which can use IPv4, IPv6, or both, and you can change this setting for existing Services. Details are available in updated [IPv4/IPv6 dual-stack docs](https://docs.k8s.io/concepts/services-networking/dual-stack/), which cover the nuanced array of options.

We expect this implementation to progress from alpha to beta and GA in coming releases, so we’re eager to have you comment about your dual-stack experiences in [#k8s-dual-stack](https://kubernetes.slack.com/messages/k8s-dual-stack) or...

    List<Optional<Object>> optionals = ImmutableList.of(Optional.absent(), Optional.absent());
    assertThat(Optional.presentInstances(optionals)).isEmpty();
  }

  public void testPresentInstances_somePresent() {
    List<Optional<String>> optionals =
        ImmutableList.of(Optional.of("a"), Optional.<String>absent(), Optional.of("c"));

    * `kubectl create configmap` has a new option `--from-env-file` that populates a configmap from file which follows a key=val format for each line. ([#38882](https://github.com/kubernetes/kubernetes/pull/38882), [@fraenkel](https://github.com/fraenkel))

    * `kubectl create secret` has a new option `--from-env-file` that populates a secret from file which follows a key=val format for each line.

- Added a `--topology-manager-policy-options` flag to the kubelet to support fine tuning the topology manager policies. The first policy option, `prefer-closest-numa-nodes`, allows these policies to favor sets of NUMA nodes with shorter distance between nodes when making admission decisions. ([#112914](https://github.com/kubernetes/kubernetes/pull/112914),...

* kubeadm now has a join timeout that can be controlled via the `discoveryTimeout` config option. This option is set to 5 minutes by default. ([#60983](https://github.com/kubernetes/kubernetes/pull/60983), [@rosti](https://github.com/rosti))

public final Option$WithFilter withFilter(Function1); public final boolean forall(Function1); public final Option orElse(Function0); public final collection.immutable.List toList(); public void Option(); } scala/Option$WithFilter.class package scala; public final synchronized class Option$WithFilter { public final Function1 scala$Option$WithFilter$$p; public final Option map(Function1); public void Option$WithFilter(Option, Function1); } scala/Option$.class package scala; public final synchronized...

  // If this option is set, the ports that will be used must be specified.
  // Default to false.
  // +k8s:conversion-gen=false
  // +optional
  optional bool hostNetwork = 11;

  // Use the host's pid namespace.
  // Optional: Default to false.
  // +k8s:conversion-gen=false
  // +optional
  optional bool hostPID = 12;

  // Use the host's ipc namespace.
  // Optional: Default to false.

        }

        @Override
        public String id() {
            return "UNRESOLVED";
        }

        @Override
        public Optional<String> option() {
            return Optional.empty();
        }

        @Override
        public String[] option(Iterable<? extends Path> paths) {
            return new String[0];
        }
    };

    /**

  optional ImageReviewSpec spec = 2;

  // Status is filled in by the backend and indicates whether the pod should be allowed.
  // +optional
  optional ImageReviewStatus status = 3;
}

// ImageReviewContainerSpec is a description of a container within the pod creation request.
message ImageReviewContainerSpec {
  // This can be in the form image:tag or image@SHA:012345679abcdef.
  // +optional

  // Standard object's metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;

  // Status is filled in by the server with the user attributes.
  optional SelfSubjectReviewStatus status = 2;
}

// SelfSubjectReviewStatus is filled by the kube-apiserver and sent back to a user.