Installing stand-alone Event Gateways

A stand-alone gateway is useful when you need to position the gateway closer to your Kafka installation. If you need to install the Event Gateway on a different cluster to your Event Manager instance, you can install a stand-alone Event Gateway instance. The following sections describe how to install a stand-alone Event Gateway instance in an online environment.

Note: Stand-alone Event Gateway instances can only be installed in an online environment.

Limitations

Endpoints that need to be shared between a mixture of stand-alone gateways and those in a Kubernetes cluster must use a host address that is resolvable by all gateways. For example, if the cluster that is associated with a Kafka topic uses an internal service address for a Kafka cluster, then a stand-alone gateway will not be able to resolve that address outside of the cluster. In such cases, separate event source aliases must be created and deployed to different gateways.

A Kafka client implementation might require that the Event Gateway presents at least one endpoint for each broker that the client is expecting to connect to. Therefore, ensure you manually configure the number of ports exposed on the host of the Event Gateway container to be greater than or equal to the maximum number of brokers across all the clusters that the Event Gateway is managing. Also ensure that all the host ports map to the exposed port on the Event Gateway container.

Prerequisites

The stand-alone Event Gateway is provided as a Docker image and can be used only where a single Docker engine is deployed on the host. Entitlement and usage are tracked by different licensing tools depending on your deployment. If you have a usage-based license for tracking the number of API calls, ensure that you configure the gateway for the IBM License Service. Otherwise, use the IBM License Metric Tool for any other deployments.

Event Endpoint Management 11.2.1 icon In Event Manager 11.2.1 and later, the client certificate for the Event Gateway does not require a subject alternative name (SAN) URI to be specified. Instead, this information is set by using the configuration options when deploying the Event Gateway. For information about installing a stand-alone gateway by using the previous deployment process, see the 11.1 documentation.

System requirements

Ensure that you have at least 2 CPU cores and 2 GiB of memory available on the system that you want to install and run the stand-alone Event Gateway.

Supported operating systems

  • Red Hat Enterprise Linux® Server 7 (x86-64)
  • SUSE Linux® Enterprise Server (SLES) 12.0 (x86-64)
  • Linux on IBM z13 (s390x) or later systems

Certificates

The Event Gateway uses a number of certificates to ensure that communication is encrypted. You need both the certificate and the associated private key when you run the service. The requirements are as follows:

  • A certificate for the Event Gateway to present to Kafka applications that are connecting to the gateway.
  • A client certificate for the Event Gateway to present to the Event Manager, which is used to register, authenticate, and authorize this gateway instance.
  • The certificate for the CA that issues the Event Manager certificate that the gateway connects to for its configuration.

Create a local folder called certs on the host where you want to run the service and add the following files (all files are in PEM format):

  • client.pem: The public certificate for Event Gateway to present to Kafka clients.
  • client.key: The private key for the Event Gateway client certificate.
  • egwclient.pem: The public certificate for Event Gateway to use a client certificate when it connects to the associated Event Manager.
  • egwclient-key.pem: The private key for Event Gateway to use a client certificate.
  • ca.pem: The public certificate for the CA that issues the Event Manager certificate.

Event Gateway client certificate

The Event Gateway uses a client certificate to register itself with the Event Manager. This certificate provides the authentication and authorization that allows the gateway to pull information about topics and subscriptions from the Event Manager. This means that the certificate must be issued by a CA that the Event Manager trusts.

Installing

To install a stand-alone Event Gateway, download the Event Gateway Docker image from the IBM Container software library as follows:

docker login cp.icr.io -u cp
docker pull cp.icr.io/cp/ibm-eventendpointmanagement/egw:11.2.2

The password to log in to the IBM Container software library is your entitlement key, which you can obtain from the container software library site.

Configuration options

Before you start the Event Gateway, define the following options:

  • EEM_BACKEND_URL: The URL to be used by the Event Gateway to connect to the Event Manager. This URL is the gateway API endpoint defined in the Event Manager, and will contain ibm-eem-gateway in the URL.
  • GATEWAY_ID: The unique ID for this gateway.
  • GATEWAY_GROUP: The name of the group for the gateway to join.
  • GATEWAY_PORT: The port on the host that is exposed for external connections from Kafka applications.
  • GATEWAY_CONTACT: Optional: for providing contact information that is displayed in the Event Endpoint Management UI.
  • PATH_TO_CERTIFICATES: A local directory in which the certificates are placed.
  • KAFKA_ADVERTISED_LISTENER: The host and port that Kafka applications should receive when making requests. If applications have direct access, then this will be the host and port of the Event Gateway, otherwise it should be the host and port of the routing or proxy service that is in front of the Event Gateway.
  • PORT_MAPPINGS: a sequence of port assignments (-p <HOST_PORT>:<GATEWAY_PORT>) that satisfies the requirement that the number of exposed host ports is greater than, or equal to, the total number of Kafka brokers that are managed by this gateway.
  • swid: Specifies the license under which the stand-alone Event Gateway is deployed. It must be either EA for Event Automation license, or CP4I for Cloud Pak for Integration license.
  • ubp: Optionally, set this environment variable in the Docker container if the stand-alone Event Gateway is licensed under Usage Based Pricing terms. You cannot specify both the ubp and swid options at the same time as they are mutually exclusive licensing terms.

Starting the Event Gateway

To run the Event Gateway, use the following command and the configuration options that are described in the previous section:

docker run -e backendURL="<EEM_BACKEND_URL>" -e swid="EA/CP4I" [-e ubp=true] \
   -e KAFKA_ADVERTISED_LISTENER="<KAFKA_ADVERTISED_LISTENER>" -e GATEWAY_PORT="<GATEWAY_PORT>" \
   -e GATEWAY_ID="<GATEWAY_ID>"  -e GATEWAY_GROUP="<GATEWAY_GROUP>" -e GATEWAY_CONTACT="<GATEWAY_CONTACT>" \
   -e certPaths="/certs/eem/client.pem,/certs/eem/client.key,/certs/eem/ca.pem,/certs/eem/egwclient.pem,/certs/eem/egwclient-key.pem" \
   -v <PATH_TO_CERTIFICATES>:/certs/eem -d -p <HOST_PORT>:<GATEWAY_PORT> <IMAGE_NAME_FROM_CONTAINER_REGISTRY>

When the Event Gateway starts, it connects to the specified Event Manager at which point it is registered.

Installing the IBM License Metric Tool

Important: This licensing tool is required for all Event Endpoint Management deployments except usage-based ones.

The IBM License Metric Tool checks usage and entitlement to the stand-alone Event Gateway.

Ensure that you install the IBM License Metric Tool before you install the stand-alone Event Gateway. Also review the additional Docker-specific License Metric Tool considerations.

Note: When deploying a stand-alone gateway on Linux on IBM z13 (s390x), the IBM License Metric Tool disconnected scanner must be installed and configured alongside the stand-alone gateway. This is in addition to the License Metric Tool running on a supported platform. Submit the results from the disconnected scanner to the License Metric Tool at regular intervals to maintain licensing compliance.