bigchaindb/k8s/mongodb/container

Custom MongoDB container for BigchainDB Backend

Need

• MongoDB needs the hostname provided in the rs.initiate() command to be resolvable through the hosts file locally.
• In the future, with the introduction of TLS for inter-cluster MongoDB communications, we will need a way to specify detailed configuration.
• We also need a way to overwrite certain parameters to suit our use case.

Step 1: Build the Latest Container

make from the root of this project.

Step 2: Run the Container

docker run \
--name=mdb1 \
--publish=<mongo port number for external connections>:<corresponding host port> \
--rm=true \
bigchaindb/mongodb \
--replica-set-name <replica set name> \
--fqdn <fully qualified domain name of this instance> \
--port <mongod port number for external connections>

Step 3: Initialize the Replica Set

Login to one of the MongoDB containers, say mdb1:

docker exec -it mdb1 bash

Start the mongo shell:

mongo --port 27017

Run the rs.initiate() command:

rs.initiate({ 
  _id : "<replica-set-name", members: [
  { 
    _id : 0,
    host : "<fqdn of this instance>:<port number>"
  } ]
})

For example:

rs.initiate({ _id : "test-repl-set", members: [ { _id : 0, host :
"mdb-instance-0.westeurope.cloudapp.azure.com:27017" } ] })

You should also see changes in the mongo shell prompt from > to test-repl-set:OTHER> to test-repl-set:SECONDARY> to finally test-repl-set:PRIMARY>. If this instance is not the primary, you can use the rs.status() command to find out who is the primary.

Step 4: Add members to the Replica Set

We can only add members to a replica set from the PRIMARY instance. Login to the PRIMARY and open a mongo shell.

Run the rs.add() command with the ip and port number of the other containers/instances:

rs.add("<fqdn>:<port>")

For example:

Add mdb2 to replica set from mdb1:

rs.add("bdb-cluster-1.northeurope.cloudapp.azure.com:27017")

Add mdb3 to replica set from mdb1:

rs.add("bdb-cluster-2.northeurope.cloudapp.azure.com:27017")