Clients that close their socket to nginx suddenly also cause nginx to close
its connection to uwsgi. When uwsgi finishes computing the response,
it thus tries to write to a closed socket, and generates either
IOError or SIGPIPE failures.
Since these are caused by the _client_ closing the connection
suddenly, they are not actionable by the server. At particularly high
volumes, this could represent some sort of server-side failure;
however, this is better detected by examining status codes at the
loadbalancer. nginx uses the error code 499 for this occurrence:
https://httpstatuses.com/499
Stop uwsgi from generating this family of exception entirely, using
configuration for uwsgi[1]; it documents these errors as "(annoying),"
hinting at their general utility."
[1] https://uwsgi-docs.readthedocs.io/en/latest/Options.html#ignore-sigpipe
Increasing the uwsgi listen backlog is intended to allow it to handle
higher connection rates during server restart, when many clients may
be trying to connect. The kernel, in turn, needs to have a
proportionally increased somaxconn soas to not refuse the connection.
Set somaxconn to 2x the uwsgi backlog, but no lower than the
default (128).
Prior to PostgreSQL 12, the `recovery_target_timeline` setting is only
valid in a `recovery.conf` file, as that file has its own
configuration parser. As such, including it in `postgresql.conf`
results in an error, and PostgreSQL will fail to start.
Remove the setting, reverting bff3b540b1. This fixes PostgreSQL 9.5,
9.6, 10, and 11; while the setting is not an error in a PostgreSQL 12
configuration file, it is unnecessary since `latest` is the default.
7d4a370a57 attempted to move the replication check to on the
PostgreSQL hosts. While it updated the _check_ to assume it was
running and talking to a local PostgreSQL instance, the configuration
and installation for the check were not updated. As such, the check
ran on the nagios host for each DB host, and produced no output.
Start distributing the check to all apopdb hosts, and configure nagios
to use the SSH tunnel to get there.
wal-g was used in `puppet/zulip` by env-wal-g, but only installed in
`puppet/zulip_ops`.
Merge all of the dependencies of doing backups using wal-g (wal-g
installation, the pg_backup_and_purge job, the nagios plugin that
verifies it happens) into a common base class in `puppet/zulip`, since
it is generally useful.
No plugins are installed inside the /usr/local/munin/lib this creates
in munin-node, nor are they symlinked into /etc/munin/plugins, so
non-default plugins are added by this.
The one complexity is that hosts_fullstack are treated differently, as
they are not currently found in the manual `hosts` list, and as such
do not get munin monitoring.
check_memcached does not support memcached authentication even in its
latest release (it’s in a TODO item comment, and that’s it), and was
never particularly useful.
When supervisor is first installed, it is started automatically, and
creates the socket, owned by root. Subsequent reconfiguration in
puppet only calls `reread + update`, which is insufficient to apply
the `chown = zulip:zulip` line in `supervisord.conf`, leaving the
socket owned by `root` and the last part of the installation unable to
restart `supervisor` services as the `zulip` user. The `chown` line
in `scripts/lib/install` exists to paper over this.
Add a separate exec target for changes to `supervisord.conf` itself,
which restarts the full service. This leaves the default `restart`
action on the service for the lightweight `reread + update` action,
which is more common.
We use `systemctl` only on redhat-esque builds, because CI runs
Ubuntu, but init is not systemd in that context. `systemctl reload`
is sufficient to re-apply the socket ownership, but a full `restart`
and not `reload` is necessary under `/etc/init.d/supervisor`.
wal-g has a slihghtly different format than wal-e in its `backup-list`
output; it only contains three columns:
- `name`
- `last_modified`,
- `wal_segment_backup_start`
..rather than wal-e's plethora, most of which were blank:
- `name`
- `last_modified`
- `expanded_size_bytes`
- `wal_segment_backup_start`
- `wal_segment_offset_backup_start`
- `wal_segment_backup_stop`
- `wal_segment_offset_backup_stop`
Remove one argument from the split.
In Bionic, nagios-plugins-basic is a transitional package which
depends on monitoring-plugins-basic. In Focal, it is a virtual
package, which means that every time puppet runs, it tries to
re-install the nagios-plugins-basic package.
Switch all instances to referring to `$zulip::common::nagios_plugins`,
and repoint that to monitoring-plugins-basic.
Frontend hosts in multiple-host configurations (including docker
hosts) need a `psql` binary installed. ca9d27175b switched to not
setting `postgresql.version` in `zulip.conf`, which in turn means that
`$zulip::base::postgres_version` is unset. This, in turn, led to the
frontend hosts installing `postgresql-client-`, whose trailing dash
causes apt to _uninstall_ that package.
Unconditionally install `postgresql-client` with no explicit version
attached. This is a metapackage which depends on the latest client
package, which currently means it will install `postgresql-client-12`.
On single-host installs which have configured `postgresql.version` in
`zulip.conf` to be a lower version, this will result in
`postgresql-client-12` existing alongside another
version (e.g. `postgresql-client-10`); `psql` will give the most
recent. This is acceptable because the semantic meaning of the
postgresql version in `zulip.conf` is about the database engine
itself, not the command-line client.
Support for Xenial and Stretch was removed (5154ddafca, 0f4b1076ad,
8944e0ad53, 79acd5ae40, 1219a2e854), but not all codepaths were
updated to remove their conditionals on it.
Remove all code predicated on Xenial or Stretch. debathena support
was migrated to Bionic, since that appears to be the current state of
existing debathena servers.
This prevents memcached from automatically appending the hostname to
the username, which was a source of problems on servers where the
hostname was changed.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
We would prefer to use the postgres packages from Postgres themselves,
if available. However, this requires ensures that, for existing
installs, we preserve the same version of postgres as their base
distribution installed.
Move the version-determination logic from being computed at puppet
interpolation time, to being computed at install time and pinned into
zulip.conf.
Since 9e8f1aacb3, zulip_ops machines
might have two Package declarations for `certbot`, which doesn't work
in puppet.
The fix is, as usual, to use our `zulip::safepackage` wrapper instead.
The style guide for Zulip is to always use "primary" and "replica"
when describing database replication. Adjust a few comments under
`puppet/` that do not adhere to this.
Unfortunately, some references still remain to the insensitive and
inaccurate "master" / "slave" terminology. However, these are only in
files which we are attempting to preserve as close to the upstream
versions they are derived from (e.g. postgresql.conf,
postfix/master.cf).
65774e1c4f switched from using the bundled check_postgres.pl to using
the version from packages; the file itself remained, however.
Remove it, and clean up references to it.
Fixes#15389.
Instead of SSH'ing around to them, run directly on the database hosts.
This means that the replicas do not know how many bytes behind they
are in _receiving_ the wall logs; thus, the monitoring also extends to
the primary database, which knows that information for each replica.
This also allows for detecting when there are too few active replicas.
Anders Kaseorg
Casper Kvan Clausen
Alex Vandiver
Tim Abbott
Mateusz Mandera