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I want to create a shell script which automates the creation and running and creating database in a postgres database using docker.
I want to use the docker postgres official package for postgres in docker.
The script that I use is as follows:
docker network create --subnet=172.18.0.0/16 shared_network;
docker kill postgres_linker;
docker rm postgres_linker;
docker run --name postgres_linker -e POSTGRES_PASSWORD=blahblahblah -d --net shared_network --ip 172.18.0.2 postgres:10-alpine;
docker exec -it postgres_linker psql -U postgres -c "create database linker;";
But when I run this I get the following output without any database being created:
Error response from daemon: network with name shared_network already exists
postgres_linker
postgres_linker
b2a9fd4d6e25b62d60adb05c8b6b653a1b55ec7a869c4728677d6289f5cddd63
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
The first line of this log is OK, the second and third are too, The problem is that psql does not run the command on the postgres container althogh the command I am trying to run is correct. If I run the last command seperately from my shell script:
docker exec -it postgres_linker psql -U postgres -c "create database linker;";
It does not give me error! and it works!
Why is this behavior happening?
I found the solution to my problem.
Unfortunately I thought that when postgres container is run the server is up and running immediately.
It was not true and it takes some time to come up. so I have needed to add some delay.
So the resulting script file should look like this:
docker network create --subnet=172.18.0.0/16 shared_network;
docker kill postgres_linker;
docker rm postgres_linker;
docker run --name postgres_linker -e POSTGRES_PASSWORD=blahblahblah -d --net shared_network --ip 172.18.0.2 postgres:10-alpine;
sleep 5;
docker exec -it postgres_linker psql -U postgres -c "create database linker;";
I'm working with docker to test a web application, and this application needs a database. I copied my application in a tomcat container and created a mssql container.
However, I need to copy my mssql database located in a server called "tstsupsq" with all datas (not only the schema) in my mssql container.
PS : I don't have access to mdf files of the tstsupsq server
Do someone can help me ?
Thanks
EDIT :
After many tries, I fixed this issue with command lines.
How to copy mssql database from any server to docker with command lines :
sqlcmd.exe -S myServer -U myUser -P myPassword -Q "BACKUP DATABASE [databaseName] TO DISK='backupLocation\databaseName.bak'"
docker run -d -p 1433:1433 -e ACCEPT_EULA=Y -e SA_PASSWORD=myPassword --name containerName microsoft/mssql-server-linux:latest
docker cp backupLocation\databaseName.bak containerName:/var/opt/mssql/data
docker exec -it containerName /opt/mssql-tools/bin/sqlcmd -S localhost -U sa -P myPassword -Q "RESTORE DATABASE [databaseName] FROM DISK='/var/opt/mssql/data\databaseName.bak' WITH MOVE 'databaseName' TO '/var/opt/mssql/data/databaseName.mdf', MOVE 'databaseName_Log' TO '/var/opt/mssql/data/databaseName.ldf'"
Your database is now avaible with all its datas in your docker container.
Use cp command to copy your bak file to container
docker cp YourDbBackup.bak YourContainer:/YourDbBackup.bak
Then use SSMS to restore bak file.
I'm looking to copy a production PostgreSQL database to a development server. What's the quickest, easiest way to go about doing this?
You don't need to create an intermediate file. You can do
pg_dump -C -h localhost -U localuser dbname | psql -h remotehost -U remoteuser dbname
or
pg_dump -C -h remotehost -U remoteuser dbname | psql -h localhost -U localuser dbname
using psql or pg_dump to connect to a remote host.
With a big database or a slow connection, dumping a file and transfering the file compressed may be faster.
As Kornel said there is no need to dump to a intermediate file, if you want to work compressed you can use a compressed tunnel
pg_dump -C dbname | bzip2 | ssh remoteuser#remotehost "bunzip2 | psql dbname"
or
pg_dump -C dbname | ssh -C remoteuser#remotehost "psql dbname"
but this solution also requires to get a session in both ends.
