Jeff Moe
c8fba3a2c2
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6 years ago | |
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| README.md | 6 years ago | |
README.md
repmgr Postgres cluster
https://repmgr.org/docs/repmgr.html
Postgres 11 with streaming replication and backups.
Servers
pg-oca --- Master Postgres Server pg-oca-rep1 --- Standby Postgres Server pg-oca-hdd --- Standby Postgres Server pg-oca-barman --- Postgres Backup Server pg-oca-witness-1 --- Postgres Witness Server
Each server has two ethernet interfaces. One for the VPN for ssh, and the second for database backend communication.
Install
Add Postgres community repository to each server.
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
echo "deb http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main" > /etc/apt/sources.list.d/pgdg.list
Install Postgres 11 client and repmgr on all servers.
apt update apt install postgresql-client-11 postgresql-11-repmgr
Install Postgres 11 server on pg-oca and install repmgr module. apt install postgresql-11 postgresql-11-repmgr
System Configuration
Configure firewall.
#=============== Postgres Cluster =================== -A INPUT --dest 10.104.11.0/24 -p icmp -m icmp --icmp-type 8 -j ACCEPT -A INPUT --dest 10.53.1.0/24 -p icmp -m icmp --icmp-type 8 -j ACCEPT -A INPUT -p tcp --dest 10.53.1.0/24 --dport 61 -j ACCEPT -A INPUT -p tcp --dest 10.53.1.0/24 --dport 5432 -j ACCEPT #=============== End of Postgres Cluster =============
Set up /etc/hosts on all nodes: cat >> /etc/hosts << EOF 10.104.11.44 oca 10.104.11.116 pg-oca 10.104.11.131 pg-oca-rep1 10.104.11.132 pg-oca-hdd 10.104.11.133 pg-oca-barman 10.104.11.134 pg-oca-witness-1
10.53.1.44 db-oca 10.53.1.116 db-pg-oca 10.53.1.131 db-pg-oca-rep1 10.53.1.132 db-pg-oca-hdd 10.53.1.133 db-pg-oca-barman 10.53.1.134 db-pg-oca-witness-1 EOF
Configure base Postgres 11 server. pg_hba.conf and tuning
On master server pg-oca and pg-oca-rep1
cat > /etc/postgresql/11/main/conf.d/replication.conf << EOF
Enable replication connections; set this figure to at least one more
than the number of standbys which will connect to this server
(note that repmgr will execute pg_basebackup in WAL streaming mode,
which requires two free WAL senders)
max_wal_senders = 10
Ensure WAL files contain enough information to enable read-only queries
on the standby.
PostgreSQL 9.5 and earlier: one of 'hot_standby' or 'logical'
PostgreSQL 9.6 and later: one of 'replica' or 'logical'
('hot_standby' will still be accepted as an alias for 'replica')
See: https://www.postgresql.org/docs/current/static/runtime-config-wal.html#GUC-WAL-LEVEL
wal_level = 'replica'
Enable read-only queries on a standby
(Note: this will be ignored on a primary but we recommend including
it anyway)
hot_standby = on
Enable WAL file archiving
archive_mode = on
Set archive command to a script or application that will safely store
you WALs in a secure place. /bin/true is an example of a command that
ignores archiving. Use something more sensible.
XXX
archive_command = '/bin/true'
If you have configured "pg_basebackup_options"
in "repmgr.conf" to include the setting "--xlog-method=fetch" (from
PostgreSQL 10 "--wal-method=fetch"), and you have not set
"restore_command" in "repmgr.conf"to fetch WAL files from another
source such as Barman, you'll need to set "wal_keep_segments" to a
high enough value to ensure that all WAL files generated while
the standby is being cloned are retained until the standby starts up.
