Add support for postgres replication slot (#31)

Signed-off-by: souravbiswassanto <[email protected]>
kubedb · Mar 15, 2024 · 4472844 · 4472844
1 parent 06ba93a
commit 4472844
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Showing 36 changed files with 508 additions and 65 deletions.
diff --git a/role_scripts/10/primary/start.sh b/role_scripts/10/primary/start.sh
@@ -20,8 +20,13 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+#echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 echo "archive_mode = always" >>/tmp/postgresql.conf
 echo "archive_command = '/bin/true'" >>/tmp/postgresql.conf

diff --git a/role_scripts/10/standby/ha_backup_job.sh b/role_scripts/10/standby/ha_backup_job.sh
@@ -77,9 +77,15 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-echo "shared_preload_libraries = 'pg_stat_statements'" >>/tmp/postgresql.conf
+#echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
 
+echo "shared_preload_libraries = 'pg_stat_statements'" >>/tmp/postgresql.conf
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf

diff --git a/role_scripts/10/standby/run.sh b/role_scripts/10/standby/run.sh
@@ -66,6 +66,30 @@ while true; do
     sleep 2
 done
 
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  while true; do
+      echo "Create replication slot on primary"
+      if [[ "${SSL:-0}" == "ON" ]]; then
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres "sslmode=$SSL_MODE sslrootcert=/tls/certs/client/ca.crt sslcert=/tls/certs/client/client.crt sslkey=/tls/certs/client/client.key" --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      else
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres --no-password --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      fi
+      # check if current pod became leader itself
+
+      if [[ $output == *"(1 row)"* || $output == *"already exists"* ]]; then
+        break
+      fi
+
+      if [[ -e "/run_scripts/tmp/pg-failover-trigger" ]]; then
+          echo "Postgres promotion trigger_file found. Running primary run script"
+          /run_scripts/role/run.sh
+      fi
+      sleep 2
+  done
+fi
+
+
 if [[ ! -e "$PGDATA/PG_VERSION" ]]; then
     echo "take base basebackup..."
     # get basebackup
@@ -91,14 +115,19 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+#echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
 
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf
 echo "archive_command = '/bin/true'" >>/tmp/postgresql.conf
 echo "shared_preload_libraries = 'pg_stat_statements'" >>/tmp/postgresql.conf
-
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 if [ "$STANDBY" == "hot" ]; then
     echo "hot_standby = on" >>/tmp/postgresql.conf
 fi

diff --git a/role_scripts/10/standby/warm_stanby.sh b/role_scripts/10/standby/warm_stanby.sh
@@ -22,8 +22,13 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+#echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf

diff --git a/role_scripts/11/primary/start.sh b/role_scripts/11/primary/start.sh
@@ -20,8 +20,13 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 echo "archive_mode = always" >>/tmp/postgresql.conf
 

diff --git a/role_scripts/11/standby/ha_backup_job.sh b/role_scripts/11/standby/ha_backup_job.sh
@@ -77,8 +77,13 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf

diff --git a/role_scripts/11/standby/run.sh b/role_scripts/11/standby/run.sh
@@ -66,6 +66,29 @@ while true; do
     sleep 2
 done
 
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  while true; do
+      echo "Create replication slot on primary"
+      if [[ "${SSL:-0}" == "ON" ]]; then
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres "sslmode=$SSL_MODE sslrootcert=/tls/certs/client/ca.crt sslcert=/tls/certs/client/client.crt sslkey=/tls/certs/client/client.key" --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      else
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres --no-password --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      fi
+      # check if current pod became leader itself
+
+      if [[ $output == *"(1 row)"* || $output == *"already exists"* ]]; then
+        break
+      fi
+
+      if [[ -e "/run_scripts/tmp/pg-failover-trigger" ]]; then
+          echo "Postgres promotion trigger_file found. Running primary run script"
+          /run_scripts/role/run.sh
+      fi
+      sleep 2
+  done
+fi
+
 if [[ ! -e "$PGDATA/PG_VERSION" ]]; then
     echo "take base basebackup..."
     # get basebackup
@@ -91,8 +114,13 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf

diff --git a/role_scripts/11/standby/warm_stanby.sh b/role_scripts/11/standby/warm_stanby.sh
@@ -22,8 +22,13 @@ touch /tmp/postgresql.conf
 echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 echo "archive_mode = always" >>/tmp/postgresql.conf

diff --git a/role_scripts/12/primary/start.sh b/role_scripts/12/primary/start.sh
@@ -20,8 +20,13 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 # we are not doing any archiving by default but it's better to have this config in our postgresql.conf file in case of customization.

diff --git a/role_scripts/12/standby/ha_backup_job.sh b/role_scripts/12/standby/ha_backup_job.sh
@@ -72,8 +72,18 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+#echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
 
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  echo "primary_slot_name = "$CLEAN_HOSTNAME"" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 # we are not doing any archiving by default but it's better to have this config in our postgresql.conf file in case of customization.

diff --git a/role_scripts/12/standby/run.sh b/role_scripts/12/standby/run.sh
@@ -66,6 +66,30 @@ while true; do
     sleep 2
 done
 
