Networking

Ingress traffic

Ingress to Service

The vCluster has the option to enable Ingress resources synchronization. That means that you can create an ingress in a vCluster to make a service in this vCluster available via a hostname/domain. However, instead of having to run a separate ingress controller in each vCluster, the ingress resource will be synchronized to the underlying cluster (when enabled) which means that the vCluster can use a shared ingress controller that is running in the host cluster. This helps to share resources across different vClusters and is easier for users of vClusters because otherwise, they would need to install an ingress controller and manually configure DNS for each vCluster.

From inside a virtual cluster

Pod in the virtual cluster to Pod in the same virtual cluster

Pods run inside the underlying host cluster. vCluster's syncer component syncs Pods between host and virtual cluster. These synced Pods have cluster-internal IP addresses and can communicate with each other via IP-based networking.

No additional configuration is required for Pod to Pod networking in the same virtual cluster.

Pod in the virtual cluster to Service in the same virtual cluster

To allow pods to communicate with services, vCluster also synchronizes Service objects, while stripping away unnecessary information from the resource. However, instead of using the DNS names of the Services inside the host cluster, vCluster has its own DNS service which allows virtual cluster pods to use much more intuitive DNS mappings, just as in a regular cluster.

No additional configuration is required for Pod to Service networking in the same virtual cluster.

Pod in the virtual cluster to Service in the host cluster

See Host cluster to virtual cluster.

Pod in the virtual cluster to Service in a different virtual cluster

See Mapping services across vCluster instances.

From the host cluster

Pod in the host cluster to Service in the virtual cluster

See Virtual cluster to host cluster

Config reference

networking required object

Networking options related to the virtual cluster.

replicateServices required object

ReplicateServices allows replicating services from the host within the virtual cluster or the other way around.

toHost required object[]

ToHost defines the services that should get synced from virtual cluster to the host cluster. If services are synced to a different namespace than the virtual cluster is in, additional permissions for the other namespace are required.

from required string

From is the service that should get synced. Can be either in the form name or namespace/name.

to required string

To is the target service that it should get synced to. Can be either in the form name or namespace/name.

fromHost required object[]

FromHost defines the services that should get synced from the host to the virtual cluster.

from required string

From is the service that should get synced. Can be either in the form name or namespace/name.

to required string

To is the target service that it should get synced to. Can be either in the form name or namespace/name.

resolveDNS required object[]

ResolveDNS allows to define extra DNS rules. This only works if embedded coredns is configured.

hostname required string

Hostname is the hostname within the vCluster that should be resolved from.

service required string

Service is the virtual cluster service that should be resolved from.

namespace required string

Namespace is the virtual cluster namespace that should be resolved from.

target required object

Target is the DNS target that should get mapped to

hostname required string

Hostname to use as a DNS target

ip required string

IP to use as a DNS target

hostService required string

HostService to target, format is hostNamespace/hostService

hostNamespace required string

HostNamespace to target

vClusterService required string

VClusterService format is hostNamespace/vClusterName/vClusterNamespace/vClusterService

advanced required object

Advanced holds advanced network options.

clusterDomain required string cluster.local

ClusterDomain is the Kubernetes cluster domain to use within the virtual cluster.

fallbackHostCluster required boolean false

FallbackHostCluster allows to fallback dns to the host cluster. This is useful if you want to reach host services without any other modification. You will need to provide a namespace for the service, e.g. my-other-service.my-other-namespace

proxyKubelets required object

ProxyKubelets allows rewriting certain metrics and stats from the Kubelet to "fake" this for applications such as prometheus or other node exporters.

byHostname required boolean true

ByHostname will add a special vCluster hostname to the nodes where the node can be reached at. This doesn't work for all applications, e.g. Prometheus requires a node IP.

byIP required boolean true

ByIP will create a separate service in the host cluster for every node that will point to virtual cluster and will be used to route traffic.