docs/datacenter/ucp/2.1/guides/admin/configure/use-domain-names-to-access-...

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Configure the HTTP Routing Mesh Learn how to configure UCP's HTTP Routing Mesh ucp, services, http, dns

UCP provides an HTTP routing mesh, that extends the networking capabilities of Docker Engine. Docker Engine provides load balancing and service discovery at the transport layer for TCP and UDP connections. UCP's HTTP routing mesh allows you to extend service discovery to have name-based virtual hosting for HTTP and HTTPS services.

See the Docker Engine documentation on overlay networks for more information on what Docker Engine provides.

Enable the HTTP routing mesh

To enable the HTTP routing mesh, go to the UCP web UI, navigate to the Settings page, and click the Routing Mesh tab.

The default port for HTTP services is 80, and the default port for HTTPS services is 8443. You may choose an alternate port on this screen.

Check the checkbox to enable the HTTP routing mesh. This will create a service called ucp-hrm and a network called ucp-hrm.

If the HTTP routing mesh receives a HTTP request for a domain that it does not handle, it returns a 503 error (Bad Gateway). For HTTPS requests, all unknown domains are routed to the UCP web interface.

HTTPS support

The HTTP routing mesh has support for routing using HTTPS. Using a feature of HTTPS called Server Name Indication, the HTTP routing mesh is able to route connections to service backends without terminating the HTTPS connection.

To use HTTPS support, no certificates for the service are provided to the HTTP routing mesh. Instead, the backend service must handle HTTPS connections directly. Services that meet this criteria can use the SNI protocol to indicate handling of HTTPS in this manner.

Route to a service

The HTTP routing mesh can route to a Docker service that runs a webserver. This service must meet three criteria:

  • The service must be connected a network with a com.docker.ucp.mesh.http label
  • The service must publish one or more ports
  • The service must have one or more labels prefixed with com.docker.ucp.mesh.http to specify the ports to route (see the syntax below)

These options can be configured using the UCP UI, or can be entered manually using the docker service command.

Route domains to the HTTP routing mesh

The HTTP routing mesh uses the Host HTTP header (or the Server Name Indication field for HTTPS requests) to determine which service should receive a particular HTTP request. This is typically done using DNS and pointing one or more domains to one or more nodes in the UCP cluster.

Networks, Access Control, and the HTTP routing mesh

The HTTP routing mesh uses one or more overlay networks to communicate with the backend services. By default, a single network is created called ucp-hrm, with the access control label ucp-hrm. Adding a service to this network either requires administrator-level access, or the user must be in a group that gives them ucp-hrm access.

This default configuration does not provide any isolation between services using the HTTP routing mesh.

Isolation between services may be implemented by creating one or more overlay networks with the label com.docker.ucp.mesh.http prior to enabling the HTTP routing mesh. Once the HTTP routing mesh is enabled, it will be able to route to all services attached to any of these networks, but services on different networks cannot communicate directly.

Using the HTTP routing mesh

Once DNS and networks are configured, you can begin setting up services for these domains. See the guides for the UCP web UI and Docker CLI.

Disable the HTTP routing mesh

To disable the HTTP routing mesh, first ensure that all services that are using the HTTP routing mesh are disconnected from the ucp-hrm network.

Next, go to the UCP web UI, navigate to the Settings page, and click the Routing Mesh tab. Uncheck the checkbox to disable the HTTP routing mesh.

Troubleshoot

If a service is not configured properly for use of the HTTP routing mesh, this information is available in the UI when inspecting the service.

More logging from the HTTP routing mesh is available in the logs of the ucp-controller containers on your UCP manager nodes.