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https://github.com/danielepalaia/web-service-kubernetes

Experiments on kubernetes, minikube, docker, golang, rest-api
https://github.com/danielepalaia/web-service-kubernetes

docker go golang kubernetes minikube mysql rest-api

Last synced: 5 days ago
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Experiments on kubernetes, minikube, docker, golang, rest-api

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README 

        
# Introduction



Scope of this software is just to play around with Kubernetes (Minikube). 

This software is exposing a set of rest-api to manage a collection of ToDo operations and is accessing mysql to store and read Todos. 

We will see how this app can be deployed locally, using just Docker containers to link one container to another or using kubernetes, minikube in this case. 

In the past I also used this app deployed on Pivotal CF: 

https://github.com/DanielePalaia/cf-mysql-example 



## Datastore and rest api



The todos operations are saved in a mysql datastore defined in datastore.sql



```

CREATE TABLE ToDo (

	    ID int NOT NULL AUTO_INCREMENT,

	    Topic varchar(255),

	    Completed int,

	    Due varchar(255) DEFAULT '',

	    PRIMARY KEY (ID)

);

```



The software exposes these rest api (GET, POST, PUT, DELETE) which can be tested with curl.

Use GET to get all todo items inside the collection 

Use POST to create a new item for the Todo Collection 

Use PUT for update and DELETE for deletion 



```

curl http://localhost:8080/todos

curl -H "Content-Type: application/json" -d '{"Topic":"New TodoElem", "Completed":0}' -X POST http://localhost:8080/todos

curl http://localhost:8080/todos/1

curl -H "Content-Type: application/json" -d '{"Id":0,"name":"New TodoElem Updated"}' -X PUT http://localhost:8080/todos

curl -X DELETE http://localhost/todos/1

curl -X DELETE http://localhost/todos

```

 

## Running the app on docker containers only

### 1. Create a mysql docker like this: 

Docker file is already provided you can just: 

```

docker run -p 3306:3306 --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql/mysql-server:5.7

```

### 2. Create database and new user

Enter inside the docker created and create the datastore as done locally 

```

docker exec -it some-mysql mysql -uroot -p

```



After this create a new use and grant privileges on the database just created 

GRANT ALL PRIVILEGES ON *.* TO 'daniele'@'%' IDENTIFIED BY 'daniele' WITH GRANT OPTION;

Do now a docker inspect some-mysql and get the ip of the docker image 

### 3. Configure input properties 

Now collect all this info (username, password and ip and put it in the program configuration file ./conf

### 4. Run the software in a docker container and link to mysql

A dockerfile is provided



```

sudo  docker build -t web-service-kubernetes .

docker run --publish 6060:8080 --name test --link some-mysql:mysql --rm web-service-kubernetes

```



This will now listen on port 6060 use curl as done before to test it...

### 5. Test the rest api as before



 

## Running on kubernetes (minikube)



### 1. Putting the docker image on dockerhub

I already created a dockerhub repository. In my case will be:

https://cloud.docker.com/repository/registry-1.docker.io/danielepalaia/web-service-kubernetes

docker push danielepalaia/web-service-kubernetes



### 2. Install minikube

Minikube allows you to have and manage a local kubernetes cluster 

Follow this guide to install minikube on ubuntu 

https://linuxhint.com/install-minikube-ubuntu/



Run minikube start and minikube dashboard to run the dashboard 

 ![Screenshot](./images/image2.png)



### 3. Create a volume, a pod and a service for mysql

Follow this guide on how to create a mysql pod and service

https://kubernetes.io/docs/tasks/run-application/run-single-instance-stateful-application/

Basically we need to create a Volume for mysql and a service for mysql. 

I put .yaml file in kubernetes-yaml folder. 

you can kubectl --apply to the volume first and then to the service 



```

kubectl apply -f ./mysql-pv.yaml

kubectl apply -f ./mysql-deployment.yaml

```



The first one will create a volume while the second one will create a deployment, a pod and a service for mysql.



### 4. Go inside mysql and create database and table as for datastore.sql

To do this you can create a mysql client to connect to the server 



```

kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -ppassword

```



This will prompt you inside the mysql server where you can create database and table.



 



### 5. Create a pod for this service web-service-kubernetes

I usually the minikube dashboard, you can go to new and specify as image danielepalaia/web-service-kubernetes



![Screenshot](./images/image1.png)



### 6. Forward the port from pod locally

Apparently minikube doesn't support services of type LoadBalancer... so we must just use one pod forwarding the port.

kubectl port-forward pod-name 8080:8080



### 7. You can then use the rest api as before from your localhost



## Useful kubernetes command



1) Getting the shell from a container 



kubectl exec -it my-pod -- /bin/bash 



with docker instead: 



docker ps to take the id of the container



docker exec -it docker-id bash



## Automation with Ansible (ToDo)

ToDo: start playing some automation with ansible...