Implemented some production steps

bin/database-wrangler/steps_production

@@ -43,19 +43,64 @@ function 005_forbid-writes-to-current-master(){
 }
 
 function 006_convert-azure-master-to-standby(){
-  return 0
+  ssh_remote "$AZURE_MASTER" $(cat << EOF
+    echo "
+standby_mode = 'on'
+recovery_target_timeline = 'latest'" > /var/lib/opt/gitlab/postgresql/data/recovery.conf
+    sudo chown postgres:postgres /var/lib/opt/gitlab/postgresql/data/recovery.conf
+    sudo chmod 600 /var/lib/opt/gitlab/postgresql/data/recovery.conf
+    sudo sv -W 1 stop /opt/gitlab/sv/postgres \
+      || (sudo sv int /opt/gitlab/sv/postgres \
+        && sudo sv -W 60 stop /opt/gitlab/sv/postgres)
+EOF
+)
 }
 
 function 007_check-gcp-nodes-has-same-azure-lsn(){
-  return 0
+  while true
+  do
+    azure_master_lsn="$(ssh_remote "$AZURE_MASTER" $(cat << EOF
+      cd /tmp;
+      sudo -u gitlab-psql gitlab-psql postgres \
+        -t -A -c "select case when pg_is_in_recovery() 
+          then pg_last_xlog_replay_location() 
+          else pg_current_xlog_location() end;";
+EOF
+      ))"
+    gcp_master_candidate_lsn="$(ssh_remote "$GCP_MASTER_CANDIDATE" $(cat << EOF
+      cd /tmp;
+      sudo -u gitlab-psql gitlab-psql postgres \
+        -t -A -c "select case when pg_is_in_recovery() 
+          then pg_last_xlog_replay_location() 
+          else pg_current_xlog_location() end;";
+EOF
+      ))"
+    if [ "$azure_master_lsn" == "$gcp_master_candidate_lsn" ]
+    then
+      echo "GCP and Azure have same LSN: $azure_master_lsn"
+      return 0
+    fi
+    echo "GCP and Azure have different LSN: Azure/$azure_master_lsn GCP/$gcp_master_candidate_lsn"
+    sleep 3
+  done
 }
 
 function 008_perform-gcp-candidate-master-promote(){
-  return 0
+  ssh_remote "$GCP_MASTER_CANDIDATE" $(cat << EOF
+    cd /tmp;
+    sudo -u gitlab-psql /opt/gitlab/embedded/bin/pg_ctl \
+      promote -D /var/lib/opt/gitlab/postgresql/data;
+EOF
+)
 }
 
 function 009_check-gcp-candidate-master-is-master(){
-  return 0
+  ssh_remote "$GCP_MASTER_CANDIDATE" $(cat << EOF
+    cd /tmp;
+    sudo -u gitlab-psql gitlab-psql postgres \
+      -t -A -c "select pg_is_in_recovery()";
+EOF
+) | grep -q 'f'
 }
 
 function 010_reduce-statement-timeout(){