Application-Consistent Protection for PostgreSQL on Kubernetes

You can add a pre-process script file or a post-process script file for PostgreSQL on the Kubernetes access nodes.

Example Pre-Process Script

The following example is a pre-process script for PostgreSQL. Edit the example script to include the PostgreSQL port, database user credentials, and the name of a database on the PostgreSQL server, other than the template0 database.

#!/usr/bin/env python

import psycopg2

import os, time, datetime

dt=datetime.datetime.now().strftime("%I:%M%p on %B %d, %Y")

file1 = open("/scripts/pre-freeze.log","a+" )

conn = None

exit_status = 0

try:

  conn = psycopg2.connect(host='localhost',port='<POSTGRESQL_PORT>',user='<POSTGRESQL_USER>',password='<POSTGRESQL_PASSWORD>',database='<POSTGRESQL_DB_NAME>')

  cur = conn.cursor()

  cur.execute ("select version();")

  data = cur.fetchone()

  file1.write (dt)

  file1.write ("\n-------------------------------------------\n")

  file1.write ("\t PostgreSQL version is %s: "%data)

  file1.write ("\n-------------------------------------------\n")

  file1.write (dt)

  file1.write ("\t executing query to quiesce the database \n")

  cur.execute (" select pg_start_backup('label'); ")

  file1.write (dt)

  file1.write ("\t Database is quiesced now successfully \n")

  cur.close()

except (Exception, psycopg2.DatabaseError) as error:

  file1.write(dt)

  file1.write(str(error))

  file1.write( "\n Error in quiesce DB, please check PostgreSQL logs for more info\n")

  exit_status = 1

finally:

  if conn is not None:

    conn.close()

    file1.write( "\n Database connection closed\n")

file1.close()

exit(exit_status)

Example Post-Process Script

The following example is a post-process script for PostgreSQL. Edit the example script to include the PostgreSQL port, database user credentials, and the name of a database on the PostgreSQL server, other than the template0 database.

import psycopg2

import os, time, datetime

dt=datetime.datetime.now().strftime("%I:%M%p on %B %d, %Y")

file1 = open("/scripts/post-thaw.log","a+" )

conn = None

exit_status = 0

try:

  conn = psycopg2.connect(host='localhost',port='<POSTGRESQL_PORT>',user='<POSTGRESQL_USER>',password='<POSTGRESQL_PASSWORD>',database='<POSTGRESQL_DB_NAME>')

  cur = conn.cursor()

  cur.execute ("select version();")

  data = cur.fetchone()

  file1.write (dt)

  file1.write ("\n-------------------------------------------\n")

  file1.write ("\t PostgreSQL version is %s: "%data)

  file1.write ("\n-------------------------------------------\n")

  file1.write (dt)

  file1.write ("\t executing query to unquiesce the database \n")

  cur.execute ("select pg_stop_backup();")

  file1.write (dt)

  file1.write ("\t Database is unquiesced now \n")

  cur.close()

except(Exception, psycopg2.DatabaseError) as error:

  file1.write(dt)

  file1.write(str(error))

  file1.write( "\n Error in unquiesce DB, please check PostgreSQL logs for more info \n")

  exit_status = 1

finally:

  if conn is not None:

    conn.close()

    file1.write( "\n Database connection closed\n")

file1.close()

exit(exit_status)

Output and Log Files

Output from the scripts is written to the following files on your production PostgreSQL pod:

• Pre-execution script: /scripts/pre-freeze.log

• Post-execution script: /scripts/pre-thaw.log

To modify the paths, edit the scripts that are stored on your access nodes.