if (request.getSelfUuid().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);

-        remoteHostManager.handleConnectionSuccess(request.getSelfname());
+        remoteHostManager.handleConnectionSuccess(UUID.fromString(request.getSelfUuid()));

        Log.info("<-- getObject: " + request.getName());

@@ -48,11 +49,11 @@ public class RemoteObjectServiceServer implements DhfsObjectSyncGrpc {
    @Override
    @Blocking
    public Uni<IndexUpdatePush> getIndex(GetIndexRequest request) {
-        if (request.getSelfname().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
-        remoteHostManager.handleConnectionSuccess(request.getSelfname());
+        if (request.getSelfUuid().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
+        remoteHostManager.handleConnectionSuccess(UUID.fromString(request.getSelfUuid()));

        Log.info("<-- getIndex: ");
-        var builder = IndexUpdatePush.newBuilder().setSelfname(selfname);
+        var builder = IndexUpdatePush.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString());

        var objs = jObjectManager.find("");

@@ -68,8 +69,8 @@ public class RemoteObjectServiceServer implements DhfsObjectSyncGrpc {
    @Override
    @Blocking
    public Uni<IndexUpdateReply> indexUpdate(IndexUpdatePush request) {
-        if (request.getSelfname().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
-        remoteHostManager.handleConnectionSuccess(request.getSelfname());
+        if (request.getSelfUuid().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
+        remoteHostManager.handleConnectionSuccess(UUID.fromString(request.getSelfUuid()));

 //        Log.info("<-- indexUpdate: " + request.getHeader().getName());
        return Uni.createFrom().item(syncHandler.handleRemoteUpdate(request));
@@ -78,9 +79,9 @@ public class RemoteObjectServiceServer implements DhfsObjectSyncGrpc {
    @Override
    @Blocking
    public Uni<PingReply> ping(PingRequest request) {
-        if (request.getSelfname().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
-        remoteHostManager.handleConnectionSuccess(request.getSelfname());
+        if (request.getSelfUuid().isBlank()) throw new StatusRuntimeException(Status.INVALID_ARGUMENT);
+        remoteHostManager.handleConnectionSuccess(UUID.fromString(request.getSelfUuid()));

-        return Uni.createFrom().item(PingReply.newBuilder().setSelfname(selfname).build());
+        return Uni.createFrom().item(PingReply.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString()).build());
    }
 }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/SyncHandler.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/SyncHandler.java
@@ -11,15 +11,12 @@ import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.enterprise.inject.Instance;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.NotImplementedException;
-import org.eclipse.microprofile.config.inject.ConfigProperty;

 import java.util.Objects;
+import java.util.UUID;

@ApplicationScoped
 public class SyncHandler {
-    @ConfigProperty(name = "dhfs.objects.distributed.selfname")
-    String selfname;
-
    @Inject
    JObjectManager jObjectManager;

@@ -35,7 +32,10 @@ public class SyncHandler {
    @Inject
    Instance<ConflictResolver> conflictResolvers;

-    public void doInitialResync(String host) {
+    @Inject
+    PersistentRemoteHostsService persistentRemoteHostsService;
+
+    public void doInitialResync(UUID host) {
        var got = remoteObjectServiceClient.getIndex(host);
        handleRemoteUpdate(got);
        // Push our index to the other peer too, as they might not request it if
@@ -50,7 +50,7 @@ public class SyncHandler {
        }
    }

-    private void handleOneUpdate(String from, ObjectHeader header) {
+    private void handleOneUpdate(UUID from, ObjectHeader header) {
        JObject<?> found;
        try {
            found = jObjectManager.getOrPut(header.getName(), new ObjectMetadata(
@@ -63,7 +63,7 @@ public class SyncHandler {
        }

        var receivedSelfVer = header.getChangelog()
-                .getEntriesList().stream().filter(p -> p.getHost().equals(selfname))
+                .getEntriesList().stream().filter(p -> p.getHost().equals(persistentRemoteHostsService.getSelfUuid().toString()))
                .findFirst().map(ObjectChangelogEntry::getVersion).orElse(0L);

        var receivedTotalVer = header.getChangelog().getEntriesList()
@@ -76,13 +76,14 @@ public class SyncHandler {
                return false;
            }

