library/roles/postgresql: Lots of changes to implement the pgpool installation better.

d4science-ghn-cluster/group_vars/postgres_pgpool_test: Changed some variables.

postgresql/defaults/main.yml

@@ -20,6 +20,7 @@ psql_db_size_c: 170000000
 psql_listen_on_ext_int: False
 psql_use_alternate_data_dir: False
 psql_data_dir: '/var/lib/postgresql/{{ psql_version }}'
+psql_log_dir: /var/log/postgresql
 psql_conf_parameters:
   - { name: 'max_connections', value: '100', set: 'False' }
   - { name: 'ssl', value: 'true', set: 'False' }
@@ -28,7 +29,6 @@ psql_conf_parameters:
   - { name: 'work_mem', value: '1MB', set: 'False' }
   - { name: 'maintenance_work_mem', value: '16MB', set: 'False' }
   - { name: 'max_stack_depth', value: '2MB', set: 'False' }
-  - { name: 'wal_level', value: 'minimal', set: 'False' }
   - { name: 'checkpoint_segments', value: '3', set: 'False' }
   - { name: 'max_files_per_process', value: '1000', set: 'False' }
 
@@ -96,13 +96,15 @@ pgpool_insert_lock: 'on'
 pgpool_lobj_lock_table: ''
 pgpool_replication_stop_on_mismatch: 'on'
 pgpool_failover_if_affected_tuples_mismatch: 'off'
+pgpool_recovery_timeout: 30
+pgpool_client_idle_limit_in_recovery: -1
 pgpool_load_balance_mode: 'on'
 pgpool_ignore_leading_white_space: 'on'
 pgpool_recovery_user: postgres
 # pgpool_recovery_user_pwd: use a vault file for this one
 pgpool_recovery_stage1_script: pgpool_recovery_stage_1
 pgpool_recovery_stage2_script: pgpool_recovery_stage_2
-pgpool_remote_start_script: postgresql_remote_start
+pgpool_remote_start_script: pgpool_remote_start
 pgpool_white_function_list: ''
 pgpool_black_function_list: 'nextval,setval'
 pgpool_allow_sql_comments: 'on'
@@ -115,6 +117,23 @@ pgpool_memqcache_memcached_port: 11211
 pgpool_memqcache_expire: 0
 pgpool_memqcache_auto_cache_invalidation: 'on'
 
+# WAL files archiving is mandatory for pgpool recovery
+psql_wal_files_archiving_enabled: '{{ psql_pgpool_install }}'
+psql_restart_after_wal_enabling: True
+psql_wal_archiving_log_dir: '{{ psql_data_dir }}/archive_log'
+psql_base_backup_dir: '{{ pg_backup_base_dir }}/base_backup'
+psql_wal_files_conf:
+  - { name: 'wal_level', value: 'archive', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'wal_sync_method', value: 'fdatasync', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'full_page_writes', value: 'on', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'wal_log_hints', value: 'on', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'archive_mode', value: 'on', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'archive_command', value: "'test ! -f {{ psql_wal_archiving_log_dir }}/%f && cp %p {{ psql_wal_archiving_log_dir }}/%f'", set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'archive_timeout', value: '120', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'max_wal_senders', value: '5', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'wal_sender_timeout', value: '60s', set: '{{ psql_wal_files_archiving_enabled }}' }
+  - { name: 'max_replication_slots', value: '5', set: '{{ psql_wal_files_archiving_enabled }}' }
+
   
 # postgis
 postgres_install_gis_extensions: False
@@ -130,7 +149,8 @@ pg_backup_retain_copies: 15
 pg_backup_build_db_list: "no"
 # Dynamically created from psql_db_data if pg_backup_db_list is not set
 #pg_backup_db_list: '{{ psql_db_name}}'
-pg_backup_destdir: /var/lib/pgsql/backups
+pg_backup_base_dir: /var/lib/pgsql
+pg_backup_destdir: '{{ pg_backup_base_dir }}/backups'
 pg_backup_logdir: /var/log/postgresql
 pg_backup_logfile: '{{ pg_backup_logdir }}/postgresql-backup.log'
 pg_backup_use_auth: "yes"

postgresql/handlers/main.yml

@@ -13,5 +13,11 @@
   ignore_errors: True
 
 - name: Restart pgpool2
-  service: name=pgpool2 state=reloaded
+  service: name=pgpool2 state=restarted
   when: pgpool_enabled
+
+- name: Restart postgresql with pgpool config
+  service: name=postgresql state=restarted
+  when:
+    - postgresql_enabled
+    - psql_restart_after_wal_enabling

postgresql/tasks/configure-access.yml

@@ -25,12 +25,12 @@
 
 - name: Set the postgresql listen port
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=port value="{{ psql_db_port }}"
-  notify: Restart postgresql
+  register: restart_postgresql
   tags: [ 'postgresql', 'postgres', 'pg_conf' ]
 
