Running MongoDB with persistent storage

MongoDB is a good example of an application that would benefit from running in a Nitro Enclave and using Anjuna Nitro Runtime’s persistent storage features.

In this example, we simplify a MongoDB inside a Nitro Enclave setup and ignore TLS configuration and encryption. We will focus on running a MongoDB server with persistent storage to learn how to work with persistent storage with Nitro Enclaves.

Let’s get started!

Build the required tools for volume mounts support

If you haven’t done so, start the anjuna-nitro-netd-parent agent first.

Run the following commands to build the tools required to support volume mounts:

cd /opt/anjuna/nitro/drbd/
./parent-drbd-setup.sh -build

Create a persistent volume disk file

To create a fresh new volume disk file to save the persistent data, run the following commands:

cd /opt/anjuna/nitro/drbd/
# Create a 2048 MB disk file for the volume
./parent-drbd-setup.sh -mem 2048 -disk-create ~/nitro-disk.img

# start the parent listener
./parent-drbd-setup.sh -start ~/nitro-disk.img

Install MongoDB Shell

Before running our MongoDB server, let’s get a tool that will allow us to interact with the MongoDB server.

Create a file at /etc/yum.repos.d/mongodb-org-5.0.repo. You’ll need root access to write that file, so you can run sudo vim /etc/yum.repos.d/mongodb-org-5.0.repo

Copy the following contents into the file and save it:

[mongodb-org-5.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/amazon/2/mongodb-org/5.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-5.0.asc

Now we can install the MongoDB Shell:

sudo yum install -y mongodb-org-shell

Building the enclave

In this section we build a MongoDB enclave that uses a persistent volume mount.

Create an enclave configuration file and name it enclave-config.yaml. This file configures MongoDB to bind to all IPs, sets a default username and password for the database and mounts the volume mount to /data/db, where Mongo expects the DB files to be.

version: 1.6

# Run mongodb, bind to all IPs
command: [docker-entrypoint.sh, mongod, --auth, --port=27017, --bind_ip=0.0.0.0]

# Set a default MongoDB username and password
environment:
- MONGO_INITDB_ROOT_USERNAME=anjuna
- MONGO_INITDB_ROOT_PASSWORD=anjuna

# Set a persistent volume mount
mounts:
  - type: block
    name: db-volume
    mountPath: /data/db

Build and run the enclave:

# Build the enclave using the mongo:latest Docker image,
# enclave-config.yaml as the enclave configuration file,
# and save it to mongo-nitro.eif
anjuna-nitro-cli build-enclave --docker-uri mongo:latest --enclave-config-file enclave-config.yaml --output-file mongo-nitro.eif

# Start the network agent
anjuna-nitro-netd-parent --expose 27017 --daemonize

# Start the enclave we just created
anjuna-nitro-cli run-enclave --cpu-count 2 --memory 4096 --eif-path mongo-nitro.eif --debug-mode

The number of vCPU cores must be an even number due to hyperthreading.

If the agent is already running, it should be killed before starting the enclave.

Connecting to the database

After a few seconds of initialization, you should be able to connect to the MongoDB. Let’s connect and add some data. If you’re unable to connect, wait a few more seconds and try again.

$ mongo -u anjuna -p anjuna 'mongodb://localhost'
> use demo
> db.data.insert({"hello_world":1})
> db.data.findOne()
> exit

We have added some data and we’re able to query it. Great! Now we can make sure the data is staying persistent. To do that, we can terminate the enclave and run it again.

$ anjuna-nitro-cli terminate-enclave --all

$ anjuna-nitro-cli run-enclave --cpu-count 2 --memory 4096 --eif-path mongo-nitro.eif --debug-mode

After 20-30 seconds, we should be able to connect to the DB and fetch the data we inserted before terminating the enclave:

$ mongo -u anjuna -p anjuna 'mongodb://localhost'
> use demo
> db.data.findOne()
> exit

You should be able to see the entry we created before: { "_id" : ObjectId("…."), "hello_world" : 1 }

Congratulations! You have successfully set up a Nitro Enclave with a persistent storage volume.