PSMDB - A MongoDB alternative for having Encryption At Rest

Encryption is the most popular tool for securing data both in transit and at rest.

- For protecting data in transit, we can configure to use the TLS connection

- For protecting data at rest, we can use Percona Server for MongoDB (PSMDB), an open-source alternative for MongoDB Enterprise.

License

PSMDB Docker images follow the SSPL license. Therefore, it is not a problem when I only have my containers deployed in on-premises environments.

Running MongoDB Replication on OpenShift

I have successfully installed the replication by following the guide Install Percona Server for MongoDB on OpenShift. In order to make it work properly with my needs, I disabled some features from the default deployment. See the detail in this change

Basically, I needed to create a CRD (Custom Resource Definition) to let OpenShift/Kubernetes what PSMDB is. Then, I deployed the Operator pod. Finally, I deployed the PSMDB StatefulSet. I used NFS shares for Persistent Volumes.

Create CRD for PSMDB

2git clone https://github.com/percona/percona-server-mongodb-operator 3cd percona-server-mongodb-operator 4 5# create Custom Resource Definition (CRD) with cluster-admin role 6# This task is needed to executed once 7oc apply -f deploy/crd.yaml

Deploy the Operator pod

2oc new-project psmdb 3 4# Add role-based access control (RBAC) 5oc apply -f deploy/rbac.yaml 6 7# deploy operator pod 8oc apply -f deploy/operator.yaml 9 10# Add secret 11oc create -f deploy/secrets.yaml

Create SealedSecret for local keyfile

(Assumed that SealedSecret is installed and ready for use)

By default, the operator generates a normal Kubernetes secret with the name "my-cluster-name-mongodb-encryption-key". This secret is automatically attached to the MongoDB StatefulSet and persisted as a file through volumes. The operator also handles passing the files to "mongod" command in the container entry point. We can replace the secret in the deployment templates "deploy/cr.yaml". For example:

1 security 2 enableEncryption: true 3 encryptionKeySecret: mongodb-encryption-key 4 encryptionCipherMode: AES256-CBC

Here is an example to create a SealedSecret "mongodb-encryption-key" locally and apply it to the project.

1 $ openssl rand -base64 32 > mongodb-keyfile 2$ cat mongodb-keyfile | kubectl create secret generic mongodb-encryption-key \ 3--dry-run=client --from-file=encryption-key=/dev/stdin \ 4-o yaml > mongodb-encryption-secret.yaml 5$ kubeseal < mongodb-encryption-secret.yaml > mongodb-encryption-sealed-secret.yaml 6$ oc create -f mongodb-encryption-sealed-secret.yaml

Install PSMDB StatefulSet

(Assumed that NFS is installed and ready for use)

Create NFS shares: data-0, data-1, and data-2. Here is a sample command for data-0

1$> ssh someuser@files.example.com.local 2$> sudo mkdir /srv/data/psmdb/mongodb/data-0 3$> sudo chown nfsnobody:0 /srv/data/psmdb/mongodb/data-0 4$> sudo chmod go+w /srv/data/psmdb/mongodb/data-0 5$> sudo chmod g+s /srv/data/psmdb/mongodb/data-0

The directory attributes should look like

drwxrwsrwx. 5 nfsnobody root 4096 Jun 24 03:31 data-0

drwxrwsrwx. 5 nfsnobody root 4096 Jun 24 03:30 data-1

drwxrwsrwx. 5 nfsnobody root 4096 Jun 24 03:31 data-2

Create corresponding Persistent Volumes with NFS shares

1kind: PersistentVolume 2apiVersion: v1 3metadata: 4 name: psmdb-mongodb-data-0 5spec: 6 capacity: 7 storage: 2Gi 8 nfs: 9 server: files.example.com.local 10 path: /srv/data/psmdb/mongodb/data-0 11 accessModes: 12 - ReadWriteOnce 13 persistentVolumeReclaimPolicy: Recycle 14 storageClassName: psmdb 15

Install the PSMDB StatefulSet

1 $> oc apply -f deploy/cr.yaml