MaxScale Pod CrashLoopBackOff - Service Name Conflict

[achar007]

---

Hi folks,

I’m running MaxScale as a Kubernetes pod using a ConfigMap, Secret, and Service resources. However, I’m experiencing an issue where the MaxScale pod is in a CrashLoopBackOff state.

Here’s the command I used to apply the configuration:

kubectl apply -f maxscale.yaml

Below is the configuration from maxscale.yaml:

# maxscale.yaml
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: maxscale-config
data:
  maxscale.cnf: |
    ########################
    ## Server list
    ########################

    [server1]
    type            = server
    address         = mariadb-sts-0.mariadb-service.kaizen.svc.cluster.local
    port            = 3306
    protocol        = MariaDBBackend
    serv_weight     = 1

    [server2]
    type            = server
    address         = mariadb-sts-1.mariadb-service.kaizen.svc.cluster.local
    port            = 3306
    protocol        = MariaDBBackend
    serv_weight     = 1

    [server3]
    type            = server
    address         = mariadb-sts-2.mariadb-service.kaizen.svc.cluster.local
    port            = 3306
    protocol        = MariaDBBackend
    serv_weight     = 1

    #########################
    ## MaxScale configuration
    #########################

    [maxscale]
    threads                 = auto
    log_augmentation        = 1
    ms_timestamp            = 1
    syslog                  = 1

    #########################
    # Monitor for the servers
    #########################

    [MariaDB-Monitor]
    type                    = monitor
    module                  = mariadbmon
    servers                 = server1,server2,server3
    user                    = root
    password                = secret
    auto_failover           = true
    auto_rejoin             = true
    enforce_read_only_slaves = 1

    #########################
    ## Service definitions for read/write splitting and read-only services.
    #########################

    [Read-Write-Service]
    type            = service
    router          = readwritesplit
    servers         = server1,server2,server3
    user            = root
    password        = secret
    max_slave_connections           = 100%
    max_sescmd_history              = 1500
    causal_reads                    = true
    causal_reads_timeout            = 10
    transaction_replay              = true
    transaction_replay_max_size     = 1Mi
    delayed_retry                   = true
    master_reconnection             = true
    master_failure_mode             = fail_on_write
    max_slave_replication_lag       = 3

    [Read-Only-Service]
    type            = service
    router          = readconnroute
    servers         = server1,server2,server3
    router_options  = slave
    user            = root
    password        = secret

    ##########################
    ## Listener definitions for the service
    ## Listeners represent the ports the service will listen on.
    ##########################

    [Read-Write-Listener]
    type            = listener
    service         = Read-Write-Service
    protocol        = MariaDBClient
    port            = 4008

    [Read-Only-Listener]
    type            = listener
    service         = Read-Only-Service
    protocol        = MariaDBClient
    port            = 4006

---
apiVersion: v1
kind: Secret
metadata:
  name: maxscale-secret
type: Opaque
data:
  ROOT_USER: cm9vdA==  # "root" in base64
  ROOT_PASSWORD: c2VjcmV0  # "secret" in base64
  MAXSCALE_USER: cm9vdA==  # "root" in base64
  MAXSCALE_PASSWORD: c2VjcmV0  # "secret" in base64

---
apiVersion: v1
kind: Pod
metadata:
  name: maxscale
  labels:
    app: maxscale
spec:
  containers:
    - name: maxscale
      image: mariadb/maxscale:latest
      ports:
        - containerPort: 4006
        - containerPort: 4008
      volumeMounts:
        - name: maxscale-config
          mountPath: /etc/maxscale.cnf
          subPath: maxscale.cnf
      env:
        - name: ROOT_USER
          valueFrom:
            secretKeyRef:
              name: maxscale-secret
              key: ROOT_USER
        - name: ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: maxscale-secret
              key: ROOT_PASSWORD
        - name: MAXSCALE_USER
          valueFrom:
            secretKeyRef:
              name: maxscale-secret
              key: MAXSCALE_USER
        - name: MAXSCALE_PASSWORD
          valueFrom:
            secretKeyRef:
              name: maxscale-secret
              key: MAXSCALE_PASSWORD
  volumes:
    - name: maxscale-config
      configMap:
        name: maxscale-config

---
apiVersion: v1
kind: Service
metadata:
  name: maxscale-service
spec:
  type: ClusterIP
  ports:
    - port: 4006
      targetPort: 4006
      name: ro-listener
    - port: 4008
      targetPort: 4008
      name: rw-listener
  selector:
    app: maxscale

When I check the status of my pods with:

kubectl get all -n kaizen

I see the following output, indicating the MaxScale pod is failing:

NAME                READY   STATUS             RESTARTS      AGE
pod/mariadb-sts-0   1/1     Running            1 (78m ago)   95m
pod/mariadb-sts-1   1/1     Running            1 (78m ago)   131m
pod/mariadb-sts-2   1/1     Running            1 (78m ago)   130m
pod/maxscale        0/1     CrashLoopBackOff   1 (5s ago)    11s

NAME                       TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)             AGE
service/mariadb-service    ClusterIP   None            <none>        3306/TCP            132m
service/maxscale-service   ClusterIP   10.105.33.116   <none>        4006/TCP,4008/TCP   11s

NAME                           READY   AGE
statefulset.apps/mariadb-sts   3/3     132m

When I check the logs for the MaxScale pod, I see the following error message:

kubectl -n kaizen logs maxscale

Starting...
MaxScale PID = 18
'check system' not defined in control file, failed to add automatic configuration (service name maxscale is used already) -- please add 'check system <name>' manually
maxscale:2: Service name conflict, maxscale already defined '/var/log/monit.log'

Can anyone help me understand why the MaxScale pod is crashing and how to resolve this service name conflict? Any guidance would be greatly appreciated!

Thanks!