pg_autoctl perform failover¶
pg_autoctl perform failover - Perform a failover for given formation and group
Synopsis¶
This command starts a Postgres failover orchestration from the pg_auto_failover monitor:
usage: pg_autoctl perform failover [ --pgdata --formation --group ]
--pgdata path to data directory
--formation formation to target, defaults to 'default'
--group group to target, defaults to 0
--wait how many seconds to wait, default to 60
Description¶
The pg_auto_failover monitor can be used to orchestrate a manual failover, 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 failover
command waits until the failover is
known complete on the monitor, or until the hard-coded 60s timeout has
passed.
The failover orchestration is done in the background by the monitor, so even
if the pg_autoctl perform failover
stops on the timeout, the failover
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 withpg_autoctl
.- --formation
Formation to target for the operation. Defaults to
default
.- --group
Postgres group to target for the operation. Defaults to
0
, only Citus formations may have more than one group.- --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.
Environment¶
PGDATA
Postgres directory location. Can be used instead of the
--pgdata
option.
PG_AUTOCTL_MONITOR
Postgres URI to connect to the monitor node, can be used instead of the
--monitor
option.
PGHOST, PGPORT, PGDATABASE, PGUSER, PGCONNECT_TIMEOUT, …
See the Postgres docs about Environment Variables for details.
TMPDIR
The pgcopydb command creates all its work files and directories in
${TMPDIR}/pgcopydb
, and defaults to/tmp/pgcopydb
.
XDG_CONFIG_HOME
The pg_autoctl command stores its configuration files in the standard place XDG_CONFIG_HOME. See the XDG Base Directory Specification.
XDG_DATA_HOME
The pg_autoctl command stores its internal states files in the standard place XDG_DATA_HOME, which defaults to
~/.local/share
. See the XDG Base Directory Specification.
Examples¶
$ pg_autoctl perform failover
12:57:30 3635 INFO Listening monitor notifications about state changes in formation "default" and group 0
12:57:30 3635 INFO Following table displays times when notifications are received
Time | Name | Node | Host:Port | Current State | Assigned State
---------+-------+-------+----------------+---------------------+--------------------
12:57:30 | node1 | 1 | localhost:5501 | primary | draining
12:57:30 | node1 | 1 | localhost:5501 | draining | draining
12:57:30 | node2 | 2 | localhost:5502 | secondary | report_lsn
12:57:30 | node3 | 3 | localhost:5503 | secondary | report_lsn
12:57:36 | node3 | 3 | localhost:5503 | report_lsn | report_lsn
12:57:36 | node2 | 2 | localhost:5502 | report_lsn | report_lsn
12:57:36 | node2 | 2 | localhost:5502 | report_lsn | prepare_promotion
12:57:36 | node2 | 2 | localhost:5502 | prepare_promotion | prepare_promotion
12:57:36 | node2 | 2 | localhost:5502 | prepare_promotion | stop_replication
12:57:36 | node1 | 1 | localhost:5501 | draining | demote_timeout
12:57:36 | node3 | 3 | localhost:5503 | report_lsn | join_secondary
12:57:36 | node1 | 1 | localhost:5501 | demote_timeout | demote_timeout
12:57:36 | node3 | 3 | localhost:5503 | join_secondary | join_secondary
12:57:37 | node2 | 2 | localhost:5502 | stop_replication | stop_replication
12:57:37 | node2 | 2 | localhost:5502 | stop_replication | wait_primary
12:57:37 | node1 | 1 | localhost:5501 | demote_timeout | demoted
12:57:37 | node1 | 1 | localhost:5501 | demoted | demoted
12:57:37 | node2 | 2 | localhost:5502 | wait_primary | wait_primary
12:57:37 | node3 | 3 | localhost:5503 | join_secondary | secondary
12:57:37 | node1 | 1 | localhost:5501 | demoted | catchingup
12:57:38 | node3 | 3 | localhost:5503 | secondary | secondary
12:57:38 | node2 | 2 | localhost:5502 | wait_primary | primary
12:57:38 | node1 | 1 | localhost:5501 | catchingup | catchingup
12:57:38 | node2 | 2 | localhost:5502 | primary | primary
$ pg_autoctl show state
Name | Node | Host:Port | LSN | Connection | Current State | Assigned State
------+-------+----------------+-----------+--------------+---------------------+--------------------
node1 | 1 | localhost:5501 | 0/4000F50 | read-only | secondary | secondary
node2 | 2 | localhost:5502 | 0/4000F50 | read-write | primary | primary
node3 | 3 | localhost:5503 | 0/4000F50 | read-only | secondary | secondary