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In this page, we have laid out the steps to upgrade postgres using pg_dump and pg_restore
This is a generic document, which you can use to upgrade from any version of postgres to any other version
We also talk a bit about Azure postgres and some ways to ensure your services dont update the database during upgrade
This upgrade procedures requires a downtime

Sl No

Task

Command

Comments

0

Create a new postgres instance

Choose postgres version 10 (preferably 11 ) and above and same configuration as per existing instance on Azure

You are free to have independent instances or a single instance for all services as per your need

Whitelist all the IP's as per existing postgres

Test the connection by connecting to the instance from jenkins

If on VM, create a new VM (preferably Ubuntu 18 and above) and run the Postgres provision role.

Note: This document does not cover details on how to upgrade postgres on the same / exisiting VM. Feel free to contribute the steps to this document.

New instance of same configuration should be created. We have used Postgres version 11

1

Update the inventory

Search and update all the variables in common.yml, secrets.yml Core and DataPipeline directory in private repository

Replace the postgres instance address, postgres user and postgres password with the new details

Also look at variable druid_postgres_user in case you are using Azure postgres. If you are using a common username and password per instance, then this variable needs to be added and the value should be your instance username. This variable will default to druid@instance

If you are on a VM, use the new VM IP along with username and password

It will be simpler if you use same username and password for all dbs on the postgres instance.

If you want to use different user name and password for each database on an instance, then you need to ensure you create those users and roles before hand by running provision jobs against your postgres instance or do them manually.

This document does not cover how to restore user accounts. For that you can refer to Azure docs or postgres documentation. Below is one such link -

https://docs.microsoft.com/en-us/azure/postgresql/how-to-upgrade-using-dump-and-restore

2

Start of down time

Stop traffic / services

Stop traffic

Put Jenkins into maintenance mode so nobody can deploy any jobs

Cut off connection to postgres from all services except Jenkins (In azure remove all connecting subnets except Jenkins, disable Azure services connections also)

In VM you have multiple ways - Disable outside connections by editing pg_hba.conf so only localhost connections are accepted. Or stop the below services so that they dont update postgres database

List of services that are going to be affected on Sunbird -

Code Block

language	yaml

- Deploy/DataPipeline/AnalyticsCore
- Deploy/DataPipeline/CoreDataProducts
- Deploy/DataPipeline/EdDataProducts
- Deploy/DataPipeline/FlinkPipelineJobs
- Deploy/Datapipeline/InternalKong
- Deploy/Kubernetes/Analytics
- Deploy/Kubernetes/APIManager
- Deploy/Kubernetes/Enc
- Deploy/Kubernetes/HawkeyeSuperset
- Deploy/Kubernetes/Keycloak
- Deploy/Kubernetes/Learner
- Deploy/Kubernetes/LMS
- Deploy/Kubernetes/Report
- Deploy/UCI/fusionauth
- Deploy/UCI/gql
- Deploy/UCI/Inbound
- Deploy/UCI/odk
- Deploy/UCI/Orchestrator
- Deploy/UCI/Outbound
- Deploy/UCI/Transformer
- Deploy/UCI/UCI
- DataPipeline/Druid
- Superset

List of services that are going to be affected on Vidyadaan -

Code Block

- Deploy/Kubernetes/APIManager
- Deploy/Kubernetes/Enc
- Deploy/Kubernetes/Opensaber
- Deploy/Kubernetes/Program
- Deploy/Kubernetes/HawkeyeSuperset
- Deploy/Kubernetes/PostgresqlMigration
- Deploy/DataPipeline/EdDataProducts

Respective services should be stopped / Postgres reachability should be removed

Traffic can be stopped based on situation by removing nginx daemonset or changing nginx service port mapping to something else from 80 / 443

3

Manually list all the DB's first

Code Block

language	bash

export PG_HOST="" # Enter the postgres host inside the quotes
export PG_USER="" # Enter the postgres user inside the quotes
export PGPASSWORD="" # Enter the postgres password inside the quotes

psql -h $PG_HOST -U $PG_USER -d postgres -c "\l"

All DB should be listed

4

Run command to get all the DB's on terminal and store in a file

Code Block

language	bash

mkdir $PG_HOST-$(date +'%s') && cd $PG_HOST-$(date +'%s')

psql -h $PG_HOST -U $PG_USER -d postgres -c "\l" | awk 'NR>3{print $1}'| grep -v "|\|(\|^$\|template0\|template1\|azure_maintenance\|postgres\|azure_sys" | tee -a dbs.txt

