### Concurrency and Burgers { #concurrency-and-burgers }

This idea of **asynchronous** code described above is also sometimes called **"concurrency"**. It is different from **"parallelism"**.

**Concurrency** and **parallelism** both relate to "different things happening more or less at the same time".

But the details between *concurrency* and *parallelism* are quite different.

Check the [release notes website](https://relnotes.k8s.io/?releaseVersions=1.15.0) for the complete changelog of notable features and fixes.




## Known Issues

- Concurrently joining control-plane nodes does not work as expected in kubeadm 1.15.0. The feature was planned for release in 1.15.0, but a fix may  come in a follow up patch release.

import java.time.Duration;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

- Fixed a data race that could occur when a single Go type was serialized to CBOR concurrently for the first time within a program. ([#129170](https://github.com/kubernetes/kubernetes/pull/129170), [@benluddy](https://github.com/benluddy)) [SIG API Machinery]

) {
	// used for storing the uploadID's parsed on concurrent HTTP requests for NewMultipart upload on the same object.
	testUploads := struct {
		sync.Mutex
		uploads []string
	}{}

	objectName := "test-object-new-multipart-parallel"
	var wg sync.WaitGroup
	for range 10 {
		wg.Add(1)
		// Initiate NewMultipart upload on the same object 10 times concurrrently.
		go func() {
			defer wg.Done()

<img src="/img/async/concurrent-burgers/concurrent-burgers-02.png" class="illustration">

El cajero dice algo al cocinero en la cocina para que sepan que tienen que preparar tus hamburguesas (aunque actualmente están preparando las de los clientes anteriores).

<img src="/img/async/concurrent-burgers/concurrent-burgers-03.png" class="illustration">

Pagas. 💸

El cajero te da el número de tu turno.

			// the concurrency make sure we choose only the "start"
			// concurrency to be equal to the lowest number of
			// local disks per server.
			for _, localDiskCount := range globalEndpoints.NLocalDisksPathsPerPool() {
				if localDiskCount < concurrency {
					concurrency = localDiskCount
				}
			}

			// Any concurrency less than '4' just stick to '4' concurrent
			// operations for now to begin with.

	return concErr{
		errMap:     errMap,
		summaryErr: c.toErrorFromErrMap(errMap, actionName),
	}
}

// concDo calls actions concurrently. selfActionFn is run for the current
// cluster and peerActionFn is run for each peer replication cluster.

- In the API Priority and Fairness feature, priority levels that are exempt from limitation can now be given a nominal and a lendable concurrency and their dispatching borrows from the concurrency limits of the other priority levels.  For details see https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1040-priority-and-fairness#dispatching . ([#118782](https://github.com/kubernetes/kube...

     * Stored as a long value representing milliseconds since epoch.
     * Used for audit trail and concurrency control.
     */
    @ValidateTypeFailure
    public Long updatedTime;

    /**
     * The version number of the elevate word configuration for optimistic locking.
     * This field is required to prevent concurrent modification conflicts
     * by ensuring the configuration hasn't been modified by another process.
     */