Note: pg_dump is for backing up and psql is for restoring. So, the first command in this answer is to copy from local to remote and the second one is from remote to local. More -> https://www.postgresql.org/docs/9.6/app-pgdump.html
pg_dump the_db_name > the_backup.sql
Then copy the backup to your development server, restore with:
psql the_new_dev_db < the_backup.sql
Use pg_dump, and later psql or pg_restore - depending whether you choose -Fp or -Fc options to pg_dump.
Example of usage:
ssh production
pg_dump -C -Fp -f dump.sql -U postgres some_database_name
scp dump.sql development:
rm dump.sql
ssh development
psql -U postgres -f dump.sql
If you are looking to migrate between versions (eg you updated postgres and have 9.1 running on localhost:5432 and 9.3 running on localhost:5434) you can run:
pg_dumpall -p 5432 -U myuser91 | psql -U myuser94 -d postgres -p 5434
Check out the migration docs.
pg_basebackup seems to be the better way of doing this now, especially for large databases.
You can copy a database from a server with the same or older major version. Or more precisely:
pg_basebackup works with servers of the same or an older major version, down to 9.1. However, WAL streaming mode (-X stream) only works with server version 9.3 and later, and tar format mode (--format=tar) of the current version only works with server version 9.5 or later.
For that you need on the source server:
listen_addresses = '*' to be able to connect from the target server. Make sure port 5432 is open for that matter.
At least 1 available replication connection: max_wal_senders = 1 (-X fetch), 2 for -X stream (the default in case of PostgreSQL 12), or more.
wal_level = replica or higher to be able to set max_wal_senders > 0.
host replication postgres DST_IP/32 trust in pg_hba.conf. This grants access to the pg cluster to anyone from the DST_IP machine. You might want to resort to a more secure option.
Changes 1, 2, 3 require server restart, change 4 requires reload.
On the target server:
# systemctl stop postgresql#VERSION-NAME
postgres$ pg_basebackup -h SRC_IP -U postgres -D VERSION/NAME --progress
# systemctl start postgresql#VERSION-NAME
Accepted answer is correct, but if you want to avoid entering the password interactively, you can use this:
PGPASSWORD={{export_db_password}} pg_dump --create -h {{export_db_host}} -U {{export_db_user}} {{export_db_name}} | PGPASSWORD={{import_db_password}} psql -h {{import_db_host}} -U {{import_db_user}} {{import_db_name}}
Run this command with database name, you want to backup, to take dump of DB.
pg_dump -U {user-name} {source_db} -f {dumpfilename.sql}
eg. pg_dump -U postgres mydbname -f mydbnamedump.sql
Now scp this dump file to remote machine where you want to copy DB.
eg. scp mydbnamedump.sql user01#remotemachineip:~/some/folder/
On remote machine run following command in ~/some/folder to restore the DB.
psql -U {user-name} -d {desintation_db}-f {dumpfilename.sql}
eg. psql -U postgres -d mynewdb -f mydbnamedump.sql
Dump your database : pg_dump database_name_name > backup.sql
Import your database back: psql db_name < backup.sql
I struggled quite a lot and eventually the method that allowed me to make it work with Rails 4 was:
on your old server
sudo su - postgres
pg_dump -c --inserts old_db_name > dump.sql
I had to use the postgres linux user to create the dump. also i had to use -c to force the creation of the database on the new server. --inserts tells it to use the INSERT() syntax which otherwise would not work for me :(
then, on the new server, simpy:
sudo su - postgres
psql new_database_name < dump.sql
to transfer the dump.sql file between server I simply used the "cat" to print the content and than "nano" to recreate it copypasting the content.
Also, the ROLE i was using on the two database was different so i had to find-replace all the owner name in the dump.
Let me share a Linux shell script to copy your table data from one server to another PostgreSQL server.