wal_keep_segments = 5000
EOF
Set up pg_hba.conf on hosts pg-oca and pg-oca-rep1
cat > /etc/postgresql/11/main/pg_hba.conf << EOF
Local
local all all peer local all postgres peer host all all 127.0.0.1/32 md5
Replication
local replication repmgr trust host replication repmgr 127.0.0.1/32 trust host replication repmgr 10.53.1.116/32 trust host replication repmgr 10.53.1.131/32 trust host replication repmgr 10.53.1.132/32 trust host replication repmgr 10.53.1.133/32 trust host replication repmgr 10.53.1.134/32 trust
repmgr
local repmgr repmgr trust host repmgr repmgr 127.0.0.1/32 trust host repmgr repmgr 10.53.1.116/32 trust host repmgr repmgr 10.53.1.131/32 trust host repmgr repmgr 10.53.1.132/32 trust host repmgr repmgr 10.53.1.133/32 trust host repmgr repmgr 10.53.1.134/32 trust
OCA
host all oca 10.53.1.44/32 trust host all postgres 10.53.1.44/32 trust EOF
Set up configuration. Note to change listen_addresses below:
cat > /etc/postgresql/11/main/conf.d/pgconfig.conf << EOF
Memory Configuration
shared_buffers = 8GB effective_cache_size = 24GB work_mem = 128MB maintenance_work_mem = 2GB
Checkpoint Related Configuration
min_wal_size = 1GB max_wal_size = 3GB checkpoint_completion_target = 0.9 wal_buffers = 16MB
Network Related Configuration
XXX Set
#listen_addresses = '10.53.1.130' max_connections = 256
Hard Drive Configuration
random_page_cost = 1.1 effective_io_concurrency = 300
Adjust the minimum time to collect data
log_min_duration_statement = '10s' log_autovacuum_min_duration = 0 EOF
Configure ssh between nodes. Which users?
repmgr Cluster Master Configuration
Set up nodes to communicate.
Node pg-oca is master. Node pg-oca-rep1 does streaming replication of pg-oca. Node pg-oca-hdd does streaming replication of pg-oca-rep1 and stores to hard disk platters instead of NVMe drives. Node pg-oca-barman runs the Postgres barman backup system, and does backups of pg-oca-rep1. Node pg-oca-witness-1 is a Postgres witness server. It isn't needed at present.
Run on pg-oca: sudo su - postgres createuser -s repmgr createdb repmgr -O repmgr
repmgr Cluster Standby Configuration
On the standby, do not create a PostgreSQL instance.
From pg-oca: Check the primary database is reachable from the standby using psql:
psql 'host=db-pg-oca user=repmgr dbname=repmgr connect_timeout=2'
Set up Master repmgr
cat > /etc/repmgr.conf << EOF node_id=1 node_name=pg-oca conninfo='host=db-pg-oca user=repmgr dbname=repmgr connect_timeout=2' data_directory='/var/lib/postgresql/11/main' pg_bindir='/usr/lib/postgresql/11/bin' repmgr_bindir='/usr/lib/postgresql/11/bin' EOF
Register primary server:
sudo su - postgres repmgr -f /etc/repmgr.conf primary register
Clone Standby Server
Log into pg-oca-rep1
cat > /etc/repmgr.conf << EOF node_id=2 node_name=pg-oca-rep1 conninfo='host=db-pg-oca-rep1 user=repmgr dbname=repmgr connect_timeout=2' data_directory='/var/lib/postgresql/11/main' pg_bindir='/usr/lib/postgresql/11/bin' repmgr_bindir='/usr/lib/postgresql/11/bin' EOF
systemctl stop postgresql
sudo su - postgres Test it, dry run repmgr -h db-pg-oca -U repmgr -d repmgr -f /etc/repmgr.conf standby clone --force --dry-run
If good, then run it: repmgr -h db-pg-oca -U repmgr -d repmgr -f /etc/repmgr.conf standby clone --force
Then as root, start server: systemctl start postgresql
As user postgres: sudo su - postgres repmgr standby register
Check it out: repmgr cluster show
Create Database
Log into main server pg-oca. sudo su - postgres createuser --createdb oca createdb --owner=oca oca