Using AWS Secrets Manager CSI on ROSA with STS | Tutorials

Prerequisites
Preparing Environment
Deploy the AWS Secrets and Configuration Provider
Creating a Secret and IAM Access Policies
Create an Application to use this secret
Clean up

The AWS Secrets and Configuration Provider (ASCP) provides a way to expose AWS Secrets as Kubernetes storage volumes. With the ASCP, you can store and manage your secrets in Secrets Manager and then retrieve them through your workloads running on ROSA.

This is made even easier and more secure through the use of AWS STS and Kubernetes PodIdentity.

Prerequisites

A ROSA cluster deployed with STS
Helm 3
aws CLI
oc CLI
jq

Preparing Environment

Validate that your cluster has STS:
```
$ oc get authentication.config.openshift.io cluster -o json \
  | jq .spec.serviceAccountIssuer
```
You should see something like the following, if not you should not proceed, instead look to the Red Hat documentation on creating an STS cluster.
```
"https://xxxxx.cloudfront.net/xxxxx"
```

Set SecurityContextConstraints to allow the CSI driver to run:

$ oc new-project csi-secrets-store
$ oc adm policy add-scc-to-user privileged \
    system:serviceaccount:csi-secrets-store:secrets-store-csi-driver
$ oc adm policy add-scc-to-user privileged \
    system:serviceaccount:csi-secrets-store:csi-secrets-store-provider-aws

Create some environment variables to refer to later:

$ export REGION=$(oc get infrastructure cluster -o=jsonpath="{.status.platformStatus.aws.region}")
$ export OIDC_ENDPOINT=$(oc get authentication.config.openshift.io cluster \
   -o jsonpath='{.spec.serviceAccountIssuer}' | sed  's|^https://||')
$ export AWS_ACCOUNT_ID=`aws sts get-caller-identity --query Account --output text`
$ export AWS_PAGER=""

Deploy the AWS Secrets and Configuration Provider

Use Helm to register the secrets store CSI driver:

$ helm repo add secrets-store-csi-driver \
    https://kubernetes-sigs.github.io/secrets-store-csi-driver/charts

Update your Helm repositories:
```
$ helm repo update
```

Install the secrets store CSI driver:

$ helm upgrade --install -n csi-secrets-store \
    csi-secrets-store-driver secrets-store-csi-driver/secrets-store-csi-driver

Deploy the AWS provider:

$ oc -n csi-secrets-store apply -f \
    https://raw.githubusercontent.com/rh-mobb/documentation/main/content/misc/secrets-store-csi/aws-provider-installer.yaml

Check that both Daemonsets are running:

$ oc -n csi-secrets-store get ds \
    csi-secrets-store-provider-aws \
    csi-secrets-store-driver-secrets-store-csi-driver

Label the Secrets Store CSI Driver to allow use with the restricted pod security profile:

$ oc label csidriver.storage.k8s.io/secrets-store.csi.k8s.io security.openshift.io/csi-ephemeral-volume-profile=restricted

Creating a Secret and IAM Access Policies

Create a secret in Secrets Manager:

$ SECRET_ARN=$(aws --region "$REGION" secretsmanager create-secret \
    --name MySecret --secret-string \
    '{"username":"shadowman", "password":"hunter2"}' \
    --query ARN --output text)
$ echo $SECRET_ARN

Create an IAM Access Policy document:

$ cat << EOF > policy.json
{
   "Version": "2012-10-17",
   "Statement": [{
      "Effect": "Allow",
      "Action": [
        "secretsmanager:GetSecretValue",
        "secretsmanager:DescribeSecret"
      ],
      "Resource": ["$SECRET_ARN"]
      }]
}
EOF

Create an IAM Access Policy:

$ POLICY_ARN=$(aws --region "$REGION" --query Policy.Arn \
--output text iam create-policy \
--policy-name openshift-access-to-mysecret-policy \
--policy-document file://policy.json)
$ echo $POLICY_ARN

Create an IAM Role trust policy document:

The trust policy is locked down to the default service account of a namespace you will create later.

$ cat <<EOF > trust-policy.json
{
   "Version": "2012-10-17",
   "Statement": [
   {
   "Effect": "Allow",
   "Condition": {
     "StringEquals" : {
       "${OIDC_ENDPOINT}:sub": ["system:serviceaccount:my-application:default"]
      }
    },
    "Principal": {
       "Federated": "arn:aws:iam::$AWS_ACCOUNT_ID:oidc-provider/${OIDC_ENDPOINT}"
    },
    "Action": "sts:AssumeRoleWithWebIdentity"
    }
    ]
}
EOF

Create an IAM role:

$ ROLE_ARN=$(aws iam create-role --role-name openshift-access-to-mysecret \
--assume-role-policy-document file://trust-policy.json \
--query Role.Arn --output text)
$ echo $ROLE_ARN

Attach the role to the policy:

$ aws iam attach-role-policy --role-name openshift-access-to-mysecret \
    --policy-arn $POLICY_ARN

Create an Application to use this secret

Create an OpenShift project:
```
$ oc new-project my-application
```

Annotate the default service account to use the STS Role:

$ oc annotate -n my-application serviceaccount default \
    eks.amazonaws.com/role-arn=$ROLE_ARN

Create a secret provider class to access our secret:

$ cat << EOF | oc apply -f -
apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: my-application-aws-secrets
spec:
  provider: aws
  parameters:
    objects: |
      - objectName: "MySecret"
        objectType: "secretsmanager"
EOF

Create a Deployment using our secret:

$ cat << EOF | oc apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: my-application
  labels:
    app: my-application
spec:
  volumes:
  - name: secrets-store-inline
    csi:
      driver: secrets-store.csi.k8s.io
      readOnly: true
      volumeAttributes:
        secretProviderClass: "my-application-aws-secrets"
  containers:
  - name: my-application-deployment
    image: k8s.gcr.io/e2e-test-images/busybox:1.29
    command:
      - "/bin/sleep"
      - "10000"
    volumeMounts:
    - name: secrets-store-inline
      mountPath: "/mnt/secrets-store"
      readOnly: true
EOF

Verify the Pod has the secret mounted:

$ oc exec -it my-application -- cat /mnt/secrets-store/MySecret

Clean up

Delete the application:
```
$ oc delete project my-application
```

Delete the secrets store csi driver:

$ helm delete -n csi-secrets-store csi-secrets-store-driver

Delete Security Context Constraints:

$ oc adm policy remove-scc-from-user privileged \
    system:serviceaccount:csi-secrets-store:secrets-store-csi-driver
$ oc adm policy remove-scc-from-user privileged \
    system:serviceaccount:csi-secrets-store:csi-secrets-store-provider-aws

Delete the AWS provider:

$ oc -n csi-secrets-store delete -f \
https://raw.githubusercontent.com/rh-mobb/documentation/main/content/misc/secrets-store-csi/aws-provider-installer.yaml

Delete AWS Roles and Policies:

$ aws iam detach-role-policy --role-name openshift-access-to-mysecret \
    --policy-arn $POLICY_ARN
$ aws iam delete-role --role-name openshift-access-to-mysecret
$ aws iam delete-policy --policy-arn $POLICY_ARN

Delete the Secrets Manager secret:

$ aws secretsmanager --region $REGION delete-secret --secret-id $SECRET_ARN

Tutorial: Using AWS Secrets Manager CSI on ROSA with STS