cozystack/packages/apps/postgres/README.md

Managed PostgreSQL Service

PostgreSQL is currently the leading choice among relational databases, known for its robust features and performance. The Managed PostgreSQL Service takes advantage of platform-side implementation to provide a self-healing replicated cluster. This cluster is efficiently managed using the highly acclaimed CloudNativePG operator, which has gained popularity within the community.

Deployment Details

This managed service is controlled by the CloudNativePG operator, ensuring efficient management and seamless operation.

• Docs: https://cloudnative-pg.io/docs/
• Github: https://github.com/cloudnative-pg/cloudnative-pg

Operations

How to enable backups

To back up a PostgreSQL application, an external S3-compatible storage is required.

To start regular backups, update the application, setting backup.enabled to true, and fill in the path and credentials to an backup.*:

## @param backup.enabled Enable regular backups
## @param backup.schedule Cron schedule for automated backups
## @param backup.retentionPolicy Retention policy
## @param backup.destinationPath Path to store the backup (i.e. s3://bucket/path/to/folder)
## @param backup.endpointURL S3 Endpoint used to upload data to the cloud
## @param backup.s3AccessKey Access key for S3, used for authentication
## @param backup.s3SecretKey Secret key for S3, used for authentication
backup:
  enabled: false
  retentionPolicy: 30d
  destinationPath: s3://bucket/path/to/folder/
  endpointURL: http://minio-gateway-service:9000
  schedule: "0 2 * * * *"
  s3AccessKey: oobaiRus9pah8PhohL1ThaeTa4UVa7gu
  s3SecretKey: ju3eum4dekeich9ahM1te8waeGai0oog

How to recover a backup

CloudNativePG supports point-in-time-recovery. Recovering a backup is done by creating a new database instance and restoring the data in it.

Create a new PostgreSQL application with a different name, but identical configuration. Set bootstrap.enabled to true and fill in the name of the database instance to recover from and the recovery time:

## @param bootstrap.enabled Restore database cluster from a backup
## @param bootstrap.recoveryTime Timestamp (PITR) up to which recovery will proceed, expressed in RFC 3339 format. If left empty, will restore latest
## @param bootstrap.oldName Name of database cluster before deleting
##
bootstrap:
  enabled: false
  recoveryTime: ""  # leave empty for latest or exact timestamp; example: 2020-11-26 15:22:00.00000+00
  oldName: "<previous-postgres-instance>"

How to switch primary/secondary replica

See:

• https://cloudnative-pg.io/documentation/1.15/rolling_update/#manual-updates-supervised

Parameters

Common parameters

Name	Description	Type	Value
external	Enable external access from outside the cluster	bool	false
size	Persistent Volume size	string	10Gi
replicas	Number of Postgres replicas	int	2
storageClass	StorageClass used to store the data	string	``
postgresql	PostgreSQL server configuration	object	null
postgresql.parameters	PostgreSQL server parameters	object
postgresql.parameters.max_connections	Determines the maximum number of concurrent connections to the database server. The default is typically 100 connections	int
quorum	Quorum configuration for synchronous replication	object	null
quorum.minSyncReplicas	Minimum number of synchronous replicas that must acknowledge a transaction before it is considered committed.	int
quorum.maxSyncReplicas	Maximum number of synchronous replicas that can acknowledge a transaction (must be lower than the number of instances).	int

Configuration parameters

Name	Description	Type	Value
users	Users configuration	map[string]user	{}
users[name].password	Password for the user	*string
users[name].replication	Whether the user has replication privileges	*bool
databases	Databases configuration	map[string]database	{}
databases[name].roles	Roles for the database	object
databases[name].roles.admin	List of users with admin privileges	[]string
databases[name].roles.readonly	List of users with read-only privileges	[]string
databases[name].extensions	Extensions enabled for the database	[]string

Backup parameters

Name	Description	Type	Value
backup	Backup configuration	object	null
backup.enabled	Enable regular backups	bool
backup.schedule	Cron schedule for automated backups	string
backup.retentionPolicy	Retention policy	string
backup.destinationPath	Path to store the backup (i.e. s3://bucket/path/to/folder)	string
backup.endpointURL	S3 Endpoint used to upload data to the cloud	string
backup.s3AccessKey	Access key for S3, used for authentication	string
backup.s3SecretKey	Secret key for S3, used for authentication	string

Bootstrap parameters

Name	Description	Type	Value
bootstrap	Bootstrap configuration	object	null
bootstrap.enabled	Restore database cluster from a backup	bool
bootstrap.recoveryTime	Timestamp (PITR) up to which recovery will proceed, expressed in RFC 3339 format. If left empty, will restore latest	string
bootstrap.oldName	Name of database cluster before deleting	string
resources	Resources	object	{}
resources.cpu	CPU	*quantity
resources.memory	Memory	*quantity
resourcesPreset	Default sizing preset used when resources is omitted.	string	micro

Parameter examples and reference

resources and resourcesPreset

resources sets explicit CPU and memory configurations for each replica. When left empty, the preset defined in resourcesPreset is applied.

resources:
  cpu: 4000m
  memory: 4Gi

resourcesPreset sets named CPU and memory configurations for each replica. This setting is ignored if the corresponding resources value is set.

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

users

users:
  user1:
    password: strongpassword
  user2:
    password: hackme
  airflow:
    password: qwerty123
  debezium:
    replication: true

databases

databases:          
  myapp:            
    roles:          
      admin:        
      - user1       
      - debezium    
      readonly:     
      - user2       
  airflow:          
    roles:          
      admin:        
      - airflow     
    extensions:     
    - hstore