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pgBackRest setup

pgBackRest is a backup tool used to perform PostgreSQL database backup, archiving, restoration, and point-in-time recovery. While it can be used for local backups, this procedure shows how to deploy a pgBackRest server running on a dedicated host and how to configure PostgreSQL servers to use it for backups and archiving.

You also need a backup storage to store the backups. It can either be a remote storage such as AWS S3, S3-compatible storages or Azure blob storage, or a filesystem-based one.

Configure backup server

To make things easier when working with some templates, run the commands below as the root user. Run the following command to switch to the root user:

$ sudo su -

Install pgBackRest

  1. Enable the repository with percona-release

    $ percona-release setup ppg-15       
    
  2. Install pgBackRest package

    $ apt install percona-pgbackrest
    
    $ yum install percona-pgbackrest
    

Create the configuration file

  1. Create environment variables to simplify the config file creation:

    export SRV_NAME="bkp-srv"
    export NODE1_NAME="node-1"
    export NODE2_NAME="node-2"
    export NODE3_NAME="node-3"
    export CA_PATH="/etc/ssl/certs/pg_ha"
    
  2. Create the pgBackRest repository, if necessary

    A repository is where pgBackRest stores backups. In this example, the backups will be saved to /var/lib/pgbackrest.

    This directory is usually created during pgBackRest’s installation process. If it’s not there already, create it as follows:

    $ mkdir -p /var/lib/pgbackrest
    $ chmod 750 /var/lib/pgbackrest
    $ chown postgres:postgres /var/lib/pgbackrest
    
  3. The default pgBackRest configuration file location is /etc/pgbackrest/pgbackrest.conf, but some systems continue to use the old path, /etc/pgbackrest.conf, which remains a valid alternative. If the former is not present in your system, create the latter.

    Access the file’s parent directory (either cd /etc/ or cd /etc/pgbackrest/), and make a backup copy of it:

    $ cp pgbackrest.conf pgbackrest.conf.bak
    

    Then use the following command to create a basic configuration file using the environment variables we created in a previous step:

    cat <<EOF > pgbackrest.conf
    [global] 
    
    # Server repo details
    repo1-path=/var/lib/pgbackrest 
    
    ### Retention ###
    #  - repo1-retention-archive-type
    #  - If set to full pgBackRest will keep archive logs for the number of full backups defined by repo-retention-archive
    repo1-retention-archive-type=full 
    
    # repo1-retention-archive
    #  - Number of backups worth of continuous WAL to retain
    #  - NOTE: WAL segments required to make a backup consistent are always retained until the backup is expired regardless of how this option is configured
    #  - If this value is not set and repo-retention-full-type is count (default), then the archive to expire will default to the repo-retention-full
    # repo1-retention-archive=2 
    
    # repo1-retention-full
    #  - Full backup retention count/time.
    #  - When a full backup expires, all differential and incremental backups associated with the full backup will also expire. 
    #  - When the option is not defined a warning will be issued. 
    #  - If indefinite retention is desired then set the option to the max value. 
    repo1-retention-full=4 
    
    # Server general options
    process-max=12
    log-level-console=info
    #log-level-file=debug
    log-level-file=info
    start-fast=y
    delta=y
    backup-standby=y 
    
    ########## Server TLS options ##########
    tls-server-address=*
    tls-server-cert-file=${CA_PATH}/${SRV_NAME}.crt
    tls-server-key-file=${CA_PATH}/${SRV_NAME}.key
    tls-server-ca-file=${CA_PATH}/ca.crt 
    
    ### Auth entry ###
    tls-server-auth=${NODE1_NAME}=cluster_1
    tls-server-auth=${NODE2_NAME}=cluster_1
    tls-server-auth=${NODE3_NAME}=cluster_1 
    