 - name: We want postgres listen on the public IP
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=listen_addresses value="'*'"
-  notify: Restart postgresql
+  register: restart_postgresql
   when:
     - psql_listen_on_ext_int
     - psql_db_data is defined
@@ -38,7 +38,7 @@
 
 - name: If postgresql is only accessed from localhost make it listen only on the localhost interface
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=listen_addresses value="'localhost'"
-  notify: Restart postgresql
+  register: restart_postgresql
   when:
     - not psql_listen_on_ext_int
     - psql_db_data is defined
@@ -46,19 +46,19 @@
 
 - name: Log the connections
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=log_connections value="on"
-  notify: Restart postgresql
+  register: restart_postgresql
   when: psql_db_data is defined
   tags: [ 'postgresql', 'postgres', 'pg_conf' ]
 
 - name: Log the disconnections
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=log_disconnections value="on"
-  notify: Restart postgresql
+  register: restart_postgresql
   when: psql_db_data is defined
   tags: [ 'postgresql', 'postgres', 'pg_conf' ]
 
 - name: Log the hostnames
   action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key=log_hostname value="on"
-  notify: Restart postgresql
+  register: restart_postgresql
   when:
     - psql_listen_on_ext_int
     - psql_db_data is defined
@@ -71,3 +71,9 @@
     - postgresql.conf
   tags: [ 'postgresql', 'postgres', 'pg_hba', 'pg_conf' ]
 
+- name: Restart the postgresql server after changing parameters that need a restart
+  service: name=postgresql state=restarted
+  when:
+    - postgresql_enabled
+    - ( restart_postgresql | changed )
+  tags: [ 'postgresql', 'postgres', 'pg_hba', 'pg_conf' ]

postgresql/tasks/postgres_pgpool.yml

@@ -6,7 +6,7 @@
   notify: Restart postgresql
   tags: [ 'postgresql', 'postgres', 'pgpool' ]
 
-- name: Add the user that will manage the recovery, if not postgres
+- name: Add the postgres user that will manage the recovery, if not postgres
   become: True
   become_user: postgres
   postgresql_user: user={{ pgpool_recovery_user }} password={{ pgpool_recovery_user_pwd }} role_attr_flags=REPLICATION port={{ psql_db_port }}
@@ -27,6 +27,17 @@
   notify: Reload postgresql
   tags: [ 'postgresql', 'postgres', 'pgpool' ]
 
+- name: Add the system user that will manage the recovery, if not postgres
+  user: user={{ pgpool_recovery_user }} password={{ pgpool_recovery_user_pwd | password_hash('sha512') }} groups=postgres shell=/bin/bash system=yes
+  when:
+    - ('{{ pgpool_recovery_user }}' != 'postgres')
+    - pgpool_recovery_user_pwd is defined
+  tags: [ 'postgresql', 'postgres', 'pgpool' ]
+
+- name: Create the ssh keys for the recovery user
+  user: user={{ pgpool_recovery_user }} generate_ssh_key=yes ssh_key_bits=2048 ssh_key_file=.ssh/id_rsa ssh_key_type=rsa
+  tags: [ 'postgresql', 'postgres', 'pgpool' ]
+
 - name: Install the pgpool recovery and remote restart scripts. They assume that the postgresql hosts can talk to each other
   template: src={{ item.1 }}.j2 dest={{ item.0.backend_data_directory }}/{{ item.1 }} owner=postgres group=postgres mode=0500
   with_nested: 
@@ -34,3 +45,23 @@
     - [ '{{ pgpool_recovery_stage1_script }}', '{{ pgpool_recovery_stage2_script }}', '{{ pgpool_remote_start_script }}' ]
   tags: [ 'postgresql', 'postgres', 'pgpool' ]
 
