Configure and Deploy Confluent Private Cloud Gateway using Docker

Configure and deploy Confluent Private Cloud Gateway (Confluent Gateway) using Docker. You can use this deployment path to run Confluent Gateway on-premises, in private cloud VPCs, and across hybrid environments.

For general requirements and considerations, see Requirements and considerations. For Docker-specific requirements, see Docker software requirements.

The high-level steps to deploy Confluent Gateway using Docker are:

Configure Confluent Gateway by defining streaming domains, routes, and administration settings in a Docker Compose file.
Deploy Confluent Gateway by pulling the Confluent Gateway Docker image and starting the service with Docker Compose.

After deployment, configure security and reconfigure clients to use the Confluent Gateway endpoint. For more information, see Next steps.

Configure Confluent Gateway using Docker Compose

Provide the configuration settings in a Docker Compose YAML file. This guide uses docker-compose.yaml as an example.

The top-level layout for the Confluent Gateway configuration file is as follows:

gateway:
  image:                  --- [1]
  name:                   --- [2]
  streamingDomains: []    --- [3]
  secretStores: []        --- [4]
  routes: []              --- [5]
  admin: {}               --- [6]

[1] The Confluent Gateway Docker image in the pattern: confluentinc/cpc-gateway:<version_tag>. <version_tag> is the Confluent Gateway version.
[2] The Confluent Gateway instance identifier.
[3] A list of streaming domains that represent Apache Kafka® clusters. For more information, see Streaming domains configuration.
[4] A list of secret stores. Required for authentication swapping. See Secret store configuration for details.
[5] A list of client routing rules. For more information, see Routes configuration.
[6] Admin and metrics configuration. For more information, see Administration and metrics configuration.

Streaming domains configuration

Streaming domains are logical representations of your Kafka clusters in Confluent Gateway.

gateway:
  streamingDomains:
    - name:               --- [1]
      type:               --- [2]
      kafkaCluster:       --- [3]
        name:             --- [4]
        bootstrapServers: --- [5]
          - id:           --- [6]
            endpoint:     --- [7]
            ssl:          --- [8]
        nodeIdRanges:     --- [9]
          - name:         --- [10]
            start:        --- [11]
            end:          --- [12]

[1] A unique name for the streaming domain.
[2] The type of the streaming domain. Set to kafka by default.
[3] A Kafka cluster, including Confluent Server, Confluent Private Cloud Kafka, or Apache Kafka®, that the Confluent Gateway can route traffic to.
[4] The name of the Kafka cluster.
[5] A list of Kafka bootstrap servers in the format host:port. At minimum, one bootstrap server is required per Kafka cluster. For each listener, you can define one bootstrap server.
[6] A unique identifier for the bootstrap server. Use the protocol name (such as SASL_PLAINTEXT, SSL, or PLAINTEXT_SASL_PLAIN) for clear distinction between the TLS channel type and SASL mechanism.
[7] The bootstrap endpoint of the Kafka broker in the format: host:port.
[8] Only required for SSL/SASL_SSL configuration. Supported certificate types are JKS, PKCS12, and PEM.
See the SSL configuration section for details.
[9] The node ID ranges. Only required for port-based broker identification. These should be the broker IDs defined in the Kafka deployment.
[10] The name of the node ID range.
[11] The start of the node ID range, inclusive.
[12] The end of the node ID range, inclusive.

An example configuration for a Confluent Gateway streaming domain:

streamingDomains:
  - name: sales # unique across gateway
    type: kafka # default: kafka
    kafkaCluster:
      name: sales-cluster # default: <streamingDomain.name>
      bootstrapServers:
        - id: PLAINTEXT-1
          endpoint: kafka0.example.com:9092
        - id: SASL_SSL-1
          endpoint: kafka0.example.com:9093
          ssl:  # required when using SASL_SSL/SSL
            ignoreTrust: false
            truststore:
              type: PKCS12  # default: JKS
              location: /opt/ssl/client-truststore.p12
              password:
                file: /opt/secrets/client-truststore.password
            keystore: # gateway's identity when needed
              type: PKCS12 # default: JKS
              location: /opt/ssl/gw-keystore.p12
              password:
                file: /opt/secrets/gw-keystore.password
              keyPassword:
                value: inline-password
      nodeIdRanges:
        - name: default
          start: 0              # inclusive
          end: 3                # inclusive

password can be a file path or an inline value. For details, see Password configuration.
ignoreTrust skips certificate validation. Not recommended for production. When true, Confluent Gateway ignores all other SSL settings.

