In this blog post you are going to see how you can declare your entire Kafka environment and data flows as just declarative configuration in a GitOps fashion.
This means you can deploy flows and Kafka in a repeatable and standardised fashion across your different environments.
Read Andrew’s part 1 of our blog of GitOps for Kafka with Lenses: Part 1
Pre-requisites.
You’re going to need Lenses and the Lenses CLI client.
As a quick reminder, Lenses provides a powerful, secure UI and APIs to explore, manage, monitor, troubleshoot Kafka and your data streams. It’s just a small 4GB JVM that you point to your Kafka and Kubernetes (if you have one) clusters.
But to make it easier to follow this guide just download the best Kafka development tool as a docker container
You can get the Lenses CLI from here.
Getting started with Lenses CLI
Two appropriate places to put the lenses-cli
~/bin
/usr/local/bin
lenses-cli
PATH
lenses-cli
As this blog post is going to use a macOS machine, the following commands were
executed for installing Lenses CLI in /usr/local/bin
```
$ wget https://github.com/Landoop/lenses-go/releases/download/2.3.4/lenses-cli-darwin-amd64.tar.gz
$ tar zxvf lenses-cli-darwin-amd64.tar.gz
x lenses-cli-darwin-amd64
$ mv lenses-cli-darwin-amd64 /usr/local/bin/lenses-cli
```
If you are using lenses-cli
lenses-cli configure
lenses-cli
Basic lenses-cli usage
First, execute lenses-cli configure
```
__ ________ ____
/ / ___ ____ ________ _____ / ____/ / / _/
/ / / _ \/ __ \/ ___/ _ \/ ___/ / / / / / /
/ /___/ __/ / / (__ ) __(__ ) / /___/ /____/ /
/_____/\___/_/ /_/____/\___/____/ \____/_____/___/
Docs at https://docs.lenses.io
? Enable debug mode? No
? Enable insecure https connections? Yes
? Host http://localhost:3030
? How would you like to be authenticated? lenses BASIC auth or LDAP (default)
? Username admin
? Password [? for help] *****
```Notice that the information you gave to lenses-cli configure
~/.lenses/lenses-cli.yml
Executing lenses-cli version
lenses-cli
```
$ lenses-cli version
lenses-cli 2.3.4
>>>> build
revision 04647909dbcdaa19a7c98720a6a9a918dad2187b
datetime Fri Jul 12 11:34:03 EEST 2019
go go1.12
```Adding resources
The lenses-cli
lenses-cli
For the purposes of this blog post, we are going to execute the following
lenses-cli
```
$ lenses-cli connector create log_bloker.yaml
Loading from file 'log_bloker.yaml'
Connector [file-connector] created
```
The contents of the connector configuration file, which is saved in log_bloker.yaml
```
clusterName: dev
config:
name: file-connector
connector.class: org.apache.kafka.connect.file.FileStreamSourceConnector
tasks.max: 1
config.action.reload: RESTART
errors.log.include.messages: false
file: /var/log/broker.log
topic: var_log_broker
batch.size: 2000
```Notice that the default clusterName
dev
clusterName
You can verify that the desired connector is created by executing the following command:
```
$ lenses-cli connectors --cluster-name=dev
CLUSTER NAME CONFIGS TASKS
--------- ---------------- --------- -------
dev file-connector 8 1
dev logs-broker 5 1
dev nullsink 5 4
```
Alternatively, you can visit Lenses GUI and see the available connectors.
If you try to execute the same command again, it will fail with the next error message:
```
$ lenses-cli connector create logs_broker.yaml
Loading from file 'logs_broker.yaml'
connector file-connector already exists
```
The last line of the output states the cause of the error - a connector with the same
name already exists (connector file-connector already exists
As logs_broker.yaml
Exporting
The lenses-cli
In this case we are going to export resources using the following lenses-cli
```
$ lenses-cli export topics --dir export
$ lenses-cli export processors --dir export
$ lenses-cli export quotas --dir export
$ lenses-cli export connectors --dir export
$ lenses-cli export schemas --dir export
$ lenses-cli export policies --dir export
```
This command exports all available topics, processors, quotas, connectors, schemas and
policies and puts them under the export
lenses-cli
The next command will export the logs-broker
```
$ lenses-cli export connectors --resource-name=logs-broker --cluster-name
dev --dir export
```
The output of the tree(1)
export
lenses-cli export
```
$ tree -d export
export
├── apps
│ ├── connectors
│ └── sql
├── kafka
│ ├── quotas
│ └── topics
├── policies
└── schemas
8 directories
```
Notice that the name of the directory that the data will be saved is defined as
the value of the --dir
lenses-cli export
Pushing using git
Provided that we have a GitHub repository, we can clone it using git clone
export
```
$ git add .
$ git commit -a -m "Storing export directory"
$ git push
```
Pulling from git
First, we will need to get the data from GitHub and store in on our local machine. This can be done by executing the following command:
```
$ git clone <URL of GitHub repository>
$ cd <directory of GitHub repository>
```
Now, that we have the configuration on our local machine, we are ready to transfer that information to an empty Lenses Box, which will be illustrated in the next section.
Notice that the name of the directory that contains the Lenses configuration data
will be given as a command line parameter to all lenses-cli import
--dir
Importing
In this section we are going to use a Lenses Box. The main advantage we get from using a Lenses Box is that it is a Docker image that we can experiment with without the fear of destroying a working Lenses installation.
After exporting the desired configuration data, we will be able to import all of it
using multiple lenses-cli import
```
$ lenses-cli import processors --dir export
$ lenses-cli import topics --dir export
$ lenses-cli import schemas --dir export
$ lenses-cli import policies --dir export
$ lenses-cli import connectors --dir export
$ lenses-cli import quotas --dir export
```
If you execute the lenses import policies
Conclusions
The lenses-cli
lenses-cli
Download the best DataOps development tool which comes with a free for developers version of Lenses and a Kafka environment as a single docker container.