+- name: Set the postgresql configuration parameters needed by pgpool
+  action: configfile path=/etc/postgresql/{{ psql_version }}/main/postgresql.conf key={{ item.name }} value="{{ item.value }}"
+  with_items: '{{ psql_wal_files_conf }}'
+  when:
+    - item.set
+    - psql_wal_files_archiving_enabled
+  notify: Restart postgresql with pgpool config
+  tags: [ 'postgresql', 'postgres', 'pg_conf', 'pgpool' ]
+
+- name: Install the sudoers config that permits the postgres user to restart the service after a recovery
+  template: src=postgresql-sudoers.j2 dest=/etc/sudoers.d/postgres-pgpool owner=root group=root mode=0440
+  tags: [ 'postgres', 'postgresql', 'sudo', 'pgpool' ]
+
+- name: Install a script that cleans up the wal log archives
+  template: src=postgresql_wal_backup_and_removal.j2 dest=/usr/local/sbin/postgresql_wal_backup_and_removal owner=root group=root mode=0755
+  tags: [ 'postgresql', 'postgres', 'pgpool' ]
+
+- name: Install a cron job to cleanup the wal log archives
+  cron: name="Clean up the postgresql WAL log archives" user=postgres job="/usr/local/sbin/postgresql_wal_backup_and_removal > {{ psql_log_dir }}/wal_removal.log 2>&1" special_time=daily
+  tags: [ 'postgresql', 'postgres', 'pgpool' ]

postgresql/tasks/postgresql-backup.yml

@@ -18,3 +18,12 @@
 - name: Create the postgresql backups data directory
   file: dest={{ pg_backup_destdir }} owner=postgres group=postgres mode=700 recurse=yes state=directory
   tags: [ 'pg_backup', 'postgresql', 'postgres' ]
+
+- name: Create the postgresql WAL files backup directories
+  file: dest={{ item }} owner=postgres group=postgres mode=700 recurse=yes state=directory
+  with_items:
+    - '{{ psql_wal_archiving_log_dir }}'
+    - '{{ psql_base_backup_dir }}'
+  when: psql_wal_files_archiving_enabled
+  tags: [ 'pg_backup', 'postgresql', 'postgres' ]
+

postgresql/templates/pgpool.conf.j2

@@ -430,11 +430,11 @@ recovery_1st_stage_command = '{{ pgpool_recovery_stage1_script }}'
                                    # Executes a command in first stage
 recovery_2nd_stage_command = '{{ pgpool_recovery_stage2_script }}'
                                    # Executes a command in second stage
-recovery_timeout = 90
+recovery_timeout = {{ pgpool_recovery_timeout }}
                                    # Timeout in seconds to wait for the
                                    # recovering node's postmaster to start up
                                    # 0 means no wait
-client_idle_limit_in_recovery = 0
+client_idle_limit_in_recovery = {{ pgpool_client_idle_limit_in_recovery }}
                                    # Client is disconnected after being idle
                                    # for that many seconds in the second stage
                                    # of online recovery

postgresql/templates/pgpool_recovery_stage_1.j2

@@ -1,10 +1,31 @@
 #!/bin/bash
-DATA=$1
+# PGpool stage 1 recovery script
+# Reference: http://michael.stapelberg.de/Artikel/replicated_postgresql_with_pgpool
+#
+TS=$(date +%Y-%m-%d_%H-%M-%S)
+MASTER_HOST=$(hostname -f)
+MASTER_DATA=$1
 RECOVERY_TARGET=$2
 RECOVERY_DATA=$3
 
-psql -c "select pg_start_backup('pgpool-recovery')" postgres
+# Move the PostgreSQL data directory out of our way.
-echo "restore_command = 'scp $HOSTNAME:{{ psql_data_dir }}/archive_log/%f %p'" > {{ psql_data_dir }}/recovery.conf
+ssh -T $RECOVERY_TARGET \
-tar -C {{ psql_data_dir }}/ -zcf pgsql.tar.gz main
+    "[ -d $RECOVERY_DATA ] && mv $RECOVERY_DATA $RECOVERY_DATA.$TS"
-psql -c 'select pg_stop_backup()' postgres
+
-scp pgsql.tar.gz $RECOVERY_TARGET:$RECOVERY_DATA
+# We only use archived WAL logs during recoveries, so delete all
+# logs from the last recovery to limit the growth.
+rm $MASTER_DATA/archive_log/*
+
+# With this file present, our archive_command will actually
+# archive WAL files.
+touch $MASTER_DATA/archive_log/backup_in_progress
+
+# Perform a backup of the database.
+ssh -T $RECOVERY_TARGET \
+    "pg_basebackup -h $MASTER_HOST -D $RECOVERY_DATA --xlog"
+
+# Configure the restore_command to use the archive_log WALs we’ll copy
+# over in 2nd_stage.sh.
+echo "restore_command = 'cp $RECOVERY_DATA/archive_log/%f %p'" | \
+    ssh -T $RECOVERY_TARGET "cat > $RECOVERY_DATA/recovery.conf"
+EOF

