How to access Redis as a k8s service with NestJS TypeORM's cache server option? - kubernetes

Question

I'd like to deploy my k8s with NestJS backend server and redis.
In order to remove user service from the core service of NestJS, I would like to run user service as a service of k8s, and use the cache server of user db referenced by the user service as a service in k8s.
To do that, I set up the user service's database config module like this.
import { Module } from '#nestjs/common'
import { TypeOrmModule, TypeOrmModuleAsyncOptions, TypeOrmModuleOptions } from '#nestjs/typeorm'
import { SnakeNamingStrategy } from 'typeorm-naming-strategies'
let DATABASE_NAME = 'test'
if (process.env.NODE_ENV) {
DATABASE_NAME = `${DATABASE_NAME}_${process.env.NODE_ENV}`
}
const DB_HOST: string = process.env.DB_HOST ?? 'localhost'
const DB_USERNAME: string = process.env.DB_USERNAME ?? 'user'
const DB_PASSWORD: string = process.env.DB_PASSWORD ?? 'password'
const REDIS_HOST: string = process.env.REDIS_HOST ?? 'localhost'
const databaseConfig: TypeOrmModuleAsyncOptions = {
useFactory: (): TypeOrmModuleOptions => ({
type: 'mysql',
host: DB_HOST,
port: 3306,
username: DB_USERNAME,
password: DB_PASSWORD,
database: DATABASE_NAME,
autoLoadEntities: true,
synchronize: true,
namingStrategy: new SnakeNamingStrategy(),
logging: false,
cache: {
type: 'redis',
options: {
host: REDIS_HOST,
port: 6379,
},
},
timezone: '+09:00',
}),
}
#Module({
imports: [
TypeOrmModule.forRootAsync({
...databaseConfig,
}),
],
})
export class DatabaseModule {}
And, to implement k8s I used a helm.
Helm's template folders are as follows.
- configmap
- deployment
- pod
- service
And, under those folders are as follows.
// configmap/redis.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: redis-config
data:
redis-config: |
maxmemory 20mb
maxmemory-policy allkeys-lru
// deployment/user_service.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: user-service
labels:
app: user-service
namespace: default
spec:
replicas: {{ .Values.replicas }}
selector:
matchLabels:
app: user-service
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
labels:
app: user-service
spec:
containers:
- image: {{ .Values.user_service.image }}:{{ .Values.user_service_version }}
imagePullPolicy: Always
name: user-service
ports:
- containerPort: 50051
protocol: TCP
env:
- name: COGNITO_CLIENT_ID
value: "some value"
- name: COGNITO_USER_POOL_ID
value: "some value"
- name: DB_HOST
value: "some value"
- name: DB_PASSWORD
value: "some value"
- name: DB_USERNAME
value: "some value"
- name: NODE_ENV
value: "test"
- name: REDIS_HOST
value: "10.100.77.0"
// pod/redis.yaml
apiVersion: v1
kind: Pod
metadata:
name: redis
labels:
app: redis
spec:
containers:
- name: redis
image: redis:latest
command:
- redis-server
- "/redis-master/redis.conf"
env:
- name: MASTER
value: "true"
ports:
- containerPort: 6379
name: redis
volumeMounts:
- mountPath: /redis-master-data
name: data
- mountPath: /redis-master
name: config
volumes:
- name: data
emptyDir: {}
- name: config
configMap:
name: redis-config
items:
- key: redis-config
path: redis.conf
// service/user_service.yaml
apiVersion: v1
kind: Service
metadata:
name: user-service
spec:
clusterIP: 10.100.88.0
selector:
app: user-service
ports:
- protocol: TCP
port: 50051
targetPort: 50051
// service/redis.yaml
apiVersion: v1
kind: Service
metadata:
name: redis
labels:
app: redis
spec:
clusterIP: 10.100.77.0
selector:
app: redis
ports:
- name: redis
protocol: TCP
port: 6379
targetPort: 6379
With above yaml files, I install helm chart named test.
After installing, the result of kubectl get svc,po,deploy,configmap is like this.
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.100.0.1 <none> 443/TCP 4d4h
service/user-service ClusterIP 10.100.88.0 <none> 50051/TCP 6s
service/redis ClusterIP 10.100.77.0 <none> 6379/TCP 6s
NAME READY STATUS RESTARTS AGE
pod/user-service-78548d4d8f-psbr2 0/1 ContainerCreating 0 6s
pod/redis 0/1 ContainerCreating 0 6s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/user-service 0/1 1 0 6s
NAME DATA AGE
configmap/kube-root-ca.crt 1 4d4h
configmap/redis-config 1 6s
But, when I checked the user-service's deploy logs, these error was occurred.
[Nest] 1 - 02/07/2023, 7:15:32 AM ERROR [TypeOrmModule] Unable to connect to the database. Retrying (1)...
Error: connect ECONNREFUSED 127.0.0.1:6379
at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1494:16)
I also checked through the console log that the REDIS_HOST environment variable is 10.100.77.0 in the database config of user-service, but an error was appearing while referring to the local host as above.
Is there any error in the part I set?

Answer 1

you can use service for connect to Redis. for this use redis.redis as REDIS_HOST in your application.