Verify all db are present in the file and matches our db's
Ignore db's like postgres, template0, template1, azure_maintanance and also remove not required DB's from the file

5

Take backup of the DB's from current instance

Code Block
while read -r line; do echo "Dumping DB $line" && pg_dump -Fd -j PG_CPU_CORES -h $PG_HOST -U $PG_USER -d $line -f $line; done < dbs.txt

Replace PG_CPU_CORES with the number of cores of the postgres insatnce.
Example: For 4 core, value will be 4

6

Get count of all tables from all DB's from current instance

Code Block

while read -r line; do psql -h $PG_HOST -U $PG_USER -d $line -c "\dt" | awk -F "|" 'NF {print $2}' | tr -d ' ' | awk 'NF' | tail -n +2 | tee -a $line-tables.txt; done < dbs.txt

while read -r line; do while read -r inline; do echo $inline | tee -a $line-table-count.txt  && psql -h $PG_HOST -U $PG_USER -d $line -c "SELECT COUNT(*) FROM \"$inline\"" | tee -a $line-table-count.txt; done < $line-tables.txt; done < dbs.txt

All tables and counts will be displayed and also written into the files

Repeat Steps 3 - 6 for every postgres instance (in case you are running the workload on separate instances)

7

Rearrange the DBs across two instances or based on your requirement

In this case, we will be creating the following databases across two instances

Instance 1 - Keycloak, Public Kong, Private Kong, Quartz, Enc Keys
Instance 2 - Analytics, Druid, Graphite

Feel free to add any other dbs you have / want to. This is not an exhaustive list

Create two directories as below

Code Block

language	bash

mkdir pg11
mkdir pg11-dp
cd pg11
touch dbs.txt

Add the required db names in the file dbs.txt. See next column for sample reference

Move all the required backup folders and files to this directory. Below is a sample command

Code Block
mv old_pg_backup_folder/api_manager_kong14* pg11

Similarly do for the other dbs and pg11-db folder also (second instance)

Code Block
cd pg11-dp touch dbs.txt

Add the required db names in the file dbs.txt. See next column for sample reference

If you are going to use only once instance, then you can move all the backup data and other files under a single directory

Instance 1:

Code Block

language	bash

cat pg11/dbs.txt 
api_manager_kong14
keycloak7
quartz
api_manager_internal
dev-keys

ls -lrth pg11
api_manager_internal
api_manager_internal-table-count.txt
api_manager_internal-tables.txt
api_manager_kong14
api_manager_kong14-table-count.txt
api_manager_kong14-tables.txt
keycloak7
keycloak7-table-count.txt
keycloak7-tables.txt
dev-keys
dev-keys-table-count.txt
dev-keys-tables.txt
quartz
quartz-table-count.txt
quartz-tables.txt
dbs.txt

Instance 2:

Code Block

cat pg11-dp/dbs.txt 
analytics
druid-raw
graphite
superset

ls -lrth pg11-dp
analytics
analytics-table-count.txt
analytics-tables.txt
druid-raw
druid-raw-table-count.txt
druid-raw-tables.txt
graphite
graphite-table-count.txt
graphite-tables.txt
superset
superset-tables.txt
dbs.txt

8

Install postgres 11 tools

Code Block
sudo apt install postgresql-client-11

If you to use pg_dump and pg_restore on older postgres version, install those packages

sudo apt install postgresql-client-9.6

9

Create empty databases in new instance

Code Block

language	bash

export PG_HOST="" # Enter the new postgres host inside the quotes
export PG_USER="" # Enter the new postgres user inside the quotes
export PGPASSWORD="" # Enter the new postgres password inside the quotes
psql -h $PG_HOST -U $PG_USER -d postgres -c "\l"

while read -r line; do echo "Creating DB $line" && psql -h $PG_HOST -U $PG_USER -d postgres -c "CREATE DATABASE $line"; done < dbs.txt
 
psql -h $PG_HOST -U $PG_USER -d postgres -c "\l"

Empty databases should be created on new postgres instance

Note: Add double quotes in dbs.txt if you have hyphen in DB name "DB-NAME" or else you will receive below error

