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Manage PostgreSQL Credentials Using the KubeVault Operator
PostgreSQL is one of the supported plugins for the database secrets engine. This plugin generates database credentials dynamically based on configured roles for the PostgreSQL database, and also supports Static Roles. You can easily manage PostgreSQL Database secret engine using the KubeVault operator.
You need to be familiar with the following CRDs:
Before you begin
- Install KubeVault operator in your cluster from here.
To keep things isolated, we are going to use a separate namespace called demo throughout this tutorial.
$ kubectl create ns demo
namespace/demo created
In this tutorial, we are going to create a role using PostgresRole and issue credential using DatabaseAccessRequest.
Vault Server
If you don’t have a Vault Server, you can deploy it by using the KubeVault operator.
The KubeVault operator can manage policies and secret engines of Vault servers which are not provisioned by the KubeVault operator. You need to configure both the Vault server and the cluster so that the KubeVault operator can communicate with your Vault server.
Now, we have the AppBinding that contains connection and authentication information about the Vault server.
$ kubectl get appbinding -n demo
NAME AGE
vault 50m
$ kubectl get appbinding -n demo vault -o yaml
apiVersion: appcatalog.appscode.com/v1alpha1
kind: AppBinding
metadata:
name: vault
namespace: demo
spec:
clientConfig:
caBundle: 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
service:
name: vault
port: 8200
scheme: HTTPS
parameters:
apiVersion: config.kubevault.com/v1alpha1
kind: VaultServerConfiguration
path: kubernetes
vaultRole: vault-policy-controller
kubernetes:
serviceAccountName: vault
tokenReviewerServiceAccountName: vault-k8s-token-reviewer
usePodServiceAccountForCSIDriver: true
Enable and Configure PostgreSQL Secret Engine
When a SecretEngine crd object is created, the KubeVault operator will enable a secret engine on specified path and configure the secret engine with given configurations.
A sample SecretEngine object for the PostgreSQL secret engine:
apiVersion: engine.kubevault.com/v1alpha1
kind: SecretEngine
metadata:
name: postgresql-engine
namespace: demo
spec:
vaultRef:
name: vault
path: my-postgres-se
postgres:
databaseRef:
name: postgres-app
namespace: demo
pluginName: postgresql-database-plugin
allowedRoles:
- "*"
To configure the PostgreSQL secret engine, you need to provide the PostgreSQL database connection and authentication information through an AppBinding.
$ kubectl get services -n demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
postgres ClusterIP 10.97.24.153 <none> 5432/TCP 86m
Let’s consider postgres is the Kubernetes service name that communicate with postgres servers. You can also connect to the database server using URL. Visit AppBinding documentation for more details. A sample AppBinding example with necessary k8s secret is given below:
apiVersion: appcatalog.appscode.com/v1alpha1
kind: AppBinding
metadata:
name: postgres-app
namespace: demo
spec:
secret:
name: postgres-user-cred # secret
clientConfig:
service:
name: postgres
scheme: postgresql
port: 5432
path: "postgres"
query: "sslmode=disable"
insecureSkipTLSVerify: true
---
apiVersion: v1
data:
username: cG9zdGdyZXM=
password: cm9vdA==
kind: Secret
metadata:
name: postgres-user-cred
namespace: demo
Let’s deploy SecretEngine:
$ kubectl apply -f docs/examples/guides/secret-engines/postgres/postgres-app.yaml
appbinding.appcatalog.appscode.com/postgres-app created
secret/postgres-user-cred created
$ kubectl apply -f docs/examples/guides/secret-engines/postgres/postgresSecretEngine.yaml
secretengine.engine.kubevault.com/postgresql-engine created
Wait till the status become Success:
$ kubectl get secretengines -n demo
NAME STATUS
postgresql-engine Success
Since the status is Success, the PostgreSQL secret engine is enabled and successfully configured. You can use kubectl describe secretengine -n <namepsace> <name> to check for error events, if any.
Create PostgreSQL Database Role
By using PostgresRole, you can create a role on the Vault server in Kubernetes native way.
A sample PostgresRole object is given below:
apiVersion: engine.kubevault.com/v1alpha1
kind: PostgresRole
metadata:
name: psql-role
namespace: demo
spec:
vaultRef:
name: vault
path: my-postgres-se
databaseRef:
name: postgres-app
namespace: demo
creationStatements:
- "CREATE ROLE \"{{name}}\" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}';"
- "GRANT SELECT ON ALL TABLES IN SCHEMA public TO \"{{name}}\";"
defaultTTL: 1h
maxTTL: 24h
Let’s deploy PostgresRole:
$ kubectl apply -f docs/examples/guides/secret-engines/postgres/postgresRole.yaml
postgresrole.engine.kubevault.com/psql-role created
$ kubectl get postgresrole -n demo
NAME AGE
psql-role 12s
You can also check from Vault that the role is created.
To resolve the naming conflict, name of the role in Vault will follow this format: k8s.{clusterName}.{metadata.namespace}.{metadata.name}.