    ### Clusters and nodes ###
    [cluster_1]
    pg1-host=${NODE1_NAME}
    pg1-host-port=8432
    pg1-port=5432
    pg1-path=/var/lib/postgresql/15/main
    pg1-host-type=tls
    pg1-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg1-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg1-host-ca-file=${CA_PATH}/ca.crt
    pg1-socket-path=/var/run/postgresql 
    
    pg2-host=${NODE2_NAME}
    pg2-host-port=8432
    pg2-port=5432
    pg2-path=/var/lib/postgresql/15/main
    pg2-host-type=tls
    pg2-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg2-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg2-host-ca-file=${CA_PATH}/ca.crt
    pg2-socket-path=/var/run/postgresql 
    
    pg3-host=${NODE3_NAME}
    pg3-host-port=8432
    pg3-port=5432
    pg3-path=/var/lib/postgresql/15/main
    pg3-host-type=tls
    pg3-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg3-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg3-host-ca-file=${CA_PATH}/ca.crt
    pg3-socket-path=/var/run/postgresql
    EOF
    
    cat <<EOF > pgbackrest.conf
    [global] 
    
    # Server repo details
    repo1-path=/var/lib/pgbackrest 
    
    ### Retention ###
    #  - repo1-retention-archive-type
    #  - If set to full pgBackRest will keep archive logs for the number of full backups defined by repo-retention-archive
    repo1-retention-archive-type=full 
    
    # repo1-retention-archive
    #  - Number of backups worth of continuous WAL to retain
    #  - NOTE: WAL segments required to make a backup consistent are always retained until the backup is expired regardless of how this option is configured
    #  - If this value is not set and repo-retention-full-type is count (default), then the archive to expire will default to the repo-retention-full
    # repo1-retention-archive=2 
    
    # repo1-retention-full
    #  - Full backup retention count/time.
    #  - When a full backup expires, all differential and incremental backups associated with the full backup will also expire. 
    #  - When the option is not defined a warning will be issued. 
    #  - If indefinite retention is desired then set the option to the max value. 
    repo1-retention-full=4 
    
    # Server general options
    process-max=12
    log-level-console=info
    #log-level-file=debug
    log-level-file=info
    start-fast=y
    delta=y
    backup-standby=y 
    
    ########## Server TLS options ##########
    tls-server-address=*
    tls-server-cert-file=${CA_PATH}/${SRV_NAME}.crt
    tls-server-key-file=${CA_PATH}/${SRV_NAME}.key
    tls-server-ca-file=${CA_PATH}/ca.crt 
    
    ### Auth entry ###
    tls-server-auth=${NODE1_NAME}=cluster_1
    tls-server-auth=${NODE2_NAME}=cluster_1
    tls-server-auth=${NODE3_NAME}=cluster_1 
    
    ### Clusters and nodes ###
    [cluster_1]
    pg1-host=${NODE1_NAME}
    pg1-host-port=8432
    pg1-port=5432
    pg1-path=/var/lib/pgsql/15/data
    pg1-host-type=tls
    pg1-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg1-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg1-host-ca-file=${CA_PATH}/ca.crt
    pg1-socket-path=/var/run/postgresql 
    
    pg2-host=${NODE2_NAME}
    pg2-host-port=8432
    pg2-port=5432
    pg2-path=/var/lib/pgsql/15/data
    pg2-host-type=tls
    pg2-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg2-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg2-host-ca-file=${CA_PATH}/ca.crt
    pg2-socket-path=/var/run/postgresql 
    
    pg3-host=${NODE3_NAME}
    pg3-host-port=8432
    pg3-port=5432
    pg3-path=/var/lib/pgsql/15/data
    pg3-host-type=tls
    pg3-host-cert-file=${CA_PATH}/${SRV_NAME}.crt
    pg3-host-key-file=${CA_PATH}/${SRV_NAME}.key
    pg3-host-ca-file=${CA_PATH}/ca.crt
    pg3-socket-path=/var/run/postgresql
    EOF
    

    NOTE: The option backup-standby=y above indicates the backups should be taken from a standby server. If you are operating with a primary only, or if your secondaries are not configured with pgBackRest, set this option to n.

