Getting Started with Helm Charts (ScalarDB Cluster with TLS by Using cert-manager)
This tutorial explains how to get started with ScalarDB Cluster with TLS configurations by using Helm Charts and cert-manager on a Kubernetes cluster in a test environment. Before starting, you should already have a Mac or Linux environment for testing. In addition, although this tutorial mentions using minikube, the steps described should work in any Kubernetes cluster.
Requirements
- You need to have a license key (trial license or commercial license) for ScalarDB Cluster. If you don't have a license key, please contact us.
- You need to use ScalarDB Cluster 3.12 or later, which supports TLS.
What you'll create
In this tutorial, you'll deploy the following components on a Kubernetes cluster in the following way:
+----------------------------------------------------------------------------------------------------------------------------------------------------+
| [Kubernetes Cluster] |
| [Pod] [Pod] [Pod] |
| |
| +-------+ +------------------------+ |
| +---> | Envoy | ---+ +---> | ScalarDB Cluster node | ---+ |
| [Pod] | +-------+ | | +------------------------+ | |
| | | | | |
| +-----------+ +---------+ | +-------+ | +--------------------+ | +------------------------+ | +---------------+ |
| | Client | ---> | Service | ---+---> | Envoy | ---+---> | Service | ---+---> | ScalarDB Cluster node | ---+---> | PostgreSQL | |
| | (SQL CLI) | | (Envoy) | | +-------+ | | (ScalarDB Cluster) | | +------------------------+ | | (For Ledger) | |
| +-----------+ +---------+ | | +--------------------+ | | +---------------+ |
| | +-------+ | | +------------------------+ | |
| +---> | Envoy | ---+ +---> | ScalarDB Cluster node | ---+ |
| +-------+ +------------------------+ |
| |
| +----------------------------------------------------------------------------------+ +---------------------+ |
| | cert-manager (create private key and certificate for Envoy and ScalarDB Cluster) | | Issuer (Private CA) | |
| +----------------------------------------------------------------------------------+ +---------------------+ |
| |
+----------------------------------------------------------------------------------------------------------------------------------------------------+
cert-manager automatically creates the following private key and certificate files for TLS connections.
+----------------------+
+---> | For Scalar Envoy |
| +----------------------+
| | tls.key |
| | tls.crt |
+-------------------------+ | +----------------------+
| Issuer (Self-signed CA) | ---(Sign certificates)---+
+-------------------------+ | +----------------------+
| tls.key | +---> | For ScalarDB Cluster |
| tls.crt | +----------------------+
| ca.crt | | tls.key |
+-------------------------+ | tls.crt |
+----------------------+
Scalar Helm Charts automatically mount each private key and certificate file for Envoy and ScalarDB Cluster as follows to enable TLS in each connection. You'll manually mount a root CA certificate file on the client.
+-------------------------------------+ +------------------------------------------------+ +--------------------------------+
| Client | ---(CRUD/SQL requests)---> | Envoy for ScalarDB Cluster | ---> | ScalarDB Cluster nodes |
+-------------------------------------+ +------------------------------------------------+ +--------------------------------+
| ca.crt (to verify tls.crt of Envoy) | | tls.key | | tls.key |
+-------------------------------------+ | tls.crt | | tls.crt |
| ca.crt (to verify tls.crt of ScalarDB Cluster) | | ca.crt (to check health) |
+------------------------------------------------+ +--------------------------------+
The following connections exist amongst the ScalarDB Cluster–related components:
Client - Envoy for ScalarDB Cluster
: When you execute a CRUD API or SQL API function, the client accesses Envoy for ScalarDB Cluster.Envoy for ScalarDB Cluster - ScalarDB Cluster
: Envoy works as an L7 (gRPC) load balancer in front of ScalarDB Cluster.ScalarDB Cluster node - ScalarDB Cluster node
: A ScalarDB Cluster node accesses other ScalarDB Cluster nodes. In other words, the cluster's internal communications exist amongst all ScalarDB Cluster nodes.
Step 1. Start a Kubernetes cluster and install tools
You need to prepare a Kubernetes cluster and install some tools (kubectl
, helm
, cfssl
, and cfssljson
). For more details on how to install them, see Getting Started with Scalar Helm Charts.
Step 2. Start the PostgreSQL containers
ScalarDB Cluster must use some type of database system as a backend database. In this tutorial, you'll use PostgreSQL.
You can deploy PostgreSQL on the Kubernetes cluster as follows:
-
Add the Bitnami helm repository.
helm repo add bitnami https://charts.bitnami.com/bitnami
-
Deploy PostgreSQL for ScalarDB Cluster.
helm install postgresql-scalardb-cluster bitnami/postgresql \
--set auth.postgresPassword=postgres \
--set primary.persistence.enabled=false \
-n default -
Check if the PostgreSQL containers are running.
kubectl get pod -n default
[Command execution result]
NAME READY STATUS RESTARTS AGE
postgresql-scalardb-cluster-0 1/1 Running 0 34s
Step 3. Create a working directory
You'll create some configuration files locally. Be sure to create a working directory for those files.
-
Create a working directory.
mkdir -p ${HOME}/scalardb-cluster-test/
Step 4. Deploy cert-manager and issuer resource
This tutorial uses cert-manager to issue and manage your private keys and certificates. You can deploy cert-manager on the Kubernetes cluster as follows:
-
Add the Jetstack helm repository.
helm repo add jetstack https://charts.jetstack.io
-
Deploy cert-manager.
helm install cert-manager jetstack/cert-manager \
--create-namespace \
--set installCRDs=true \
-n cert-manager -
Check if the cert-manager containers are running.
kubectl get pod -n cert-manager
[Command execution result]
NAME READY STATUS RESTARTS AGE
cert-manager-6dc66985d4-6lvtt 1/1 Running 0 26s
cert-manager-cainjector-c7d4dbdd9-xlrpn 1/1 Running 0 26s
cert-manager-webhook-847d7676c9-ckcz2 1/1 Running 0 26s -
Change the working directory to
${HOME}/scalardb-cluster-test/
.cd ${HOME}/scalardb-cluster-test/
-
Create a custom values file for the private CA (
private-ca-custom-values.yaml
).cat << 'EOF' > ${HOME}/scalardb-cluster-test/private-ca-custom-values.yaml
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
name: self-signed-issuer
spec:
selfSigned: {}
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
name: self-signed-ca-cert
spec:
isCA: true
commonName: self-signed-ca
secretName: self-signed-ca-cert-secret
privateKey:
algorithm: ECDSA
size: 256
issuerRef:
name: self-signed-issuer
kind: Issuer
group: cert-manager.io
---
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
name: self-signed-ca
spec:
ca:
secretName: self-signed-ca-cert-secret
EOF -
Deploy a self-signed CA.
kubectl apply -f ./private-ca-custom-values.yaml
-
Check if the issuer resources are
True
.kubectl get issuer
[Command execution result]
NAME READY AGE
self-signed-ca True 6s
self-signed-issuer True 6s