Data plane proxy
A data plane proxy (DPP) is the part of Kuma that runs next to each workload that is a member of the mesh. A DPP is composed of the following components:
- a
Dataplane
entity defines the configuration of the DPP - a
kuma-dp
binary runs on each instance that is part of the mesh. This binary spawns the following subprocesses:Envoy
receives configuration from the control-plane to manage traffic correctlycore-dns
resolves Kuma specific DNS entries
Data plane proxies are also called sidecars.
We have one instance of kuma-dp
for every instance of every service.
Concepts
Inbound
An inbound consists of:
- a set of tags
- the port the workload listens on
Most of the time a DPP exposes a single inbound. When a workload exposes multiple ports, multiple inbounds can be defined.
Tags
Tags are a set of key-value pairs (.e.g version=v2
) that are defined for each DPP inbound. These tags serve the following purposes:
- specifying the service this DPP inbound is part of
- adding metadata about the exposed service
- allowing subsets of DPPs to be selected by these tags
Tags prefixed with kuma.io
are reserved:
kuma.io/service
identifies the service name. On Kubernetes this tag is automatically created, while on Universal it must be specified manually. This tag must always be present.kuma.io/zone
identifies the zone name in a multi-zone deployment . This tag is automatically created and cannot be overwritten.kuma.io/protocol
identifies the protocol of the service exposed by this inbound. Accepted values aretcp
,http
,http2
,grpc
andkafka
.
Service
A service is a group of all DPP inbounds that have the same kuma.io/service
tag.
Outbounds
An outbound allows the workload to consume a service in the mesh using a local port. This is only useful when not using (/docs/2.9.x/production/dp-config/transparent-proxying/) .
Dataplane
entity
The Dataplane
entity consists of:
- the IP address used by other DPPs to connect to this DPP
- inbounds
- outbounds
A Dataplane
entity must be present for each DPP. Dataplane
entities are managed differently depending on the environment:
- Kubernetes: The control plane
automatically generates
the
Dataplane
entity. - Universal: The
user defines
the
Dataplane
entity.
Dynamic configuration of the data plane proxy
When the DPP runs:
- The
kuma-dp
retrieves Envoy startup configuration from the control plane. - The
kuma-dp
process starts Envoy with this configuration. - Envoy connects to the control plane using XDS and receives configuration updates when the state of the mesh changes.
The control plane uses policies and Dataplane
entities to generate the DPP configuration.
Data plane proxy ports
When we start a data-plane via kuma-dp
we expect all the inbound and outbound service traffic to go through it. The inbound and outbound ports are defined in the dataplane specification when running in universal mode, while on Kubernetes the service-to-service traffic always runs on port 15001
.
In addition to the service traffic ports, the data-plane automatically also opens the envoy
administration interface listener on the 127.0.0.1:9901
.