FAQ — PostgreSQL

What is the difference between resourcesPreset and resources?

The resourcesPreset field lets you choose a predetermined resource profile for each PostgreSQL replica. If the resources field (explicit CPU/memory) is defined, resourcesPreset is completely ignored.

Preset	CPU	Memory
nano	250m	128Mi
micro	500m	256Mi
small	1	512Mi
medium	1	1Gi
large	2	2Gi
xlarge	4	4Gi
2xlarge	8	8Gi

postgresql.yaml

spec:
  # Using a preset
  resourcesPreset: medium

  # OR explicit configuration (the preset is then ignored)
  resources:
    cpu: 2000m
    memory: 2Gi

How to choose between local and replicated storageClass?

Hikube offers two types of storage classes:

• local: data is stored on the physical node where the pod runs. This mode offers the best performance (minimal latency) but does not protect against node failure.
• replicated: data is replicated across multiple physical nodes. This mode ensures multi-DC high availability and protects against node loss, at the cost of slightly higher latency.

tip

Use storageClass: local if you configure multiple replicas (replicas > 1): application-level replication (PostgreSQL standby) already ensures high availability. Use storageClass: replicated if you have a single replica (replicas = 1): replicated storage compensates for the lack of application replication. In development with a single replica, local may be sufficient if data loss is acceptable.

How to connect to PostgreSQL from within the cluster?

The PostgreSQL service is accessible via the following Kubernetes service name:

• Read-write service: pg-<name>-rw on port 5432

Connection credentials are stored in a Kubernetes Secret named pg-<name>-app.

# Get the password
kubectl get tenantsecret pg-mydb-app -o jsonpath='{.data.password}' | base64 -d

# Get the username
kubectl get tenantsecret pg-mydb-app -o jsonpath='{.data.username}' | base64 -d

# Connect from a pod
psql -h pg-mydb-rw -p 5432 -U <username> -d <database>

How to configure synchronous replication?

Synchronous replication ensures that a transaction is only confirmed when it has been written to a minimum number of replicas. Configure the quorum parameters in your manifest:

postgresql.yaml

spec:
  replicas: 3
  quorum:
    minSyncReplicas: 1    # At least 1 replica must acknowledge
    maxSyncReplicas: 2    # At most 2 replicas acknowledge

• minSyncReplicas: minimum number of synchronous replicas that must acknowledge a transaction.
• maxSyncReplicas: maximum number of synchronous replicas that can acknowledge.

warning

Synchronous replication increases write latency. Make sure you have enough replicas (replicas >= maxSyncReplicas + 1).

How to enable PITR backup?

PostgreSQL on Hikube uses CloudNativePG with WAL archiving to enable Point-In-Time Recovery (PITR). Configure the backup section with S3-compatible storage:

postgresql.yaml

spec:
  backup:
    enabled: true
    schedule: "0 2 * * *"
    retentionPolicy: 30d
    destinationPath: s3://my-bucket/postgresql-backups/
    endpointURL: https://prod.s3.hikube.cloud
    s3AccessKey: your-access-key
    s3SecretKey: your-secret-key

Backups automatically include WAL files, which allows restoring the database to any point in time between two backups.

How to add PostgreSQL extensions?

You can enable PostgreSQL extensions for each database using the databases[name].extensions field:

postgresql.yaml

spec:
  databases:
    myapp:
      extensions:
        - uuid-ossp
        - pgcrypto
        - hstore
      roles:
        admin:
          - admin

Extensions are automatically enabled when the database is created. Available extensions depend on the deployed PostgreSQL version.

Can I create multiple databases and users?

Yes. Use the users and databases maps to define as many users and databases as needed. Each database can have distinct admin and readonly roles:

postgresql.yaml

spec:
  users:
    admin:
      password: AdminPassword123
      replication: true
    appuser:
      password: AppPassword456
    analyst:
      password: AnalystPassword789

  databases:
    production:
      roles:
        admin:
          - admin
        readonly:
          - analyst
      extensions:
        - uuid-ossp
    analytics:
      roles:
        admin:
          - admin
        readonly:
          - appuser
          - analyst