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  while true; do
+      echo "Create replication slot on primary"
+      if [[ "${SSL:-0}" == "ON" ]]; then
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres "sslmode=$SSL_MODE sslrootcert=/tls/certs/client/ca.crt sslcert=/tls/certs/client/client.crt sslkey=/tls/certs/client/client.key" --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      else
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres --no-password --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      fi
+      # check if current pod became leader itself
+
+      if [[ $output == *"(1 row)"* || $output == *"already exists"* ]]; then
+        break
+      fi
+
+      if [[ -e "/run_scripts/tmp/pg-failover-trigger" ]]; then
+          echo "Postgres promotion trigger_file found. Running primary run script"
+          /run_scripts/role/run.sh
+      fi
+      sleep 2
+  done
+fi
+
+
 if [[ ! -e "$PGDATA/PG_VERSION" ]]; then
     echo "take base basebackup..."
     mkdir -p "$PGDATA"
@@ -86,7 +110,18 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  echo "primary_slot_name = "$CLEAN_HOSTNAME"" >>/tmp/postgresql.conf
+fi
+
 
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 

diff --git a/role_scripts/12/standby/warm_stanby.sh b/role_scripts/12/standby/warm_stanby.sh
@@ -20,7 +20,17 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+# echo "wal_keep_segments = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  echo "primary_slot_name = "$CLEAN_HOSTNAME"" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 

diff --git a/role_scripts/13/primary/start.sh b/role_scripts/13/primary/start.sh
@@ -20,8 +20,13 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_size = 1024" >>/tmp/postgresql.conf
-
+# echo "wal_keep_size = 1024" >>/tmp/postgresql.conf
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_segments = 64" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 # we are not doing any archiving by default but it's better to have this config in our postgresql.conf file in case of customization.

diff --git a/role_scripts/13/standby/ha_backup_job.sh b/role_scripts/13/standby/ha_backup_job.sh
@@ -72,7 +72,17 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_size = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+# echo "wal_keep_size = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_size = 1024" >>/tmp/postgresql.conf
+fi
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  echo "primary_slot_name = "$CLEAN_HOSTNAME"" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 

diff --git a/role_scripts/13/standby/run.sh b/role_scripts/13/standby/run.sh
@@ -66,6 +66,30 @@ while true; do
     sleep 2
 done
 
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  while true; do
+      echo "Create replication slot on primary"
+      if [[ "${SSL:-0}" == "ON" ]]; then
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres "sslmode=$SSL_MODE sslrootcert=/tls/certs/client/ca.crt sslcert=/tls/certs/client/client.crt sslkey=/tls/certs/client/client.key" --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      else
+          output=$(psql -h "$PRIMARY_HOST" --username=postgres --no-password --command="SELECT pg_create_physical_replication_slot('${CLEAN_HOSTNAME}', true);" 2>&1 || true)
+      fi
+      # check if current pod became leader itself
+
+      if [[ $output == *"(1 row)"* || $output == *"already exists"* ]]; then
+        break
+      fi
+
+      if [[ -e "/run_scripts/tmp/pg-failover-trigger" ]]; then
+          echo "Postgres promotion trigger_file found. Running primary run script"
+          /run_scripts/role/run.sh
+      fi
+      sleep 2
+  done
+fi
+
+
 if [[ ! -e "$PGDATA/PG_VERSION" ]]; then
     echo "take base basebackup..."
     mkdir -p "$PGDATA"
@@ -86,8 +110,17 @@ echo "wal_level = replica" >>/tmp/postgresql.conf
 echo "shared_buffers = $SHARED_BUFFERS" >>/tmp/postgresql.conf
 echo "max_wal_senders = 90" >>/tmp/postgresql.conf # default is 10.  value must be less than max_connections minus superuser_reserved_connections. ref: https://www.postgresql.org/docs/11/runtime-config-replication.html#GUC-MAX-WAL-SENDERS
 
-echo "wal_keep_size = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
-
+# echo "wal_keep_size = 1024" >>/tmp/postgresql.conf #it was  "wal_keep_segments" in earlier version. changed in version 13
+if [ ! -z "${WAL_RETAIN_PARAM:-}" ] && [ ! -z "${WAL_RETAIN_AMOUNT:-}" ]; then
+    echo "${WAL_RETAIN_PARAM}=${WAL_RETAIN_AMOUNT}" >>/tmp/postgresql.conf
+else
+  echo "wal_keep_size = 1024" >>/tmp/postgresql.conf
+fi
+if [[ "$WAL_LIMIT_POLICY" == "ReplicationSlot" ]]; then
+  CLEAN_HOSTNAME="${HOSTNAME//[^[:alnum:]]/}"
+  echo "primary_slot_name = "$CLEAN_HOSTNAME"" >>/tmp/postgresql.conf
+fi
+echo "max_replication_slots = 90" >>/tmp/postgresql.conf
 echo "wal_log_hints = on" >>/tmp/postgresql.conf
 
 # we are not doing any archiving by default but it's better to have this config in our postgresql.conf file in case of customization.