These values differed between the primary and secondary database
hosts, for unclear reasons. The differences date back to their
introduction in 387f63deaa. As the comment in the replica
confguration notes, settings of `vm.dirty_ratio = 10` and
`vm.dirty_background_ratio = 5` matched the kernel defaults for
"newer" kernels; however, kernel 2.6.30 bumped those to 20 and 10,
respectively[1], as a fix for underlying logic now being more correct.
Remove these overrides; they should at very least be consistent across
roles, and the previous values look to be an attempt to tune for a
very much older version of the Linux kernel, which was using an
different, buggier, algorithm under the hood.
[1] 1b5e62b42b
This file controls streaming replication, and recovery using wal-g on
the secondary. The `primary_conninfo` data needs to change on short
notice when database failover happens, in a way that is not suitable
for being controlled by puppet.
PostgreSQL 12, in fact, removes the use of the `recovery.conf` file[1];
the `primary_conninfo` and `restore_command` information goes into the
main `postgresql.conf` file, and the standby status is controlled by
the presence of absence of an empty `standby.signal` file.
Remove the puppet control of the `recovery.conf` file.
[1] https://pgstef.github.io/2018/11/26/postgresql12_preview_recovery_conf_disappears.html
Since the nagios authentication is stored _in the database_, it is
unnecessary to run if the database is simply a replica of the
production database. The only case in which this statement would have
an effect is if the postgres node contains a _different_ (or empty)
database, which `setup_disks` now effectively prevents.
Remove the unnecessary step.
The end state it produces is _either_:
- `/srv/postgresql` already existed, which was symlinked into
`/var/lib/postgresql`; postgres is left untouched. This is the
situation if `setup_disks` is run on the database primary, or a
replica which was correctly configured.
- An empty `/srv/postgresql` now exists, symlinked into
`/var/lib/postgresql`, and postgres is stopped. This is the
situation if `puppet` was just run on a new host, or a
previously-configured host was rebooted (clearing the temporary
disk in `/dev/nvme0`)
In the latter case, where `/srv/postgresql` is now empty, any previous
contents of `/var/lib/postgresql` are placed under `/root`,
timestamped for uniqueness.
In either case, the tool should now be idempotent.
Drop the change to move `/tmp` onto the local disk. Doing this move
confuses `resolved` until there is a restart, and has no clear
benefits. The change came in during bf82fadc95, but does not describe
the reasoning; it is particularly puzzling, since postgresql stores
its temporary files under `$PGDATA/base/pgsql_tmp`.
Do not RAID the disks together. This was previously done when they
were spinning media, for reliability; running them on an SSD obviates
this sufficiently. This means that updating the initramfs is also not
necessary.
In puppet/zulip_ops/files/postgresql/setup_disks.sh line 15:
array_name=$(mdadm --examine --scan | sed 's/.*name=//')
^-- SC2034: array_name appears unused. Verify use (or export if used externally).
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
The old zulip_ops Nagios configuration depended on Nagios having the
ability to login as the zulip user (with essentially full write
access); this configuration is helpful for limiting nagios to special
"nagios" user with more limited credentials.
There's no longer a reason to have copies of forked postgres
configuration files in our repository, since some time ago we merged
the features of these configuration files into the main
postgres_appdb_tuned.pp.
The old "zulip_internal" name was from back when Zulip, Inc. had two
distributions of Zulip, the enterprise distribution in puppet/zulip/
and the "internal" SAAS distribution in puppet/zulip_internal. I
think the name is a bit confusing in the new fully open-source Zulip
work, so we're replacing it with "zulip_ops". I don't think the new
name is perfect, but it's better.
In the following commits, we'll delete a bunch of pieces of Zulip,
Inc.'s infrastructure that don't exist anymore and thus are no longer
useful (e.g. the old Trac configuration), with the goal of cleaning
the repository of as much unnecessary content as possible.
Alex Vandiver
Anders Kaseorg
Alex Vandiver
rht
Anders Kaseorg
Tim Abbott
Tim Abbott