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Description:

kafkaconnecthealthcheck 0.3.0

kafka-connect-healthcheck

A simple healthcheck wrapper to monitor Kafka Connect.

Kafka Connect Healthcheck is a server that wraps the Kafka Connect API and provides a singular API endpoint to determine the health of a Kafka Connect instance. This can be used to alert or take action on unhealthy connectors and tasks.
This can be used in numerous ways. It can sit as a standalone service for monitoring purposes, it can be used as a sidecar container to mark Kafka Connect workers as unhealthy in Kubernetes, or it can be used to provide logs of when connectors/tasks failed and reasons for their failures.
By default, the root endpoint / will return 200 OK healthy if all connectors and tasks are in a state other than FAILED. It will return 503 Service Unavailable if any connector or tasks are in a FAILED state.
Usage
Kafka Connect Healthcheck can be installed as a command-line tool through pip or it can be used as a standalone Docker container. It could also be installed as a part of a custom Kafka Connect docker image.
Command-Line
To use kafka-connect-healthcheck from the command-line, you must have python and pip installed. Currently, only Python 3 is supported.
You can install kafka-connect-healthcheck via pip:
pip install kafka-connect-healthcheck

To start the healthcheck server, run:
kafka-connect-healthcheck

The server will now be running on localhost:18083.
Docker
The kafka-connect-healthcheck image can be found on Docker Hub.
You can pull down the latest image by running:
docker pull devshawn/kafka-connect-healthcheck

To start the healthcheck server, run:
docker run --rm -it -p 18083:18083 devshawn/kafka-connect-healthcheck

The server will now be running on localhost:18083.
Configuration
Kafka Connect Healthcheck can be configured via command-line arguments or by environment variables.
Port
The port for the kafka-connect-healthcheck API.

Usage
Value

Environment Variable
HEALTHCHECK_PORT

Command-Line Argument
--port

Default Value
18083

Connect URL
The full URL of the Kafka Connect REST API. This is used to determine the health of the connect instance.

Usage
Value

Environment Variable
HEALTHCHECK_CONNECT_URL

Command-Line Argument
--connect-url

Default Value
http://localhost:8083

Connect Worker ID
The worker ID to monitor (usually the IP address of the connect worker). If none is set, all workers will be monitored and any failure will result in an unhealthy response.

Usage
Value

Environment Variable
HEALTHCHECK_CONNECT_WORKER_ID

Command-Line Argument
--connect-worker-id

Default Value
None (all workers monitored)

Note: It is highly recommended to run an instance of the healthcheck for each worker if you're planning to restart containers based on the health.
Considered Containers
A comma-separated list of which type of kafka connect container to be considered in the healthcheck calculation.

Usage
Value

Environment Variable
HEALTHCHECK_CONSIDERED_CONTAINERS

Command-Line Argument
--considered-containers

Default Value
CONNECTOR,TASK

Valid Values
CONNECTOR, TASK

Unhealthy States
A comma-separated list of connector and tasks states to be marked as unhealthy.

Usage
Value

Environment Variable
HEALTHCHECK_UNHEALTHY_STATES

Command-Line Argument
--unhealthy-states

Default Value
FAILED

Valid Values
FAILED, PAUSED, UNASSIGNED, RUNNING

Note: It's recommended to keep this defaulted to FAILED, but paused connectors or tasks can be marked as unhealthy by passing FAILED,PAUSED.
Failure Threshold Percentage
A number between 1 and 100. If set, this is the percentage of connectors that must fail for the healthcheck to fail.

Usage
Value

Environment Variable
HEALTHCHECK_FAILURE_THRESHOLD_PERCENTAGE

Command-Line Argument
--failure-threshold-percentage

Default Value
0

Valid Values
1 to 100

By default, any failures will cause the healthcheck to fail.
Log Level
The level of logs to be shown by the application.

Usage
Value

Environment Variable
HEALTHCHECK_LOG_LEVEL

Command-Line Argument
--log-level

Default Value
INFO

Valid Values
DEBUG, INFO, WARNING, ERROR

All healthy connector and task statuses are logged at INFO. Unhealthy ones are logged at WARNING. Any communication or HTTP errors are logged at ERROR.
API
The server provides a very simple HTTP API which can be used for liveness probes and monitoring alerts. We expose two endpoints:
GET /
Get the current health status of the Kafka Connect system. This could be used as a sidecar to determine the health of each Kafka Connect worker and their associated connectors and tasks.
Example Request
curl http://localhost:18083

Example Healthy Response
200 OK
{
"failures": [],
"failure_states": [
"FAILED"
],
"healthy": true
}

Example Unhealthy Response
503 Service Unavailable
{
"failures": [
{
"type": "connector",
"connector": "jdbc-source",
"state": "FAILED",
"worker_id": "127.0.0.1:8083"
},
{
"type": "task",
"connector": "jdbc-source",
"id": 0,
"state": "FAILED",
"worker_id": "127.0.0.1:8083",
"trace": "..."
}
],
"failure_states": [
"FAILED"
],
"healthy": false
}

GET /ping
Get the current health status of the healthcheck server. This will always be successful as long as the server is still able to serve requests. This can be used as a ready or liveness probe in Kubernetes.
Example Request
curl http://localhost:18083/ping

Example Response
200 OK
{
"status": "UP"
}

License
Copyright (c) 2019 Shawn Seymour.
Licensed under the Apache 2.0 license.