Create the certificate files

  1. Create the folder to store the certificates:

    $ mkdir -p ${CA_PATH}
    
  2. Create the certificates and keys

    $ openssl req -new -x509 -days 365 -nodes -out ${CA_PATH}/ca.crt -keyout ${CA_PATH}/ca.key -subj "/CN=root-ca"
    
  3. Create the certificate for the backup and the PostgreSQL servers

    $ for node in ${SRV_NAME} ${NODE1_NAME} ${NODE2_NAME} ${NODE3_NAME}
    do
    openssl req -new -nodes -out ${CA_PATH}/$node.csr -keyout ${CA_PATH}/$node.key -subj "/CN=$node";
    done
    
  4. Sign the certificates with the root-ca key

    $ for node in ${SRV_NAME} ${NODE1_NAME} ${NODE2_NAME} ${NODE3_NAME}
    do
    openssl x509 -req -in ${CA_PATH}/$node.csr -days 365 -CA ${CA_PATH}/ca.crt -CAkey ${CA_PATH}/ca.key -CAcreateserial -out ${CA_PATH}/$node.crt;
    done
    
  5. Remove temporary files, set ownership of the remaining files to the postgres user, and restrict their access:

    $ rm -f ${CA_PATH}/*.csr
    $ chown postgres:postgres -R ${CA_PATH}
    $ chmod 0600 ${CA_PATH}/*
    

Create the pgbackrest daemon service

  1. Create the systemd unit file at the path /etc/systemd/system/pgbackrest.service

    /etc/systemd/system/pgbackrest.service
    [Unit]
    Description=pgBackRest Server
    After=network.target
    
    [Service]
    Type=simple
    User=postgres
    Restart=always
    RestartSec=1
    ExecStart=/usr/bin/pgbackrest server
    #ExecStartPost=/bin/sleep 3
    #ExecStartPost=/bin/bash -c "[ ! -z $MAINPID ]"
    ExecReload=/bin/kill -HUP $MAINPID
    
    [Install]
    WantedBy=multi-user.target
    
  2. Reload, start, and enable the service

    $ systemctl daemon-reload
    $ systemctl start pgbackrest.service
    $ systemctl enable pgbackrest.service
    

Configure database servers

Run the following commands on node1, node2, and node3.

  1. Install pgBackRest package

    $ apt install percona-pgbackrest
    
    $ yum install percona-pgbackrest
    
  2. Export environment variables to simplify the config file creation:

    $ export NODE_NAME=`hostname -f`
    $ export SRV_NAME="bkp-srv"
    $ export CA_PATH="/etc/ssl/certs/pg_ha"
    
  3. Create the certificates folder:

    $ mkdir -p ${CA_PATH}
    
  4. Copy the .crt, .key certificate files and the ca.crt file from the backup server where they were created to every respective node. Then change the ownership to the postgres user and restrict their access. Use the following commands to achieve this:

    $ scp ${SRV_NAME}:${CA_PATH}/{$NODE_NAME.crt,$NODE_NAME.key,ca.crt} ${CA_PATH}/
    $ chown postgres:postgres -R ${CA_PATH}
    $ chmod 0600 ${CA_PATH}/* 
    
  5. Edit or create the configuration file which, as explained above, can be either at the /etc/pgbackrest/pgbackrest.conf or /etc/pgbackrest.conf path:

    pgbackrest.conf
    cat <<EOF > pgbackrest.conf
    [global]
    repo1-host=${SRV_NAME}
    repo1-host-user=postgres
    repo1-host-type=tls
    repo1-host-cert-file=${CA_PATH}/${NODE_NAME}.crt
    repo1-host-key-file=${CA_PATH}/${NODE_NAME}.key
    repo1-host-ca-file=${CA_PATH}/ca.crt
    
    # general options
    process-max=16
    log-level-console=info
    log-level-file=debug
    
    # tls server options
    tls-server-address=*
    tls-server-cert-file=${CA_PATH}/${NODE_NAME}.crt
    tls-server-key-file=${CA_PATH}/${NODE_NAME}.key
    tls-server-ca-file=${CA_PATH}/ca.crt
    tls-server-auth=${SRV_NAME}=cluster_1
    
