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.. _install:
Installing pg_auto_failover
===========================
We provide native system packages for pg_auto_failover on most popular Linux
distributions.
Use the steps below to install pg_auto_failover on PostgreSQL 11. At the
current time pg_auto_failover is compatible with both PostgreSQL 10 and
PostgreSQL 11.
Ubuntu or Debian
----------------
Postgres apt repository
~~~~~~~~~~~~~~~~~~~~~~~
Binary packages for debian and derivatives (ubuntu) are available from
`apt.postgresql.org`__ repository, install by following the linked
documentation and then::
$ sudo apt-get install pg-auto-failover-cli
$ sudo apt-get install postgresql-14-auto-failover
__ https://wiki.postgresql.org/wiki/Apt
The Postgres extension named "pgautofailover" is only necessary on the
monitor node. To install that extension, you can install the
``postgresql-14-auto-failover`` package when using Postgres 14. It's
available for other Postgres versions too.
Avoiding the default Postgres service
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When installing the debian Postgres package, the installation script will
initialize a Postgres data directory automatically, and register it to the
systemd services. When using pg_auto_failover, it is best to avoid that step.
To avoid automated creation of a Postgres data directory when installing the
debian package, follow those steps:
::
$ curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
$ echo "deb http://apt.postgresql.org/pub/repos/apt buster-pgdg main" > /etc/apt/sources.list.d/pgdg.list
# bypass initdb of a "main" cluster
$ echo 'create_main_cluster = false' | sudo tee -a /etc/postgresql-common/createcluster.conf
$ apt-get update
$ apt-get install -y --no-install-recommends postgresql-14
That way when it's time to :ref:`pg_autoctl_create_monitor` or
:ref:`pg_autoctl_create_postgres` there is no confusion about how to handle
the default Postgres service created by debian: it has not been created at
all.
Fedora, CentOS, or Red Hat
--------------------------
Quick install
~~~~~~~~~~~~~
The following installation method downloads a bash script that automates
several steps. The full script is available for review at our `package cloud
installation instructions page`__ url.
__ https://packagecloud.io/citusdata/community/install#bash
.. code-block:: bash
# add the required packages to your system
curl https://install.citusdata.com/community/rpm.sh | sudo bash
# install pg_auto_failover
sudo yum install -y pg-auto-failover14_12
# confirm installation
/usr/pgsql-12/bin/pg_autoctl --version
Manual installation
~~~~~~~~~~~~~~~~~~~
If you'd prefer to install your repo on your system manually, follow the
instructions from `package cloud manual installation`__ page. This page will
guide you with the specific details to achieve the 3 steps:
1. install the pygpgme yum-utils packages for your distribution
2. install a new RPM reposiroty for CitusData packages
3. update your local yum cache
Then when that's done, you can proceed with installing pg_auto_failover
itself as in the previous case:
.. code-block:: bash
# install pg_auto_failover
sudo yum install -y pg-auto-failover14_12
# confirm installation
/usr/pgsql-12/bin/pg_autoctl --version
__ https://packagecloud.io/citusdata/community/install#manual-rpm
Installing a pgautofailover Systemd unit
----------------------------------------
The command ``pg_autoctl show systemd`` outputs a systemd unit file that you
can use to setup a boot-time registered service for pg_auto_failover on your
machine.
Here's a sample output from the command:
.. code-block:: bash
$ export PGDATA=/var/lib/postgresql/monitor
$ pg_autoctl show systemd
13:44:34 INFO HINT: to complete a systemd integration, run the following commands:
13:44:34 INFO pg_autoctl -q show systemd --pgdata "/var/lib/postgresql/monitor" | sudo tee /etc/systemd/system/pgautofailover.service
13:44:34 INFO sudo systemctl daemon-reload
13:44:34 INFO sudo systemctl start pgautofailover
[Unit]
Description = pg_auto_failover
[Service]
WorkingDirectory = /var/lib/postgresql
Environment = 'PGDATA=/var/lib/postgresql/monitor'
User = postgres
ExecStart = /usr/lib/postgresql/10/bin/pg_autoctl run
Restart = always
StartLimitBurst = 0
[Install]
WantedBy = multi-user.target
Copy/pasting the commands given in the hint output from the command will
enable the pgautofailer service on your system, when using systemd.
It is important that PostgreSQL is started by ``pg_autoctl`` rather than by
systemd itself, as it might be that a failover has been done during a
reboot, for instance, and that once the reboot complete we want the local
Postgres to re-join as a secondary node where it used to be a primary node.
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