Code Block
Creating DB loadtest-keys ERROR: syntax error at or near "-" LINE 1: CREATE DATABASE loadtest-keys

10

Restore the DB's to the new instance

Code Block
while read -r line; do echo "Restoring DB $line" && pg_restore -O -j PG_CPU_CORES -h $PG_HOST -U $PG_USER -d $line $line; done < dbs.txt

Replace PG_CPU_CORES with the number of cores of the postgres insatnce.
Example: For 4 core, value will be 4

Note: Remove double quotes in dbs.txt if you have hyphen in DB name "DB-NAME" or else you will receive below error

Code Block
Restoring DB "uci-botdb" pg_restore: [archiver] could not open input file ""uci-botdb"": No such file or directory

Ignore errors like

Code Block

ERROR: role "postgres" does not exist 

pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 5; 2615 2200 SCHEMA public azure_superuser
pg_restore: [archiver (db)] could not execute query: ERROR:  schema "public" already exists
    Command was: CREATE SCHEMA public;
    
pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 3728; 0 0 ACL SCHEMA public azure_superuser
pg_restore: [archiver (db)] could not execute query: ERROR:  role "postgres" does not exist
    Command was: GRANT ALL ON SCHEMA public TO postgres;

11

Analyze the db's on new instance

Code Block
while read -r line; do psql -h $PG_HOST -U $PG_USER -d $line -c "ANALYZE VERBOSE"; done < dbs.txt

Verbose logs will be displayed

12

Get count of all tables from all DB's from new instance

Code Block

while read -r line; do while read -r inline; do echo $inline | tee -a $line-table-count-new.txt  && psql -h $PG_HOST -U $PG_USER -d $line -c "SELECT COUNT(*) FROM \"$inline\"" | tee -a $line-table-count-new.txt; done < $line-tables.txt; done < dbs.txt

All tables and counts will be displayed and also written into the files

13

Compare the row counts of both the instances

Code Block
while read -r line; do echo "Diff of $line-table-count.txt and $line-table-count-new.txt" && diff $line-table-count.txt $line-table-count-new.txt; done < dbs.txt

This will not display any output. Which means files are identical

If there are differences use the below to compare and then take fresh backup and restore those dbs again
diff -y file1 file2

14

Remove all connections to old Postgres

Remove all subnets and enable deny public network acces on Azure portal

If on VM, stop the VM / postgres service

In case of Azure, make sure you update the Backup and Log retention days to a large number

To ensure no service can connect to old DBs

15

Clear offline session from Keycloak DB on Sunbird

Code Block
truncate offline_client_session; truncate offline_user_session;

If we have too many rows in these tables, keycloak will not start

16

End of down time Redeploy services / Enable Traffic

Redeploy the following services in case of Sunbird:

Code Block

language	yaml

- Deploy/DataPipeline/AnalyticsCore
- Deploy/DataPipeline/CoreDataProducts
- Deploy/DataPipeline/EdDataProducts
- Deploy/DataPipeline/FlinkPipelineJobs (Choose all in job_names_to_deploy)
- Deploy/Datapipeline/InternalKong
- Deploy/Kubernetes/Analytics
- Deploy/Kubernetes/APIManager
- Deploy/Kubernetes/Enc
- Deploy/Kubernetes/HawkeyeSuperset
- Deploy/Kubernetes/Keycloak
- Deploy/Kubernetes/Learner
- Deploy/Kubernetes/LMS
- Deploy/Kubernetes/Report
- Deploy/UCI/fusionauth
- Deploy/UCI/gql
- Deploy/UCI/Inbound
- Deploy/UCI/odk
- Deploy/UCI/Orchestrator
- Deploy/UCI/Outbound
- Deploy/UCI/Transformer
- Deploy/UCI/UCI
- Provision/DataPipeline/Druid (Choose all in service except java)
- Superset - No Jenkins Job

Redeploy the following services in case of Vidyadaan:

Code Block

- Deploy/Kubernetes/APIManager
- Deploy/Kubernetes/Enc
- Deploy/Kubernetes/Opensaber
- Deploy/Kubernetes/Program
- Deploy/Kubernetes/HawkeyeSuperset
- Deploy/Kubernetes/PostgresqlMigration
- Deploy/DataPipeline/EdDataProducts

The configmaps and configuration files will be updated with new data. Do verify it by checking them manually for all these services.

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