Service Mesh Configuration Overview

There are many configuration options exposed for Consul service mesh. The only option that must be set is the connect.enabled option on Consul servers to enable Consul service mesh. All other configurations are optional and have reasonable defaults.

Consul Connect is the component shipped with Consul that enables service mesh functionality. The terms Consul Connect and Consul service mesh are used interchangeably throughout this documentation.

Agent Configuration

Begin by enabling Connect for your Consul cluster. By default, Connect is disabled. Enabling Connect requires changing the configuration of only your Consul servers (not client agents). To enable Connect, add the following to a new or existing server configuration file. In an existing cluster, this configuration change requires a Consul server restart, which you can perform one server at a time to maintain availability. In HCL:

connect {
  enabled = true
}

"connect": {
 "enabled": true
}

This will enable Connect and configure your Consul cluster to use the built-in certificate authority for creating and managing certificates. You may also configure Consul to use an external certificate management system, such as Vault.

Services and proxies may always register with Connect settings, but they will fail to retrieve or verify any TLS certificates. This causes all Connect-based connection attempts to fail until Connect is enabled on the server agents.

Other optional Connect configurations that you can set in the server configuration file include:

• certificate authority settings
• token replication
• dev mode
• server host name verification

If you would like to use Envoy as your Connect proxy you will need to enable gRPC.

Additionally if you plan on using the observability features of Connect, it can be convenient to configure your proxies and services using configuration entries which you can interact with using the CLI or API, or by creating configuration entry files. You will want to enable centralized service configuration on clients, which allows each service's proxy configuration to be managed centrally via API.

Centralized Proxy and Service Configuration

To account for common Connect use cases where you have many instances of the same service, and many colocated sidecar proxies, Consul allows you to customize the settings for all of your proxies or all the instances of a given service at once using Configuration Entries.

You can override centralized configurations for individual proxy instances in their sidecar service definitions, and the default protocols for service instances in their service registrations.

Schedulers

Consul Connect is especially useful if you are using an orchestrator like Nomad or Kubernetes, because these orchestrators can deploy thousands of service instances which frequently move hosts. Sidecars for each service can be configured through these schedulers, and in some cases they can automate Consul configuration, sidecar deployment, and service registration.

Nomad

Connect can be used with Nomad to provide secure service-to-service communication between Nomad jobs and task groups. The ability to use the dynamic port feature of Nomad makes Connect particularly easy to use. Learn about how to configure Connect on Nomad by reading the integration documentation.

Kubernetes

The Consul Helm chart can automate much of Consul Connect's configuration, and makes it easy to automatically inject Envoy sidecars into new pods when they are deployed. Learn about the Helm chart in general, or if you are already familiar with it, check out its connect specific configurations.