// Metadata created by nebel
//
// ParentAssemblies: assemblies/tutorial/as_starting-services.adoc
// UserStory:

[id="starting-kafka-connect"]
= Starting Kafka Connect

After starting MySQL and connecting to the `inventory` database with the MySQL command line client,
you start the Kafka Connect service.
This service exposes a REST API to manage the {prodname} MySQL connector.

.Procedure

. Open a new terminal, and use it to start the Kafka Connect service in a container.
+
--
This command runs a new container using the {debezium-docker-label} version of the `quay.io/debezium/connect` image:

[source,shell,options="nowrap",subs="+attributes"]
----
$ docker run -it --rm --name connect -p 8083:8083 -e GROUP_ID=1 -e CONFIG_STORAGE_TOPIC=my_connect_configs -e OFFSET_STORAGE_TOPIC=my_connect_offsets -e STATUS_STORAGE_TOPIC=my_connect_statuses --link zookeeper:zookeeper --link kafka:kafka --link mysql:mysql quay.io/debezium/connect:{debezium-docker-label}
----

`-it`:: The container is interactive,
which means the terminal's standard input and output are attached to the container.
`--rm`:: The container will be removed when it is stopped.
`--name connect`:: The name of the container.
`-p 8083:8083`:: Maps port `8083` in the container to the same port on the Docker host.
This enables applications outside of the container to use Kafka Connect's REST API to set up and manage new container instances.
`-e CONFIG_STORAGE_TOPIC=my_connect_configs -e OFFSET_STORAGE_TOPIC=my_connect_offsets -e STATUS_STORAGE_TOPIC=my_connect_statuses`:: Sets environment variables required by the {prodname} image.
`--link zookeeper:zookeeper --link kafka:kafka --link mysql:mysql`:: Links the container to the containers that are running ZooKeeper, Kafka, and the MySQL server.
--

ifdef::community[]
[NOTE]
====
If you use Podman, run the following command:
[source,shell,options="nowrap",subs="+attributes"]
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$ sudo podman run -it --rm --name connect --pod dbz -e GROUP_ID=1 -e CONFIG_STORAGE_TOPIC=my_connect_configs -e OFFSET_STORAGE_TOPIC=my_connect_offsets -e STATUS_STORAGE_TOPIC=my_connect_statuses quay.io/debezium/connect:{debezium-docker-label}
----
====
endif::community[]

[NOTE]
====
If you provide a `--hostname` command option then Kafka Connect REST API will *not* listen on the `localhost` interface.
This can cause issues when the REST port is being exposed.

If this is a problem then set environment variable `REST_HOST_NAME=0.0.0.0` which will ensure that REST API will be accessible from all interfaces.
====

. Verify that Kafka Connect started and is ready to accept connections.
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--
You should see output similar to the following:

[source,shell,options="nowrap"]
----
...
2020-02-06 15:48:33,939 INFO   ||  Kafka version: 3.0.0   [org.apache.kafka.common.utils.AppInfoParser]
...
2020-02-06 15:48:34,485 INFO   ||  [Worker clientId=connect-1, groupId=1] Starting connectors and tasks using config offset -1   [org.apache.kafka.connect.runtime.distributed.DistributedHerder]
2020-02-06 15:48:34,485 INFO   ||  [Worker clientId=connect-1, groupId=1] Finished starting connectors and tasks   [org.apache.kafka.connect.runtime.distributed.DistributedHerder]
----
--

. Use the Kafka Connect REST API to check the status of the Kafka Connect service.
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Kafka Connect exposes a REST API to manage {prodname} connectors.
To communicate with the Kafka Connect service,
you can use the `curl` command to send API requests to port 8083 of the Docker host (which you mapped to port 8083 in the `connect` container when you started Kafka Connect).
+
[NOTE]
====
These commands use `localhost`.
If you are using a non-native Docker platform (such as Docker Toolbox),
replace `localhost` with the IP address of your Docker host.
====

.. Open a new terminal and check the status of the Kafka Connect service:
+
--
[source,options="nowrap",subs="+attributes"]
----
$ curl -H "Accept:application/json" localhost:8083/
{"version":"{debezium-kafka-version}","commit":"cb8625948210849f"}  <1>
----
<1> The response shows that Kafka Connect version {debezium-kafka-version} is running.
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.. Check the list of connectors registered with Kafka Connect:
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--
[source,options="nowrap"]
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$ curl -H "Accept:application/json" localhost:8083/connectors/
[]  <1>
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<1> No connectors are currently registered with Kafka Connect.
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