Reference taken from this blog:
Linux Bash Shell Script for data migration between PostgreSQL Servers:
#!/bin/bash
psql \
-X \
-U user_name \
-h host_name1 \
-d database_name \
-c "\\copy tbl_Students to stdout" \
| \
psql \
-X \
-U user_name \
-h host_name2 \
-d database_name \
-c "\\copy tbl_Students from stdin"
I am just migrating the data; please create a blank table at your destination/second database server.
This is a utility script. Further, you can modify the script for generic use something like by adding parameters for host_name, database_name, table_name and others
Here is an example using pg_basebackup
I chose to go this route because it backs up the entire database cluster (users, databases, etc.).
I'm posting this as a solution on here because it details every step I had to take, feel free to add recommendations or improvements after reading other answers on here and doing some more research.
For Postgres 12 and Ubuntu 18.04 I had to do these actions:
On the server that is currently running the database:
Update pg_hba.conf, for me located at /etc/postgresql/12/main/pg_hba.conf
Add the following line (substitute 192.168.0.100 with the IP address of the server you want to copy the database to).
host replication postgres 192.168.0.100/32 trust
Update postgresql.conf, for me located at /etc/postgresql/12/main/postgresql.conf. Add the following line:
listen_addresses = '*'
Restart postgres:
sudo service postgresql restart
On the host you want to copy the database cluster to:
sudo service postgresql stop
sudo su root
rm -rf /var/lib/postgresql/12/main/*
exit
sudo -u postgres pg_basebackup -h 192.168.0.101 -U postgres -D /var/lib/postgresql/12/main/
sudo service postgresql start
Big picture - stop the service, delete everything in the data directory (mine is in /var/lib/postgreql/12). The permissions on this directory are drwx------ with user and group postgres. I could only do this as root, not even with sudo -u postgres. I'm unsure why. Ensure you are doing this on the new server you want to copy the database to! You are deleting the entire database cluster.
Make sure to change the IP address from 192.168.0.101 to the IP address you are copying the database from. Copy the data from the original server with pg_basebackup. Start the service.
Update pg_hba.conf and postgresql.conf to match the original server configuration - before you made any changes adding the replication line and the listen_addresses line (in my care I had to add the ability to log-in locally via md5 to pg_hba.conf).
Note there are considerations for max_wal_senders and wal_level that can be found in the documentation. I did not have to do anything with this.
If you are more comfortable with a GUI, you can use the pgAdmin software.
Connect to your source and destination servers
Right-click on the source db > backup
Right-click on the destination server > create > database. Use the same properties as the source db (you can see the properties of the source db by right-click > properties)
Right-click on the created db > restore.
I'm trying to backup/restore a PostgreSQL database as is explained on the Docker website, but the data is not restored.
The volumes used by the database image are:
VOLUME ["/etc/postgresql", "/var/log/postgresql", "/var/lib/postgresql"]
and the CMD is:
CMD ["/usr/lib/postgresql/9.3/bin/postgres", "-D", "/var/lib/postgresql/9.3/main", "-c", "config_file=/etc/postgresql/9.3/main/postgresql.conf"]
I create the DB container with this command:
docker run -it --name "$DB_CONTAINER_NAME" -d "$DB_IMAGE_NAME"
Then I connect another container to insert some data manually:
docker run -it --rm --link "$DB_CONTAINER_NAME":db "$DB_IMAGE_NAME" sh -c 'exec bash'
psql -d test -h $DB_PORT_5432_TCP_ADDR
# insert some data in the db
<CTRL-D>
<CTRL-D>
The tar archive is then created:
$ sudo docker run --volumes-from "$DB_CONTAINER_NAME" --rm -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /etc/postgresql /var/log/postgresql /var/lib/postgresql
Now I remove the container used for the db and create another one, with the same name, and try to restore the data inserted before:
$ sudo docker run --volumes-from "$DB_CONTAINER_NAME" --rm -v $(pwd):/backup ubuntu tar xvf /backup/backup.tar
But the tables are empty, why is the data not properly restored ?
