Step by step of how to create mongo master-slave containers on linux:

1.Create a docker network

WhoAmI@WhoAmI:~$ docker network create my-mongo-cluster  

2.List all the docker networks

WhoAmI@WhoAmI:~$ docker network ls  

3.Execute and create three docker containers setting their names, their network and their image(mongodb)

WhoAmI@WhoAmI:~$ docker run -p 30500:27017 --name container1 --net my-mongo-cluster mongo mongod --replSet my-mongo-set  
WhoAmI@WhoAmI:~$ docker run -p 30501:27017 --name container2 --net my-mongo-cluster mongo mongod --replSet my-mongo-set  
WhoAmI@WhoAmI:~$ docker run -p 30502:27017 --name container3 --net my-mongo-cluster mongo mongod --replSet my-mongo-set

4.Configure container1 as master, the container2 and 3 as slaves on port 27017.

WhoAmI@WhoAmI:~$ config={"_id":"my-mongo-set","members":[{"_id":0,"host":"container1:27017"},{"_id":1,"host":"container2:27017"},{"_id":2,"host":"container3:27017"}]}  

5.initialize config

WhoAmI@WhoAmI:~$ rs.initiate(config)  

6.map port 27017 so you can acces inside the container

WhoAmI@WhoAmI:~$ docker run -d -p 27017:27017 mongo  

How to execute your mongo cluster:

1.First of all you must run all the containers

WhoAmI@WhoAmI:~$ docker start container1 container2 container3  

2.Now open 3(three) terminals and in each one execute 1(one) container on iterative mode

WhoAmI@WhoAmI:~$ docker exec -it container1 mongo  
WhoAmI@WhoAmI:~$ docker exec -it container2 mongo  
WhoAmI@WhoAmI:~$ docker exec -it container3 mongo  

terminal should looks like this:

my-mongo-set:PRIMARY>  
my-mongo-set:SECONDARY>  

3.On each terminal you should respectively initialize with

db = (new Mongo('container1:27017')).getDB('test')  
db = (new Mongo('container2:27017')).getDB('test')  
db = (new Mongo('container3:27017')).getDB('test')  

4.Now you must set container2 and container3 as slaves

db.setSlaveOk()  

5.Now it is ready! Have fun!

-Examples of operations on mongo:

db.Personagens.insert({"nome":'captain america',"raca":'human',"classe":'warrior',"vida":97})  
db.Personagens.find()  
db.Personagens.find().pretty()  
db.Personagens.find().count()  
db.Personagens.remove({})  

*If you want to use your cluster from outside it, you should use pymongo. The file geraCargaMongoDB.py has clear examples of how to use it!

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Passo a passo de como criar containers mongo (master-slave) no linux:

• Você deve executar com permissões de root

1.Crie uma rede docker

WhoAmI@WhoAmI:~$ docker network create my-mongo-cluster  

2.Liste as redes criadas

WhoAmI@WhoAmI:~$ docker network ls  

3.Execute e crie os containers setando o nome, a rede utilizada, a aplicacao mongo

WhoAmI@WhoAmI:~$ docker run -p 30500:27017 --name container1 --net my-mongo-cluster mongo mongod --replSet my-mongo-set  
WhoAmI@WhoAmI:~$ docker run -p 30501:27017 --name container2 --net my-mongo-cluster mongo mongod --replSet my-mongo-set  
WhoAmI@WhoAmI:~$ docker run -p 30502:27017 --name container3 --net my-mongo-cluster mongo mongod --replSet my-mongo-set

4.Aqui configure o container1 como mestre, e os dois restantes como escravos na porta 27017, padrao do mongo

WhoAmI@WhoAmI:~$ config={"_id":"my-mongo-set","members":[{"_id":0,"host":"container1:27017"},{"_id":1,"host":"container2:27017"},{"_id":2,"host":"container3:27017"}]}  

5.inicialize a configuracao definida

WhoAmI@WhoAmI:~$ rs.initiate(config)  

6.mapear a porta 27017 pra que possa acessar a mesma dentro do container

WhoAmI@WhoAmI:~$ docker run -d -p 27017:27017 mongo  

passo a passo de como executar:

1.Primeiramente você deve executar seus containers

WhoAmI@WhoAmI:~$ docker start container1 container2 container3  

2.Agora abra 3(três) terminais e em cada um executa 1(um) container no modo iterativo

WhoAmI@WhoAmI:~$ docker exec -it container1 mongo  
WhoAmI@WhoAmI:~$ docker exec -it container2 mongo  
WhoAmI@WhoAmI:~$ docker exec -it container3 mongo  

Deve aparecer algo como:

my-mongo-set:PRIMARY>  
my-mongo-set:SECONDARY>  

3.Em cada um dos terminais respectivamente você deve inicializar com

db = (new Mongo('container1:27017')).getDB('test')  
db = (new Mongo('container2:27017')).getDB('test')  
db = (new Mongo('container3:27017')).getDB('test')  

4.Agora você deve setar o container2 e o container3 como escravos(slave)

db.setSlaveOk()  

5.Pronto! divirta-se!

-Exemplos de operações com o mongo:

db.Personagens.insert({"nome":'captain america',"raca":'human',"classe":'warrior',"vida":97})  
db.Personagens.find()  
db.Personagens.find().pretty()  
db.Personagens.find().count()  
db.Personagens.remove({})  

*Se você deseja usar seu cluster de fora dos containers, utilize o pymongo. no arquivo geraCargaMongoDB.py, tem exemplos claros de como utilizar!