pg_autoctl perform promotion

pg_autoctl perform promotion - Perform a failover that promotes a target node

Synopsis

This command starts a Postgres failover orchestration from the pg_auto_promotion monitor and targets given node:

usage: pg_autoctl perform promotion  [ --pgdata --formation --group ]

--pgdata      path to data directory
--formation   formation to target, defaults to 'default'
--name        node name to target, defaults to current node
--wait        how many seconds to wait, default to 60

Description

The pg_auto_promotion monitor can be used to orchestrate a manual promotion, sometimes also known as a switchover. When doing so, split-brain are prevented thanks to intermediary states being used in the Finite State Machine.

The pg_autoctl perform promotion command waits until the promotion is known complete on the monitor, or until the hard-coded 60s timeout has passed.

The promotion orchestration is done in the background by the monitor, so even if the pg_autoctl perform promotion stops on the timeout, the promotion orchestration continues at the monitor.

Options

--pgdata

Location of the Postgres node being managed locally. Defaults to the environment variable PGDATA. Use --monitor to connect to a monitor from anywhere, rather than the monitor URI used by a local Postgres node managed with pg_autoctl.

--formation

Formation to target for the operation. Defaults to default.

--name

Name of the node that should be elected as the new primary node.

--wait

How many seconds to wait for notifications about the promotion. The command stops when the promotion is finished (a node is primary), or when the timeout has elapsed, whichever comes first. The value 0 (zero) disables the timeout and allows the command to wait forever.

Examples

$ pg_autoctl show state
 Name |  Node |      Host:Port |       LSN |   Connection |       Current State |      Assigned State
------+-------+----------------+-----------+--------------+---------------------+--------------------
node1 |     1 | localhost:5501 | 0/4000F88 |    read-only |           secondary |           secondary
node2 |     2 | localhost:5502 | 0/4000F88 |   read-write |             primary |             primary
node3 |     3 | localhost:5503 | 0/4000F88 |    read-only |           secondary |           secondary


$ pg_autoctl perform promotion --name node1
13:08:13 15297 INFO  Listening monitor notifications about state changes in formation "default" and group 0
13:08:13 15297 INFO  Following table displays times when notifications are received
    Time |  Name |  Node |      Host:Port |       Current State |      Assigned State
---------+-------+-------+----------------+---------------------+--------------------
13:08:13 | node1 |   0/1 | localhost:5501 |           secondary |           secondary
13:08:13 | node2 |   0/2 | localhost:5502 |             primary |            draining
13:08:13 | node2 |   0/2 | localhost:5502 |            draining |            draining
13:08:13 | node1 |   0/1 | localhost:5501 |           secondary |          report_lsn
13:08:13 | node3 |   0/3 | localhost:5503 |           secondary |          report_lsn
13:08:19 | node3 |   0/3 | localhost:5503 |          report_lsn |          report_lsn
13:08:19 | node1 |   0/1 | localhost:5501 |          report_lsn |          report_lsn
13:08:19 | node1 |   0/1 | localhost:5501 |          report_lsn |   prepare_promotion
13:08:19 | node1 |   0/1 | localhost:5501 |   prepare_promotion |   prepare_promotion
13:08:19 | node1 |   0/1 | localhost:5501 |   prepare_promotion |    stop_replication
13:08:19 | node2 |   0/2 | localhost:5502 |            draining |      demote_timeout
13:08:19 | node3 |   0/3 | localhost:5503 |          report_lsn |      join_secondary
13:08:19 | node2 |   0/2 | localhost:5502 |      demote_timeout |      demote_timeout
13:08:19 | node3 |   0/3 | localhost:5503 |      join_secondary |      join_secondary
13:08:20 | node1 |   0/1 | localhost:5501 |    stop_replication |    stop_replication
13:08:20 | node1 |   0/1 | localhost:5501 |    stop_replication |        wait_primary
13:08:20 | node2 |   0/2 | localhost:5502 |      demote_timeout |             demoted
13:08:20 | node1 |   0/1 | localhost:5501 |        wait_primary |        wait_primary
13:08:20 | node3 |   0/3 | localhost:5503 |      join_secondary |           secondary
13:08:20 | node2 |   0/2 | localhost:5502 |             demoted |             demoted
13:08:20 | node2 |   0/2 | localhost:5502 |             demoted |          catchingup
13:08:21 | node3 |   0/3 | localhost:5503 |           secondary |           secondary
13:08:21 | node1 |   0/1 | localhost:5501 |        wait_primary |             primary
13:08:21 | node2 |   0/2 | localhost:5502 |          catchingup |          catchingup
13:08:21 | node1 |   0/1 | localhost:5501 |             primary |             primary

$ pg_autoctl show state
 Name |  Node |      Host:Port |       LSN |   Connection |       Current State |      Assigned State
------+-------+----------------+-----------+--------------+---------------------+--------------------
node1 |     1 | localhost:5501 | 0/40012F0 |   read-write |             primary |             primary
node2 |     2 | localhost:5502 | 0/40012F0 |    read-only |           secondary |           secondary
node3 |     3 | localhost:5503 | 0/40012F0 |    read-only |           secondary |           secondary