Routes configuration

Routes are Confluent Gateway endpoints where client applications connect to stream data.

Confluent Gateway uses routes to define how client applications connect to Kafka clusters. Clients connect to Confluent Gateway as if it were a Kafka cluster, while Confluent Gateway handles routing and governance.

gateway:
  routes:
    - name:                         --- [1]
      endpoint:                     --- [2]
      brokerIdentificationStrategy: --- [3]
        type:                       --- [4]
        pattern:                    --- [5]
      streamingDomain:              --- [6]
        name:                       --- [7]
        bootstrapServerId:          --- [8]
      security:                     --- [9]
      fence:                        --- [10]

[1] The unique name for the route.
[2] The host:port combination that Confluent Gateway listens on. This is the external address clients use to bootstrap to the Kafka cluster.
[3] Specifies the strategy for mapping client requests to a specific Kafka broker.
[4] The type of broker identification strategy. Set to port (default) or host.
- port strategy: Each Kafka broker is identified using a unique port number. This is the default strategy.
  Clients connect to different ports to reach specific brokers (for example, port 9092 to connect with broker-0, port 9093 to connect with broker-1).
  The nodeIdRanges from the streaming domain configured in Streaming domains configuration is used. The nodeIdRanges must be present in the streaming domain associated with the route.
- host strategy: Each Kafka broker is represented using a unique hostname.
  Clients use different host names to reach specific brokers (for example, broker-0.kafka.company.com, broker-1.kafka.company.com), and Confluent Gateway routes based on the Server Name Indication (SNI) header.
  The pattern setting ([5]) is used.
[5] The pattern for the broker identification strategy. Required if the type ([4]) is host. For example, broker-$(nodeId).eu-gw.sales.example.com:9092.
[6] The reference to a streaming domain.
[7] The name of the streaming domain. Must be a valid name from the gateway.streamingDomains[].name.
[8] The bootstrap server ID. Must match kafkaCluster.bootstrapServers[].id.
[9] The security configuration. For more information, see Configure Security for Confluent Private Cloud Gateway.
[10] Optional. The fencing filter configuration. See Fencing filter for details.

An example configuration for Confluent Gateway routes:

gateway:
 routes:
   - name: eu-sales
     endpoint: eu-gw.sales.example.com:9092
     brokerIdentificationStrategy:
       type: host
       pattern: broker-$(nodeId).eu-gw.sales.example.com:9092
     streamingDomain:
       name: sales
       bootstrapServerId: SASL_SSL-1

Route filters configuration

Filters allow you to control and manage traffic flow for specific routes in Confluent Gateway. You can apply filters at the route level to enforce policies, block or allow requests, and customize error handling for different scenarios.

Fencing filter

The fencing filter in Confluent Gateway is a route-level filter that allows you to control the traffic flow on a specific route. It supports two fencing scopes:

ALL: Blocks all requests on the specified route. Useful for scenarios such as maintenance windows or when you want to temporarily disable access to a route.
NONE: Allows all requests on the specified route.

gateway:
  routes:
    - name:
      fence:
        scope:          --- [1]
        errorCode:      --- [2]
        errorMessage:   --- [3]

[1] The fencing scope of the filter. The default value is NONE. Set to ALL to block all requests on the route.
[2] Optional. The error code to return for blocked requests. The default value is BROKER_NOT_AVAILABLE.
For a list of valid error codes, see Kafka protocol error codes.
[3] Optional. The error message to return for blocked requests. The default value is This route is currently unavailable - all requests are blocked.

The following is an example configuration for a Confluent Gateway route with the fencing filter enabled:

gateway:
  routes:
    - name: eu-sales
      endpoint: eu-gw.sales.example.com:9092
      fence:
        scope: ALL
        errorCode: BROKER_NOT_AVAILABLE
        errorMessage: "Maintenance in progress - route temporarily unavailable"
      brokerIdentificationStrategy:
        type: host
        pattern: broker-$(nodeId).eu-gw.sales.example.com:9092
      streamingDomain:
        name: sales
        bootstrapServerId: SASL_SSL-1

Administration and metrics configuration

The admin section configures the Confluent Gateway administrative service, including the bind address, TCP port, metrics endpoint, JVM metrics collection, and custom metric tags.