Backup your databases
docker exec -t your-db-container pg_dumpall -c -U postgres > dump_`date +%d-%m-%Y"_"%H_%M_%S`.sql
Restore your databases
cat your_dump.sql | docker exec -i your-db-container psql -U postgres
Backup Database
generate sql:
docker exec -t your-db-container pg_dumpall -c -U your-db-user > dump_$(date +%Y-%m-%d_%H_%M_%S).sql
to reduce the size of the sql you can generate a compress:
docker exec -t your-db-container pg_dumpall -c -U your-db-user | gzip > ./dump_$(date +"%Y-%m-%d_%H_%M_%S").gz
Restore Database
cat your_dump.sql | docker exec -i your-db-container psql -U your-db-user -d your-db-name
to restore a compressed sql:
gunzip < your_dump.sql.gz | docker exec -i your-db-container psql -U your-db-user -d your-db-name
PD: this is a compilation of what worked for me, and what I got from here and elsewhere. I am beginning to make contributions, any feedback will be appreciated.
I think you can also use a postgres backup container which would backup your databases within a given time duration.
pgbackups:
container_name: Backup
image: prodrigestivill/postgres-backup-local
restart: always
volumes:
- ./backup:/backups
links:
- db:db
depends_on:
- db
environment:
- POSTGRES_HOST=db
- POSTGRES_DB=${DB_NAME}
- POSTGRES_USER=${DB_USER}
- POSTGRES_PASSWORD=${DB_PASSWORD}
- POSTGRES_EXTRA_OPTS=-Z9 --schema=public --blobs
- SCHEDULE=#every 0h30m00s
- BACKUP_KEEP_DAYS=7
- BACKUP_KEEP_WEEKS=4
- BACKUP_KEEP_MONTHS=6
- HEALTHCHECK_PORT=81
cat db.dump | docker exec ... way didn't work for my dump (~2Gb). It took few hours and ended up with out-of-memory error.
Instead, I cp'ed dump into container and pg_restore'ed it from within.
Assuming that container id is CONTAINER_ID and db name is DB_NAME:
# copy dump into container
docker cp local/path/to/db.dump CONTAINER_ID:/db.dump
# shell into container
docker exec -it CONTAINER_ID bash
# restore it from within
pg_restore -U postgres -d DB_NAME --no-owner -1 /db.dump
Okay, I've figured this out. Postgresql does not detect changes to the folder /var/lib/postgresql once it's launched, at least not the kind of changes I want it do detect.
The first solution is to start a container with bash instead of starting the postgres server directly, restore the data, and then start the server manually.
The second solution is to use a data container. I didn't get the point of it before, now I do.
This data container allows to restore the data before starting the postgres container. Thus, when the postgres server starts, the data are already there.
The below command can be used to take dump from docker postgress container
docker exec -t <postgres-container-name> pg_dump --no-owner -U <db-username> <db-name> > file-name-to-backup-to.sql
The top answer didn't work for me. I kept getting this error:
psql: error: FATAL: Peer authentication failed for user "postgres"
To get it to work I had to specify a user for the docker container:
Backup
docker exec -t --user postgres your-db-container pg_dumpall -c -U postgres > dump_`date +%d-%m-%Y"_"%H_%M_%S`.sql
Restore
cat your_dump.sql | docker exec -i --user postgres your-db-container psql -U postgres
Another approach (based on docker-postgresql-workflow)
Local running database (not in docker, but same approach would work) to export:
pg_dump -F c -h localhost mydb -U postgres export.dmp
Container database to import:
docker run -d -v /local/path/to/postgres:/var/lib/postgresql/data postgres #ex runs container as `CONTAINERNAME` #find via `docker ps`
docker run -it --link CONTAINERNAME:postgres --volume $PWD/:/tmp/ postgres bash -c 'exec pg_restore -h postgres -U postgres -d mydb -F c /tmp/sonar.dmp'
I had this issue while trying to use a db_dump to restore a db. I normally use dbeaver to restore- however received a psql dump, so had to figure out a method to restore using the docker container.
