standby-clone: Allow cloning of standby server with pg_basebackup

Right now the role assumes you have a base backup available with
Barman. However if you don't have an initial barman backup you might
want to clone the primary server directly to setup your standby
server.

This PR adds a new `primary.pg_basebackup` option to the cluster
configuration which if enabled (set to `true`) will create a
`/root/standby-clone-{{ postgres_version }}-{{ postgres_cluster_name }}.sh`
script on the standby server which helps to initialise a standby
server.

⚠️ Breaking change: the current role behavior which creates a cloning
script fetching the initial backup from barman will not be
enabled by default anymore. You will need to add the new
`primary.restore_barman_directory` option in your role
configuration to do so. ⚠️

1 files changed, 49 insertions, 0 deletions

diff --git a/templates/standby-pg_basebackup-clone.sh.j2 b/templates/standby-pg_basebackup-clone.sh.j2
new file mode 100755
index 0000000..ca34a05
--- /dev/null
+++ b/templates/standby-pg_basebackup-clone.sh.j2
@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# {{ ansible_managed }}
+
+set -eo pipefail
+
+CLUSTER_VERSION="{{ postgres_version }}"
+CLUSTER_NAME="{{ postgres_cluster_name }}"
+PRIMARY_CLUSTER_HOST="{{ postgres_primary.host }}"
+PRIMARY_CLUSTER_PORT="{{ postgres_primary.port }}"
+PRIMARY_CLUSTER_USER="{{ postgres_primary.replication_user }}"
+PRIMARY_CLUSTER_PASSWORD="{{ postgres_primary.replication_password }}"
+{% if postgres_primary.replication_dbname is defined %}
+PRIMARY_CLUSTER_DBNAME=" dbname='{{ postgres_primary.replication_dbname }}'"
+{% endif %}
+
+read -p "You are about to clone the primary cluster (${PRIMARY_CLUSTER_HOST}:${PRIMARY_CLUSTER_PORT}) with pg_basebackup. This will replace the local ${CLUSTER_VERSION}/${CLUSTER_NAME} cluster. Are you sure? [y/n] " -r go
+
+if [ "$go" != "y" ]; then
+    echo "Aborted."
+    exit 1
+fi
+
+BACKUP_DATE=$(date +%s)
+
+echo "Stopping PostgreSQL"
+pg_ctlcluster "${CLUSTER_VERSION}" "${CLUSTER_NAME}" stop || true
+
+echo "Cleaning up old cluster directory"
+sudo -u postgres mv "/var/lib/postgresql/${CLUSTER_VERSION}/${CLUSTER_NAME}"{,"_${BACKUP_DATE}"}
+
+echo "Creating new directory"
+sudo -u postgres mkdir -p "/var/lib/postgresql/${CLUSTER_VERSION}/${CLUSTER_NAME}"
+
+echo "Get backup from primary server"
+sudo -u postgres \
+  time "/usr/lib/postgresql/${CLUSTER_VERSION}/bin/pg_basebackup" --format=p -R \
+  -d "host='${PRIMARY_CLUSTER_HOST}' port='${PRIMARY_CLUSTER_PORT}' user='${PRIMARY_CLUSTER_USER}' password='${PRIMARY_CLUSTER_PASSWORD}' ${PRIMARY_CLUSTER_DBNAME} sslmode=require" \
+  -D "/var/lib/postgresql/${CLUSTER_VERSION}/${CLUSTER_NAME}/"
+
+echo "Restoring .conf and server certificate"
+sudo -u postgres cp -a "/var/lib/postgresql/${CLUSTER_VERSION}/${CLUSTER_NAME}_${BACKUP_DATE}/"{*.conf,server.crt,server.key} "/var/lib/postgresql/${CLUSTER_VERSION}/${CLUSTER_NAME}/"
+
+echo "Ensure rights are correcly set"
+chown -R postgres:postgres "/var/lib/postgresql/${CLUSTER_VERSION}/"
+chmod 0700 "/var/lib/postgresql/${CLUSTER_VERSION}/"
+chmod -R o-rwx "/var/lib/postgresql/${CLUSTER_VERSION}/"
+
+echo "Starting PostgreSQL"
+sudo pg_ctlcluster "${CLUSTER_VERSION}" "${CLUSTER_NAME}" start