-            if (md.getChangelog().getOrDefault(selfname, 0L) > receivedSelfVer) return true;
+            if (md.getChangelog().getOrDefault(persistentRemoteHostsService.getSelfUuid(), 0L) > receivedSelfVer)
+                return true;

            md.getRemoteCopies().put(from, receivedTotalVer);

            if (Objects.equals(md.getOurVersion(), receivedTotalVer)) {
                for (var e : header.getChangelog().getEntriesList()) {
-                    if (!Objects.equals(md.getChangelog().getOrDefault(e.getHost(), 0L),
+                    if (!Objects.equals(md.getChangelog().getOrDefault(UUID.fromString(e.getHost()), 0L),
                            e.getVersion())) return true;
                }
            }
@@ -101,9 +102,9 @@ public class SyncHandler {

            md.getChangelog().clear();
            for (var entry : header.getChangelog().getEntriesList()) {
-                md.getChangelog().put(entry.getHost(), entry.getVersion());
+                md.getChangelog().put(UUID.fromString(entry.getHost()), entry.getVersion());
            }
-            md.getChangelog().putIfAbsent(selfname, 0L);
+            md.getChangelog().putIfAbsent(persistentRemoteHostsService.getSelfUuid(), 0L);

            return false;
        });
@@ -121,11 +122,11 @@ public class SyncHandler {
    }

    public IndexUpdateReply handleRemoteUpdate(IndexUpdatePush request) {
-        var builder = IndexUpdateReply.newBuilder().setSelfname(selfname);
+        var builder = IndexUpdateReply.newBuilder().setSelfUuid(persistentRemoteHostsService.getSelfUuid().toString());

        for (var u : request.getHeaderList()) {
            try {
-                handleOneUpdate(request.getSelfname(), u);
+                handleOneUpdate(UUID.fromString(request.getSelfUuid()), u);
            } catch (Exception ex) {
                builder.addErrors(IndexUpdateError.newBuilder().setObjectName(u.getName()).setError(ex.toString()).build());
            }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/TransientPeersStateData.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/distributed/TransientPeersStateData.java
@@ -7,6 +7,7 @@ import lombok.Setter;

 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.UUID;

 public class TransientPeersStateData {

@@ -25,5 +26,5 @@ public class TransientPeersStateData {
    }

    @Getter
-    private final Map<String, TransientPeerState> _states = new LinkedHashMap<>();
+    private final Map<UUID, TransientPeerState> _states = new LinkedHashMap<>();
 }
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/persistence/FileObjectPersistentStore.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/persistence/FileObjectPersistentStore.java
@@ -78,7 +78,6 @@ public class FileObjectPersistentStore implements ObjectPersistentStore {
        }
    }

-    @Nonnull
    @Override
    public void writeObject(String name, ByteString data) {
        var file = Path.of(root, name);
@@ -99,7 +98,6 @@ public class FileObjectPersistentStore implements ObjectPersistentStore {
        }
    }

-    @Nonnull
    @Override
    public void deleteObject(String name) {
        var file = Path.of(root, name);
--- a/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/persistence/ObjectPersistentStore.java
+++ b/server/src/main/java/com/usatiuk/dhfs/storage/objects/repository/persistence/ObjectPersistentStore.java
@@ -13,8 +13,6 @@ public interface ObjectPersistentStore {

    @Nonnull
    ByteString readObject(String name);
-    @Nonnull
    void writeObject(String name, ByteString data);
-    @Nonnull
    void deleteObject(String name);
 }
--- a/server/src/main/proto/dhfs_objects_sync.proto
+++ b/server/src/main/proto/dhfs_objects_sync.proto
@@ -15,11 +15,11 @@ service DhfsObjectSyncGrpc {
 }

 message PingRequest {
-  string selfname = 1;
+  string selfUuid = 1;
 }

 message PingReply {
-  string selfname = 1;
+  string selfUuid = 1;
 }

 message ObjectChangelogEntry {
@@ -44,23 +44,23 @@ message ApiObject {
 }

 message GetObjectRequest {
-  string selfname = 10;
+  string selfUuid = 10;

  string name = 2;
 }

 message GetObjectReply {
-  string selfname = 10;
+  string selfUuid = 10;

  ApiObject object = 1;
 }

 message GetIndexRequest {
-  string selfname = 10;
+  string selfUuid = 10;
 }

 message IndexUpdatePush {
-  string selfname = 10;
+  string selfUuid = 10;

  repeated ObjectHeader header = 1;
 }
@@ -71,7 +71,7 @@ message IndexUpdateError {
 }

 message IndexUpdateReply {
-  string selfname = 10;
+  string selfUuid = 10;

  repeated IndexUpdateError errors = 1;
 }
--- a/server/src/main/resources/application.properties
+++ b/server/src/main/resources/application.properties
@@ -3,4 +3,3 @@ dhfs.objects.persistence.files.root=${HOME}/dhfs_data/dhfs_root
 dhfs.objects.distributed.root=${HOME}/dhfs_data/dhfs_root_d
 dhfs.fuse.root=${HOME}/dhfs_data/dhfs_fuse_root
 dhfs.storage.files.target_chunk_size=1048576
-dhfs.objects.distributed.selfname=thing1