The methodology recommended by Forth and edited by Soviut worked for me:
cat your_dump.sql | docker exec -i your-db-container psql -U postgres -d dbname
(since this was a single db dump and not multiple db's i included the name)
However, in order to get this to work, I had to also go into the virtualenv that the docker container and project were in. This eluded me for a bit before figuring it out- as I was receiving the following docker error.
read unix #->/var/run/docker.sock: read: connection reset by peer
This can be caused by the file /var/lib/docker/network/files/local-kv.db .I don't know the accuracy of this statement: but I believe I was seeing this as I do not user docker locally, so therefore did not have this file, which it was looking for, using Forth's answer.
I then navigated to correct directory (with the project) activated the virtualenv and then ran the accepted answer. Boom, worked like a top. Hope this helps someone else out there!
dksnap (https://github.com/kelda/dksnap) automates the process of running pg_dumpall and loading the dump via /docker-entrypoint-initdb.d.
It shows you a list of running containers, and you pick which one you want to backup. The resulting artifact is a regular Docker image, so you can then docker run it, or share it by pushing it to a Docker registry.
(disclaimer: I'm a maintainer on the project)
This is the command worked for me.
cat your_dump.sql | sudo docker exec -i {docker-postgres-container} psql -U {user} -d {database_name}
for example
cat table_backup.sql | docker exec -i 03b366004090 psql -U postgres -d postgres
Reference: Solution given by GMartinez-Sisti in this discussion.
https://gist.github.com/gilyes/525cc0f471aafae18c3857c27519fc4b
Solution for docker-compose users:
At First run the docker-compose file by any on of following commands: $ docker-compose -f loca.yml up OR docker-compose -f loca.yml up -d
For taking backup: $ docker-compose -f local.yml exec postgres backup
To see list of backups inside container: $ docker-compose -f local.yml exec postgres backups
Open another terminal and run following command: $ docker ps
Look for the CONTAINER ID of postgres image and copy the ID. Let's assume the CONTAINER ID is: ba78c0f9bcee
Now to bring that backup into your local file system, run the following command: $ docker cp ba78c0f9bcee:/backups ./local_backupfolder
Hope this will help someone who was lost just like me..
N.B: The full details of this solution can be found here.
Another way to do it is to run the pg_restore (of course if you have postgres set up in your host machine) command from the host machine.
Assuming that you have port mapping "5436:5432" for the postgres service in your docker-compose file. Having this port mapping will let you access the container's postgres (running on port 5432) via your host machine's port 5436
pg_restore -h localhost -p 5436 -U <POSTGRES_USER> -d <POSTGRES_DB> /Path/to/the/.psql/file/in/your/host_machine
This way you do not have to dive into the container's terminal or copy the dump file to the container.
I would like to add the official docker documentation for backups and restores. This applies to all kinds of data within a volume, not just postegres.
Backup a container
Create a new container named dbstore:
$ docker run -v /dbdata --name dbstore ubuntu /bin/bash
Then in the next command, we:
Launch a new container and mount the volume from the dbstore container
Mount a local host directory as /backup
Pass a command that tars the contents of the dbdata volume to a backup.tar file inside our /backup directory.
$ docker run --rm --volumes-from dbstore -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /dbdata
When the command completes and the container stops, we are left with a backup of our dbdata volume.
Restore container from backup
With the backup just created, you can restore it to the same container, or another that you made elsewhere.
For example, create a new container named dbstore2:
$ docker run -v /dbdata --name dbstore2 ubuntu /bin/bash
Then un-tar the backup file in the new container`s data volume:
$ docker run --rm --volumes-from dbstore2 -v $(pwd):/backup ubuntu bash -c "cd /dbdata && tar xvf /backup/backup.tar --strip 1"
You can use the techniques above to automate backup, migration and restore testing using your preferred tools.