Don’t have Vault CLI? Download and configure it as described here
$ vault list my-postgres-se/roles
Keys
----
k8s.-.demo.psql-role
$ vault read my-postgres-se/roles/k8s.-.demo.psql-role
Key Value
--- -----
creation_statements [CREATE ROLE "{{name}}" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}'; GRANT SELECT ON ALL TABLES IN SCHEMA public TO "{{name}}";]
db_name k8s.-.demo.postgres-app
default_ttl 1h
max_ttl 24h
renew_statements []
revocation_statements []
rollback_statements []
If we delete the PostgresRole, then the respective role will be deleted from the Vault.
$ kubectl delete postgresrole -n demo psql-role
postgresrole.engine.kubevault.com "psql-role" deleted
Check from Vault whether the role exists:
$ vault read my-postgres-se/roles/k8s.-.demo.psql-role
No value found at my-postgres-se/roles/k8s.-.demo.psql-role
$ vault list my-postgres-se/roles
No value found at my-postgres-se/roles/
Generate PostgreSQL Database Credentials
By using DatabaseAccessRequest, you can generate database access credentials from Vault.
Here, we are going to make a request to Vault for PostgreSQL database credentials by creating postgres-cred-rqst DatabaseAccessRequest in demo namespace.
apiVersion: engine.kubevault.com/v1alpha1
kind: DatabaseAccessRequest
metadata:
name: postgres-cred-rqst
namespace: demo
spec:
roleRef:
kind: PostgresRole
name: psql-role
namespace: demo
subjects:
- kind: ServiceAccount
name: demo-sa
namespace: demo
Here, spec.roleRef is the reference of PostgresRole against which credentials will be issued. spec.subjects is the reference to the object or user identities a role binding applies to and it will have read access of the credential secret.
Now, we are going to create DatabaseAccessRequest.
$ kubectl apply -f docs/examples/guides/secret-engines/postgres/postgresAccessRequest.yaml
databaseaccessrequest.engine.kubevault.com/postgres-cred-rqst created
$ kubectl get databaseaccessrequest -n demo
NAME AGE
postgres-cred-rqst 34s
Database credentials will not be issued until it is approved. The KubeVault operator will watch for the approval in the status.conditions[].type field of the request object. You can use KubeVault CLI, a kubectl plugin, to approve or deny DatabaseAccessRequest.
# using KubeVault CLI as kubectl plugin to approve request
$ kubectl vault approve databaseaccessrequest postgres-cred-rqst -n demo
approved
$ kubectl get databaseaccessrequest -n demo postgres-cred-rqst -o yaml
apiVersion: engine.kubevault.com/v1alpha1
kind: DatabaseAccessRequest
metadata:
name: postgres-cred-rqst
namespace: demo
spec:
roleRef:
kind: PostgresRole
name: psql-role
namespace: demo
subjects:
- kind: ServiceAccount
name: demo-sa
namespace: demo
status:
conditions:
- lastUpdateTime: "2019-11-20T11:40:26Z"
message: This was approved by kubectl vault approve databaseaccessrequest
reason: KubectlApprove
type: Approved
lease:
duration: 1h0m0s
id: my-postgres-se/creds/k8s.-.demo.psql-role/chQO2c89Wf2zieXYA9KoL9sb
renewable: true
secret:
name: postgres-cred-rqst-pmq5gp
Once DatabaseAccessRequest is approved, the KubeVault operator will issue credentials from Vault and create a secret containing the credential. It will also create a role and rolebinding so that spec.subjects can access secret. You can view the information in the status field.
$ kubectl get databaseaccessrequest postgres-cred-rqst -n demo -o json | jq '.status'
{
"conditions": [
{
"lastUpdateTime": "2019-11-20T11:40:26Z",
"message": "This was approved by kubectl vault approve databaseaccessrequest",
"reason": "KubectlApprove",
"type": "Approved"
}
],
"lease": {
"duration": "1h0m0s",
"id": "my-postgres-se/creds/k8s.-.demo.psql-role/chQO2c89Wf2zieXYA9KoL9sb",
"renewable": true
},
"secret": {
"name": "postgres-cred-rqst-pmq5gp"
}
}
$ kubectl get secret -n demo postgres-cred-rqst-pmq5gp -o yaml
apiVersion: v1
data:
password: QTFhLWdxYTBCeExneXdjS1hkRmI=
username: di1rdWJlcm5ldC1rOHMuLS5kZS1lWmlkSFloyNUNUQy0xNTc0MjUwMDI2
kind: Secret
metadata:
name: postgres-cred-rqst-pmq5gp
namespace: demo
ownerReferences:
- apiVersion: engine.kubevault.com/v1alpha1
controller: true
kind: DatabaseAccessRequest
name: postgres-cred-rqst
uid: a13e98a9-22d9-4e81-975e-a8408d8cb380
type: Opaque
If DatabaseAccessRequest is deleted, then credential lease (if any) will be revoked.
$ kubectl delete databaseaccessrequest -n demo postgres-cred-rqst
databaseaccessrequest.engine.kubevault.com "postgres-cred-rqst" deleted
If DatabaseAccessRequest is Denied, then the KubeVault operator will not issue any credential.
$ kubectl vault deny databaseaccessrequest postgres-cred-rqst -n demo
Denied
Note: Once DatabaseAccessRequest is
ApprovedorDenied, you cannot changespec.roleRefandspec.subjectsfield.