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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.maintenance;
import java.util.logging.Level;
import com.yahoo.vespa.hosted.provision.Node;
import com.yahoo.vespa.hosted.provision.NodeRepository;
import com.yahoo.vespa.hosted.provision.lb.LoadBalancer;
import com.yahoo.vespa.hosted.provision.lb.LoadBalancer.State;
import com.yahoo.vespa.hosted.provision.lb.LoadBalancerId;
import com.yahoo.vespa.hosted.provision.lb.LoadBalancerService;
import com.yahoo.vespa.hosted.provision.persistence.CuratorDatabaseClient;
import java.time.Duration;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;
import java.util.stream.Collectors;
/**
* Periodically expire load balancers.
*
* Load balancers expire from the following states:
*
* {@link LoadBalancer.State#inactive}: An application is removed and load balancers are deactivated.
* {@link LoadBalancer.State#reserved}: An prepared application is never successfully activated, thus never activating
* any prepared load balancers.
*
* @author mpolden
*/
public class LoadBalancerExpirer extends Maintainer {
private static final Duration reservedExpiry = Duration.ofHours(1);
private static final Duration inactiveExpiry = Duration.ofHours(1);
private final LoadBalancerService service;
private final CuratorDatabaseClient db;
LoadBalancerExpirer(NodeRepository nodeRepository, Duration interval, LoadBalancerService service) {
super(nodeRepository, interval);
this.service = Objects.requireNonNull(service, "service must be non-null");
this.db = nodeRepository.database();
}
@Override
protected void maintain() {
expireReserved();
removeInactive();
pruneReals();
}
/** Move reserved load balancer that have expired to inactive */
private void expireReserved() {
var now = nodeRepository().clock().instant();
withLoadBalancersIn(State.reserved, lb -> {
var gracePeriod = now.minus(reservedExpiry);
if (!lb.changedAt().isBefore(gracePeriod)) return; // Should not move to inactive yet
db.writeLoadBalancer(lb.with(State.inactive, now));
});
}
/** Deprovision inactive load balancers that have expired */
private void removeInactive() {
var failed = new ArrayList<LoadBalancerId>();
var lastException = new AtomicReference<Exception>();
var now = nodeRepository().clock().instant();
withLoadBalancersIn(State.inactive, lb -> {
var gracePeriod = now.minus(inactiveExpiry);
if (!lb.changedAt().isBefore(gracePeriod)) return; // Should not be removed yet
if (!allocatedNodes(lb.id()).isEmpty()) return; // Still has nodes, do not remove
try {
service.remove(lb.id().application(), lb.id().cluster());
db.removeLoadBalancer(lb.id());
} catch (Exception e){
failed.add(lb.id());
lastException.set(e);
}
});
if (!failed.isEmpty()) {
log.log(LogLevel.WARNING, String.format("Failed to remove %d load balancers: %s, retrying in %s",
failed.size(),
failed.stream()
.map(LoadBalancerId::serializedForm)
.collect(Collectors.joining(", ")),
interval()),
lastException.get());
}
}
/** Remove reals from inactive load balancers */
private void pruneReals() {
var failed = new ArrayList<LoadBalancerId>();
var lastException = new AtomicReference<Exception>();
withLoadBalancersIn(State.inactive, lb -> {
var allocatedNodes = allocatedNodes(lb.id()).stream().map(Node::hostname).collect(Collectors.toSet());
var reals = new LinkedHashSet<>(lb.instance().reals());
// Remove any real no longer allocated to this application
reals.removeIf(real -> !allocatedNodes.contains(real.hostname().value()));
try {
service.create(lb.id().application(), lb.id().cluster(), reals, true);
db.writeLoadBalancer(lb.with(lb.instance().withReals(reals)));
} catch (Exception e) {
failed.add(lb.id());
lastException.set(e);
}
});
if (!failed.isEmpty()) {
log.log(LogLevel.WARNING, String.format("Failed to remove reals from %d load balancers: %s, retrying in %s",
failed.size(),
failed.stream()
.map(LoadBalancerId::serializedForm)
.collect(Collectors.joining(", ")),
interval()),
lastException.get());
}
}
/** Apply operation to all load balancers that exist in given state, while holding lock */
private void withLoadBalancersIn(LoadBalancer.State state, Consumer<LoadBalancer> operation) {
for (var id : db.readLoadBalancerIds()) {
try (var lock = db.lock(id.application())) {
var loadBalancer = db.readLoadBalancer(id);
if (loadBalancer.isEmpty()) continue; // Load balancer was removed during loop
if (loadBalancer.get().state() != state) continue; // Wrong state
operation.accept(loadBalancer.get());
}
}
}
private List<Node> allocatedNodes(LoadBalancerId loadBalancer) {
return nodeRepository().list().owner(loadBalancer.application()).cluster(loadBalancer.cluster()).asList();
}
}
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