    [cluster_1]
    pg1-path=/var/lib/postgresql/15/main
    EOF
    
    pgbackrest.conf
    cat <<EOF > pgbackrest.conf
    [global]
    repo1-host=${SRV_NAME}
    repo1-host-user=postgres
    repo1-host-type=tls
    repo1-host-cert-file=${CA_PATH}/${NODE_NAME}.crt
    repo1-host-key-file=${CA_PATH}/${NODE_NAME}.key
    repo1-host-ca-file=${CA_PATH}/ca.crt
    
    # general options
    process-max=16
    log-level-console=info
    log-level-file=debug
    
    # tls server options
    tls-server-address=*
    tls-server-cert-file=${CA_PATH}/${NODE_NAME}.crt
    tls-server-key-file=${CA_PATH}/${NODE_NAME}.key
    tls-server-ca-file=${CA_PATH}/ca.crt
    tls-server-auth=${SRV_NAME}=cluster_1
    
    [cluster_1]
    pg1-path=/var/lib/pgsql/15/data
    EOF
    
  6. Create the pgbackrest systemd unit file at the path /etc/systemd/system/pgbackrest.service

    /etc/systemd/system/pgbackrest.service
    [Unit]
    Description=pgBackRest Server
    After=network.target
    
    [Service]
    Type=simple
    User=postgres
    Restart=always
    RestartSec=1
    ExecStart=/usr/bin/pgbackrest server
    #ExecStartPost=/bin/sleep 3
    #ExecStartPost=/bin/bash -c "[ ! -z $MAINPID ]"
    ExecReload=/bin/kill -HUP $MAINPID
    
    [Install]
    WantedBy=multi-user.target
    
  7. Reload, start, and enable the service

    $ systemctl daemon-reload
    $ systemctl start pgbackrest
    $ systemctl enable pgbackrest
    

    The pgBackRest daemon listens on port 8432 by default:

    $ netstat -taunp
    Active Internet connections (servers and established)
    Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
    tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd           
    tcp        0      0 0.0.0.0:8432            0.0.0.0:*               LISTEN      40224/pgbackrest
    
  8. If you are using Patroni, change its configuration to use pgBackRest for archiving and restoring WAL files. Run this command only on one node, for example, on node1:

    $ patronictl -c /etc/patroni/patroni.yml edit-config
    
    /etc/patroni/patroni.yml
    postgresql:
      (...)
      parameters:
        (...)
        archive_command: pgbackrest --stanza=cluster_1 archive-push /var/lib/postgresql/15/main/pg_wal/%f
        (...)
      recovery_conf:
        (...)
        restore_command: pgbackrest --config=/etc/pgbackrest.conf --stanza=cluster_1 archive-get %f %p
        (...)
    
    /etc/patroni/patroni.yml
    postgresql:
      (...)
      parameters:
        archive_command: pgbackrest --stanza=cluster_1 archive-push /var/lib/pgsql/15/data/pg_wal/%f
        (...)
      recovery_conf:
        restore_command: pgbackrest --config=/etc/pgbackrest.conf --stanza=cluster_1 archive-get %f %p
        (...)
    

    Reload the changed configurations:

    $ patronictl -c /etc/patroni/postgresql.yml reload
    

    Note: When configuring a PostgreSQL server that is not managed by Patroni to archive/restore WALs from the pgBackRest server, edit the server’s main configuration file directly and adjust the archive_command and restore_command variables as shown above.

Create backups

Run the following commands on the backup server:

  1. Create the stanza. A stanza is the configuration for a PostgreSQL database cluster that defines where it is located, how it will be backed up, archiving options, etc.

    $ sudo -iu postgres pgbackrest --stanza=cluster_1 stanza-create
    
  2. Create a full backup

    $ sudo -iu postgres pgbackrest --stanza=cluster_1 --type=full backup
    
  3. Check backup info

    $ sudo -iu postgres pgbackrest --stanza=cluster_1 info
    
  4. Expire (remove) a backup:

    $ sudo -iu postgres pgbackrest --stanza=cluster_1 expire --set=<BACKUP_ID>
    

Test PostgreSQL cluster

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