postgresql/templates/pgpool_recovery_stage_2.j2

@@ -1,11 +1,11 @@
 #!/bin/bash
 # Online recovery 2nd stage script
+# Reference: http://michael.stapelberg.de/Artikel/replicated_postgresql_with_pgpool
 #
-datadir=$1       # master dabatase cluster
+MASTER_DATA=$1
-DEST=$2          # hostname of the DB node to be recovered
+RECOVERY_TARGET=$2
-DESTDIR=$3       # database cluster of the DB node to be recovered
+RECOVERY_DATA=$3
 port={{ psql_db_port }}        # PostgreSQL port number
-archdir={{ psql_data_dir }}/archive_log    # archive log directory
 
 # Force to flush current value of sequences to xlog
 psql -p $port -t -c 'SELECT datname FROM pg_database WHERE NOT datistemplate AND datallowconn' template1|
@@ -16,4 +16,15 @@ do
   fi
 done
 
-psql -p $port -c "SELECT pgpool_switch_xlog('$archdir')" template1
+# Flush all transactions to disk. Since pgpool stopped all connections,
+# there cannot be any data that does not reside on disk until the
+# to-be-recovered host is back on line.
+psql -p $port -c "SELECT pgpool_switch_xlog('$MASTER_DATA/archive_log')" template1
+
+# Copy over all archive logs at once.
+rsync -avx --delete $MASTER_DATA/archive_log/ \
+    $RECOVERY_TARGET:$RECOVERY_DATA/archive_log/
+
+# Delete the flag file to disable WAL archiving again.
+rm $MASTER_DATA/archive_log/backup_in_progress
+EOF

postgresql/templates/pgpool_remote_start.j2

@@ -3,6 +3,6 @@ DEST=$1
 DESTDIR=$2
 
 # Deploy a base backup
-ssh -T $DEST 'cd {{ psql_data_dir }}; tar zxf pgsql.tar.gz' 2>/dev/null 1>/dev/null < /dev/null
+#ssh -T $DEST 'cd {{ psql_data_dir }}; tar zxf pgsql.tar.gz' 2>/dev/null 1>/dev/null < /dev/null
 # Startup PostgreSQL server
 ssh -T $DEST sudo /etc/init.d/postgresql start 2>/dev/null 1>/dev/null < /dev/null

postgresql/templates/postgresql-sudoers.j2

@@ -0,0 +1,3 @@
+postgres  ALL=(ALL) NOPASSWD:   /etc/init.d/postgres*
+
+

postgresql/templates/postgresql_wal_backup_and_removal.j2

@@ -1,16 +1,16 @@
 #!/bin/bash
 
-BASE_BACKUP_DIR=/var/lib/pgsql/base_backup
+BASE_BACKUP_DIR={{ psql_base_backup_dir }}
-WAL_ARCHIVES_LOG_DIR=/var/lib/postgresql/9.5/archive_log
+WAL_ARCHIVES_LOG_DIR={{ psql_wal_archiving_log_dir }}
 WAL_LATEST_BACKUP=
 
 # The base backup dir needs to be empty
 
 rm -f $BASE_BACKUP_DIR/*
-pg_basebackup -F t -z -D /var/lib/pgsql/base_backup
+pg_basebackup -F t -z -D $BASE_BACKUP_DIR
 
 cd $WAL_ARCHIVES_LOG_DIR
-WAL_LATEST_BACKUP=$( /bin/ls -1 *.backup | sort | tail -1 )
+WAL_LATEST_BACKUP=$( /bin/ls -1tr *.backup | tail -1 )
 pg_archivecleanup $WAL_ARCHIVES_LOG_DIR $WAL_LATEST_BACKUP
 
 exit $?

postgresql/templates/wal_archive_cleanup.j2

@@ -1,6 +0,0 @@
-#!/bin/bash
-
-su - postgres -c "/usr/local/sbin/postgresql_wal_backup_and_removal > /var/log/postgresql/wal_removal.log 2>&1"
-
-exit 0
-