Using a File System Level Backup on Docker Volumes
Example Docker Compose
version: "3.9"
services:
db:
container_name: pg_container
image: platerecognizer/parkpow-postgres
# restart: always
volumes:
- postgres_data:/var/lib/postgresql/data/
environment:
POSTGRES_USER: admin
POSTGRES_PASSWORD: admin
POSTGRES_DB: admin
volumes:
postgres_data:
Backup Postgresql Volume
docker run --rm \
--user root \
--volumes-from pg_container \
-v /tmp/db-bkp:/backup \
ubuntu tar cvf /backup/db.tar /var/lib/postgresql/data
Then copy /tmp/db-bkp to second host
Restore Postgresql Volume
docker run --rm \
--user root \
--volumes-from pg_container \
-v /tmp/db-bkp:/backup \
ubuntu bash -c "cd /var && tar xvf /backup/db.tar --strip 1"
I'm looking to copy a production PostgreSQL database to a development server. What's the quickest, easiest way to go about doing this?
You don't need to create an intermediate file. You can do
pg_dump -C -h localhost -U localuser dbname | psql -h remotehost -U remoteuser dbname
or
pg_dump -C -h remotehost -U remoteuser dbname | psql -h localhost -U localuser dbname
using psql or pg_dump to connect to a remote host.
With a big database or a slow connection, dumping a file and transfering the file compressed may be faster.
As Kornel said there is no need to dump to a intermediate file, if you want to work compressed you can use a compressed tunnel
pg_dump -C dbname | bzip2 | ssh remoteuser#remotehost "bunzip2 | psql dbname"
or
pg_dump -C dbname | ssh -C remoteuser#remotehost "psql dbname"
but this solution also requires to get a session in both ends.
Note: pg_dump is for backing up and psql is for restoring. So, the first command in this answer is to copy from local to remote and the second one is from remote to local. More -> https://www.postgresql.org/docs/9.6/app-pgdump.html
pg_dump the_db_name > the_backup.sql
Then copy the backup to your development server, restore with:
psql the_new_dev_db < the_backup.sql
Use pg_dump, and later psql or pg_restore - depending whether you choose -Fp or -Fc options to pg_dump.
Example of usage:
ssh production
pg_dump -C -Fp -f dump.sql -U postgres some_database_name
scp dump.sql development:
rm dump.sql
ssh development
psql -U postgres -f dump.sql
If you are looking to migrate between versions (eg you updated postgres and have 9.1 running on localhost:5432 and 9.3 running on localhost:5434) you can run:
pg_dumpall -p 5432 -U myuser91 | psql -U myuser94 -d postgres -p 5434
Check out the migration docs.
pg_basebackup seems to be the better way of doing this now, especially for large databases.
You can copy a database from a server with the same or older major version. Or more precisely:
pg_basebackup works with servers of the same or an older major version, down to 9.1. However, WAL streaming mode (-X stream) only works with server version 9.3 and later, and tar format mode (--format=tar) of the current version only works with server version 9.5 or later.
For that you need on the source server:
listen_addresses = '*' to be able to connect from the target server. Make sure port 5432 is open for that matter.
At least 1 available replication connection: max_wal_senders = 1 (-X fetch), 2 for -X stream (the default in case of PostgreSQL 12), or more.
wal_level = replica or higher to be able to set max_wal_senders > 0.
host replication postgres DST_IP/32 trust in pg_hba.conf. This grants access to the pg cluster to anyone from the DST_IP machine. You might want to resort to a more secure option.
Changes 1, 2, 3 require server restart, change 4 requires reload.
On the target server:
# systemctl stop postgresql#VERSION-NAME
postgres$ pg_basebackup -h SRC_IP -U postgres -D VERSION/NAME --progress
# systemctl start postgresql#VERSION-NAME
Accepted answer is correct, but if you want to avoid entering the password interactively, you can use this:
PGPASSWORD={{export_db_password}} pg_dump --create -h {{export_db_host}} -U {{export_db_user}} {{export_db_name}} | PGPASSWORD={{import_db_password}} psql -h {{import_db_host}} -U {{import_db_user}} {{import_db_name}}
Run this command with database name, you want to backup, to take dump of DB.
