API Gateway Container Cluster Configuration

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You can combine webMethods API Gateway Docker containers to form a cluster.

To configure an webMethods API Gateway Docker container cluster:

  1. Configure loadbalancer on the Docker host.

    The custom loadbalancer is installed on the Docker host. For more details on setting up the load balancer, see webMethods API Gateway Cluster Configuration.

  2. Configure Terracotta Server Array.
    Note: This configuration step is required only if your webMethods API Gateway cluster uses TSA.

    webMethods API Gateway requires a Terracotta Server Array installation. For details, see IBM webMethods Integration Server Clustering Guide and Terracotta documentation (https://www.terracotta.org/). The Terracotta Server Array on its own can be deployed as a Docker container.

  3. Create the basic webMethods API Gateway Docker image.

    For details on creating the webMethods API Gateway Docker image, see Building the Docker Image for an API Gateway Instance.

  4. Create cluster webMethods API Gateway Docker image and enhance it with the cluster configuration in one of the following ways:
    • Clustered all-in-one containers that consist of webMethods API Gateway, API Data Store (Elasticsearch), and Kibana.
    • Clustered webMethods API Gateway containers with externalized Elasticsearch and Kibana containers.

Clustered all-in-one containers that consist of webMethods API Gateway, Kibana and API Data Store

Although webMethods API Gateway clusters with externalized Elasticsearch is the preferred approach, you can also cluster webMethods API Gateway all-in-one containers. The clustering can be configured using Apache Ignite or Terracotta Server Array.

Note: Having external Kibana is an optional variation.

Peer-to-peer clustering using Apache Ignite

The following diagram depicts peer-to-peer clustering using Apache Ignite.

The all-in-one containers hold webMethods API Gateway, Kibana, and Elasticsearch. The clustering is done using Apache Ignite and the cluster capabilities of the embedded Elasticsearch instances.

Inject the required settings for the cluster configuration during Docker run through an environment file.

A sample environment file when clustering is done through Apache Ignite looks as follows. 

apigw_cluster_aware=true
apigw_cluster_name=APIGatewayCluster
apigw_cluster_ignite_hostnames=apigw1,apigw2,apigw3
apigw_cluster_ignite_discoveryPort=10100
apigw_cluster_ignite_communicationPort=10400

Clustering using Terracotta Server Array

The following diagram depicts clustering using TSA.

The all-in-one containers hold webMethods API Gateway, Kibana, and Elasticsearch. The clustering is done using a TSA and the cluster capabilities of the embedded Elasticsearch instances.

Inject the required settings for the cluster configuration during Docker run through an environment file.

A sample environment file when clustering is done through Terracotta server array looks as follows. 

apigw_cluster_tsaUrls=tc:9510
apigw_terracotta_license_filename=terracotta-license.key
apigw_cluster_discoverySeedHosts=apigw1:9340,apigw2:9340,apigw3:9340
apigw_cluster_initialMasterNodes=apigw1_master

Clustered webMethods API Gateway containers with externalized Elasticsearch and Kibana containers

The API Gateway cluster can be peer-to-peer, or based on TSA, and it communicates to a cluster of Elasticsearch containers through a load balancer. The Elasticsearch load balancer also provides the Elasticsearch endpoint for the Kibana containers.
Note: The externalized Kibana is optional. You can still run Kibana within the webMethods API Gateway container.

Peer-to-peer clustering using Apache Ignite

To cluster webMethods API Gateway with external containers for Elasticsearch, Kibana, and Apache Ignite, you can inject the settings into an webMethods API Gateway Docker image when starting, by providing an environment file. The environment file has to define the following environment variables. 

apigw_cluster_aware=true
apigw_cluster_name=name
apigw_cluster_ignite_hostnames=comma-separated list of host names
apigw_cluster_ignite_discoveryPort=port
apigw_cluster_ignite_communicationPort=port
apigw_elasticsearch_hosts=host:port
apigw_elasticsearch_http_username=user
apigw_elasticsearch_http_password=password
apigw_kibana_dashboardInstance=instance

A sample assignment of environment variables looks as follows: 

apigw_cluster_aware=true
apigw_cluster_name=APIGatewayCluster
apigw_cluster_ignite_hostnames=apigw1,apigw2,apigw3
apigw_cluster_ignite_discoveryPort=10100
apigw_cluster_ignite_communicationPort=10400
apigw_elasticsearch_hosts=testhost1:9200
apigw_elasticsearch_http_username=
apigw_elasticsearch_http_password=
apigw_kibana_dashboardInstance=http://testhost1:9405

Clustering using Terracotta Server Array

To cluster the webMethods API Gateway with external containers for Elasticsearch, Kibana, and TSA, you can inject the settings into an webMethods API Gateway Docker image when starting by providing an environment file. The environment file has to define the following environment variables. 

apigw_cluster_tsaUrls=host:port
apigw_terracotta_license_filename=license-key-filename
 
apigw_elasticsearch_hosts=host:port
apigw_elasticsearch_http_username=user
apigw_elasticsearch_http_password=password
 
apigw_kibana_dashboardInstance=instance

A sample assignment of the environment variables looks as follows. 

apigw_cluster_tsaUrls=tc:9510
apigw_terracotta_license_filename=terracotta-license.key
 
apigw_elasticsearch_hosts=testhost1:9200
apigw_elasticsearch_http_username=
apigw_elasticsearch_http_password=
 
apigw_kibana_dashboardInstance=http://testhost1:9405