gateway:
  admin:
    bindAddress:             --- [1]
    port:                    --- [2]
    endpoints:
      metrics:               --- [3]
    jvmMetrics:              --- [4]
      - JvmGcMetrics
      - JvmMemoryMetrics
      - JvmThreadMetrics
      - ProcessorMetrics
      - UptimeMetrics
    commonTags:              --- [5]
      host:
      region:

[1] The local address to bind admin service and to listen on for incoming connections. The default value is 0.0.0.0.
This address determines which network interfaces the Confluent Gateway uses to expose its administrative endpoints, such as metrics and liveness checks.
[2] The TCP port for exposing admin endpoints. The default value is 9190.
The Confluent Gateway serves metrics at http://{bindAddress}:{port}/metrics. It exposes a liveness check at http://{bindAddress}:{port}/livez.
[3] The metrics endpoints to be enabled and exposed. The default value is true.
[4] Standard JVM metrics captured using Micrometer classes. By default, JvmGcMetrics, JvmMemoryMetrics, JvmThreadMetrics, ProcessorMetrics, and UptimeMetrics are enabled.
[5] Optional. The common tags to be applied to all the metrics.

An example configuration for Confluent Gateway administration and metrics:

admin:
  bindAddress: 0.0.0.0
  port: 9190
  endpoints:
    metrics: true
  jvmMetrics:
    - JvmGcMetrics
    - JvmMemoryMetrics
    - JvmThreadMetrics
    - ProcessorMetrics
    - UptimeMetrics
  commonTags:
    host: pod-0
    region: us-west-2

Enterprise license configuration (optional)

Enterprise mode enables unlimited routes and requires a valid Confluent Private Cloud Enterprise license key. Trial mode (default, no key required) is limited to a maximum of four routes. For a full comparison of modes, see Deploy Confluent Private Cloud Gateway.

If you’re using Enterprise mode, follow these steps to apply your license key:

Contact Confluent to get one or more valid license keys for production use.
Configure the GATEWAY_LICENSES environment variable using the license key you obtained in the previous step.
- Option A: Set the environment variable before starting the Confluent Gateway.
```
export GATEWAY_LICENSES="your-license-key"
```
  To add multiple license keys, use the following syntax using the dollar sign ($) to escape the newline character (\n).
```
export GATEWAY_LICENSES=$'your-first-license-key\nyour-second-license-key'
```
- Option B: Edit docker-compose.yaml. You can add multiple license keys, one per line.
```
gateway:
  environment:
    GATEWAY_LICENSES: |
      your-first-license-key
      your-second-license-key
```
To verify the license status, check the Confluent Gateway logs for license information after starting the Confluent Gateway.
```
docker logs gateway | grep -i license
```

For example license configurations, see Confluent Gateway examples in GitHub.

After completing your configuration, save the file as docker-compose.yaml.

Deploy Confluent Gateway using Docker

To deploy Confluent Gateway:

Pull the Confluent Gateway Docker image to ensure you have the correct version and avoid using a stale locally cached image. For available version tags, see Confluent Gateway on GitHub.
```
docker pull confluentinc/cpc-gateway:<version_tag>
```
For example, to pull version 1.2.0:
```
docker pull confluentinc/cpc-gateway:1.2.0
```
Start Confluent Gateway using the docker-compose.yaml configuration file you set up in Configure Confluent Gateway using Docker Compose.
```
docker compose -f docker-compose.yaml up -d
```
Verify that Confluent Gateway is running.
```
docker ps
```
Confluent Gateway starts in the background after the docker compose command completes. Confirm the Confluent Gateway container appears in the output.

Next steps

After you deploy Confluent Gateway:

Verify the deployment and resolve any startup or connectivity problems. See Troubleshoot Confluent Gateway Docker Deployments for diagnostic steps and symptom-based resolutions.
Configure security for the Confluent Gateway. Security configuration covers authentication, SSL/TLS, secret stores, and passwords for client-to-Confluent Gateway and Confluent Gateway-to-Kafka cluster connections.
Reconfigure clients to communicate with the Confluent Gateway endpoint by pointing their bootstrap.servers to the route endpoint defined in the Confluent Gateway configuration. For migration scenarios between Kafka clusters, see Migrate between Kafka Clusters using Confluent Private Cloud Gateway.