pg_dump -U {user-name} {source_db} -f {dumpfilename.sql}
eg. pg_dump -U postgres mydbname -f mydbnamedump.sql
Now scp this dump file to remote machine where you want to copy DB.
eg. scp mydbnamedump.sql user01#remotemachineip:~/some/folder/
On remote machine run following command in ~/some/folder to restore the DB.
psql -U {user-name} -d {desintation_db}-f {dumpfilename.sql}
eg. psql -U postgres -d mynewdb -f mydbnamedump.sql
Dump your database : pg_dump database_name_name > backup.sql
Import your database back: psql db_name < backup.sql
I struggled quite a lot and eventually the method that allowed me to make it work with Rails 4 was:
on your old server
sudo su - postgres
pg_dump -c --inserts old_db_name > dump.sql
I had to use the postgres linux user to create the dump. also i had to use -c to force the creation of the database on the new server. --inserts tells it to use the INSERT() syntax which otherwise would not work for me :(
then, on the new server, simpy:
sudo su - postgres
psql new_database_name < dump.sql
to transfer the dump.sql file between server I simply used the "cat" to print the content and than "nano" to recreate it copypasting the content.
Also, the ROLE i was using on the two database was different so i had to find-replace all the owner name in the dump.
Let me share a Linux shell script to copy your table data from one server to another PostgreSQL server.
Reference taken from this blog:
Linux Bash Shell Script for data migration between PostgreSQL Servers:
#!/bin/bash
psql \
-X \
-U user_name \
-h host_name1 \
-d database_name \
-c "\\copy tbl_Students to stdout" \
| \
psql \
-X \
-U user_name \
-h host_name2 \
-d database_name \
-c "\\copy tbl_Students from stdin"
I am just migrating the data; please create a blank table at your destination/second database server.
This is a utility script. Further, you can modify the script for generic use something like by adding parameters for host_name, database_name, table_name and others
Here is an example using pg_basebackup
I chose to go this route because it backs up the entire database cluster (users, databases, etc.).
I'm posting this as a solution on here because it details every step I had to take, feel free to add recommendations or improvements after reading other answers on here and doing some more research.
For Postgres 12 and Ubuntu 18.04 I had to do these actions:
On the server that is currently running the database:
Update pg_hba.conf, for me located at /etc/postgresql/12/main/pg_hba.conf
Add the following line (substitute 192.168.0.100 with the IP address of the server you want to copy the database to).
host replication postgres 192.168.0.100/32 trust
Update postgresql.conf, for me located at /etc/postgresql/12/main/postgresql.conf. Add the following line:
listen_addresses = '*'
Restart postgres:
sudo service postgresql restart
On the host you want to copy the database cluster to:
sudo service postgresql stop
sudo su root
rm -rf /var/lib/postgresql/12/main/*
exit
sudo -u postgres pg_basebackup -h 192.168.0.101 -U postgres -D /var/lib/postgresql/12/main/
sudo service postgresql start
Big picture - stop the service, delete everything in the data directory (mine is in /var/lib/postgreql/12). The permissions on this directory are drwx------ with user and group postgres. I could only do this as root, not even with sudo -u postgres. I'm unsure why. Ensure you are doing this on the new server you want to copy the database to! You are deleting the entire database cluster.
Make sure to change the IP address from 192.168.0.101 to the IP address you are copying the database from. Copy the data from the original server with pg_basebackup. Start the service.
Update pg_hba.conf and postgresql.conf to match the original server configuration - before you made any changes adding the replication line and the listen_addresses line (in my care I had to add the ability to log-in locally via md5 to pg_hba.conf).
Note there are considerations for max_wal_senders and wal_level that can be found in the documentation. I did not have to do anything with this.
If you are more comfortable with a GUI, you can use the pgAdmin software.
Connect to your source and destination servers
Right-click on the source db > backup
Right-click on the destination server > create > database. Use the same properties as the source db (you can see the properties of the source db by right-click > properties)
Right-click on the created db > restore.