78 lines
4 KiB
Markdown
78 lines
4 KiB
Markdown
---
|
|
layout: "intro"
|
|
page_title: "Consul vs. Istio"
|
|
sidebar_current: "vs-other-istio"
|
|
description: |-
|
|
Istio is a platform for connecting and securing microservices. This page describes the similarities and differences between Istio and Consul.
|
|
---
|
|
|
|
# Consul vs. Istio
|
|
|
|
Istio is an open platform to connect, manage, and secure microservices.
|
|
|
|
To enable the full functionality of Istio, multiple services must
|
|
be deployed. For the control plane: Pilot, Mixer, and Citadel must be
|
|
deployed and for the data plane an Envoy sidecar is deployed. Additionally,
|
|
Istio requires a 3rd party service catalog from Kubernetes, Consul, Eureka,
|
|
or others. At a minimum, three Istio-dedicated services along with at
|
|
least one separate distributed system (in addition to Istio) must be
|
|
configured for the full functionality of Istio.
|
|
|
|
Istio plans to work on any platform, but currently has a hard dependency
|
|
on the Kubernetes API. While the documentation covers connecting non-Kubernetes
|
|
services, it assumes that a Kubernetes deployment exists for the control
|
|
plane.
|
|
|
|
Istio provides layer 7 features for path-based routing, traffic shaping,
|
|
load balancing, and telemetry. Access control policies can be configured
|
|
targeting both layer 7 and layer 4 properties to control access, routing,
|
|
and more based on service identity.
|
|
|
|
Consul is a single binary providing both server and client capabilities, and
|
|
includes all functionality for service catalog, configuration, TLS certificates,
|
|
authorization, and more. No additional systems need to be installed to use
|
|
Consul, although Consul optionally supports external systems such as Vault
|
|
to augment behavior. This architecture enables Consul to be easily installed
|
|
on any platform, including directly onto the machine.
|
|
|
|
Consul uses an agent-based model where each node in the cluster runs a
|
|
Consul Client. This client maintains a local cache that is efficiently updated
|
|
from servers. As a result, all secure service communication APIs respond in
|
|
microseconds and do not require any external communication. This allows us to
|
|
do connection enforcement at the edge without communicating to central
|
|
servers. Istio flows requests to a central Mixer service and must push
|
|
updates out via Pilot. This dramatically reduces the scalability of Istio,
|
|
whereas Consul is able to efficiently distribute updates and perform all
|
|
work on the edge.
|
|
|
|
The data plane for Consul is pluggable. It includes a built-in proxy with
|
|
a larger performance trade off for ease of use. But you may also use third
|
|
party proxies such as Envoy. The ability to use the right proxy for the job
|
|
allows flexible heterogeneous deployments where different proxies may be
|
|
more correct for the applications they're proxying.
|
|
|
|
In addition to third party proxy support, applications can natively integrate
|
|
with the Connect protocol. As a result, the performance overhead of introducing
|
|
Connect is negligible. These "Connect-native" applications can interact with
|
|
any other Connect-capable services, whether they're using a proxy or are
|
|
also Connect-native.
|
|
|
|
Consul enforces authorization and identity to layer 4 only -- either the TLS
|
|
connection can be established or it can't. We believe
|
|
service identity should be tied to layer 4, whereas layer 7 should be used
|
|
for routing, telemetry, etc. We encourge users to use the pluggable data
|
|
plane layer to use a proxy that supports the layer 7 features necessary
|
|
for the cluster. Consul will be adding more layer 7 features in the future.
|
|
|
|
Consul implements automatic TLS certificate management complete with rotation
|
|
support. Both leaf and root certificates can be rotated automatically across
|
|
a large Consul cluster with zero disruption to connections. The certificate
|
|
management system is pluggable through code change in Consul and will be
|
|
exposed as an external plugin system shortly. This enables Consul to work
|
|
with any PKI solution.
|
|
|
|
Because Consul's service connection feature "Connect" is built-in, it
|
|
inherits the operational stability of Consul. Consul has been in production
|
|
for large companies since 2014 and is known to be deployed on as many as
|
|
50,000 nodes in a single cluster.
|