@Override
    public void awaitShutdown() {
        Instant deadline = clock().instant().plus(Duration.ofMinutes(1));
        super.awaitShutdown();
        try {
            long remainder = Duration.between(clock().instant(), deadline).toMillis();
            if (deploymentExecutor.isShutdown()) return;

            // Give deployments in progress some time to complete
            if (remainder < 0 || !deploymentExecutor.awaitTermination(remainder, TimeUnit.MILLISECONDS)) {
                log.log(Level.WARNING, "Failed to shut down deployment executor within deadline");
                deploymentExecutor.shutdownNow();
            }
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
Returns the last time application was deployed. Epoch is returned if the application has never been deployed.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/ApplicationMaintainer.java