Since Supervisor 4, which is installed on Ubuntu 20.04 and Debian 11,
`supervisorctl status` returns exit code 3 if any of the
supervisor-controlled processes are not running.
Using `supervisorctl status` as the Puppet `status` command for
Supervisor leads to unnecessarily trying to "start" a Supervisor
process which is already started, but happens to have one or more of
its managed processes stopped. This is an unnecessary no-op in
production environments, but in docker-init enviroments, such as in
CI, attempting to start the process a second time is an error.
Switch to checking if supervisor is running by way of sysv init. This
fixes the potential error in CI, as well as eliminates unnecessary
"starts" of supervisor when it was already running -- a situation
which made zulip-puppet-apply not idempotent:
```
root@alexmv-prod:~# supervisorctl status
process-fts-updates STOPPED Nov 10 12:33 AM
smokescreen RUNNING pid 1287280, uptime 0:35:32
zulip-django STOPPED Nov 10 12:33 AM
zulip-tornado STOPPED Nov 10 12:33 AM
[...]
root@alexmv-prod:~# ~zulip/deployments/current/scripts/zulip-puppet-apply --force
Notice: Compiled catalog for alexmv-prod.zulipdev.org in environment production in 2.32 seconds
Notice: /Stage[main]/Zulip::Supervisor/Service[supervisor]/ensure: ensure changed 'stopped' to 'running'
Notice: Applied catalog in 0.91 seconds
root@alexmv-prod:~# ~zulip/deployments/current/scripts/zulip-puppet-apply --force
Notice: Compiled catalog for alexmv-prod.zulipdev.org in environment production in 2.35 seconds
Notice: /Stage[main]/Zulip::Supervisor/Service[supervisor]/ensure: ensure changed 'stopped' to 'running'
Notice: Applied catalog in 0.92 seconds
```
In the series of migrations to this tool's configuration to support
specifying an arbitrary database name
(e.g. c17f502bb0), we broke support for
running process_fts_updates on the application server, connected to a
remote database server. That workflow is used by docker-zulip and
presumably other settings like Amazon RDS.
The fix is to import the Zulip virtualenv (if available) when running
on an application server. This is better than just supporting this
case, since both docker-zulip and an Amazon RDS database are setting
where it would be inconvenient to run process-fts-updates directly on
the database server. (In the former case, because we want to avoid
having a strong version dependency on the postgres container).
Details are available in this conversation:
https://chat.zulip.org/#narrow/stream/49-development-help/topic/Logic.20in.20process_fts_updates.20seems.20to.20be.20broken/near/1251894
Thanks to Erik Tews for reporting and help in debugging this issue.
We previously used `zulip-puppet-apply` with a custom config file,
with an updated PostgreSQL version but more limited set of
`puppet_classes`, to pre-create the basic settings for the new cluster
before running `pg_upgradecluster`.
Unfortunately, the supervisor config uses `purge => true` to remove
all SUPERVISOR configuration files that are not included in the puppet
configuration; this leads to it removing all other supervisor
processes during the upgrade, only to add them back and start them
during the second `zulip-puppet-apply`.
It also leads to `process-fts-updates` not being started after the
upgrade completes; this is the one supervisor config file which was
not removed and re-added, and thus the one that is not re-started due
to having been re-added. This was not detected in CI because CI added
a `start-server` command which was not in the upgrade documentation.
Set a custom facter fact that prevents the `purge` behaviour of the
supervisor configuration. We want to preserve that behaviour in
general, and using `zulip-puppet-apply` continues to be the best way
to pre-set-up the PostgreSQL configuration -- but we wish to avoid
that behaviour when we know we are applying a subset of the puppet
classes.
Since supervisor configs are no longer removed and re-added, this
requires an explicit start-server step in the instructions after the
upgrades complete. This brings the documentation into alignment with
what CI is testing.
These checks suffer from a couple notable problems:
- They are only enabled on staging hosts -- where they should never
be run. Since ef6d0ec5ca, these supervisor processes are only
run on one host, and never on the staging host.
- They run as the `nagios` user, which does not have appropriate
permissions, and thus the checks always fail. Specifically,
`nagios` does not have permissions to run `supervisorctl`, since
the socket is owned by the `zulip` user, and mode 0700; and the
`nagios` user does not have permission to access Zulip secrets to
run `./manage.py print_email_delivery_backlog`.
Rather than rewrite these checks to run on a cron as zulip, and check
those file contents as the nagios user, drop these checks -- they can
be rewritten at a later point, or replaced with Prometheus alerting,
and currently serve only to cause always-failing Nagios checks, which
normalizes alert failures.
Leave the files installed if they currently exist, rather than
cluttering puppet with `ensure => absent`; they do no harm if they are
left installed.
In an initial install, the following is a potential rule ordering:
```
Notice: /Stage[main]/Zulip::Supervisor/File[/etc/supervisor/conf.d/zulip]/ensure: created
Notice: /Stage[main]/Zulip::Supervisor/File[/etc/supervisor/supervisord.conf]/content: content changed '{md5}99dc7e8a1178ede9ae9794aaecbca436' to '{md5}7ef9771d2c476c246a3ebd95fab784cb'
Notice: /Stage[main]/Zulip::Supervisor/Exec[supervisor-restart]: Triggered 'refresh' from 1 event
[...]
Notice: /Stage[main]/Zulip::App_frontend_base/File[/etc/supervisor/conf.d/zulip/zulip.conf]/ensure: defined content as '{md5}d98ac8a974d44efb1d1bb2ef8b9c3dee'
[...]
Notice: /Stage[main]/Zulip::App_frontend_once/File[/etc/supervisor/conf.d/zulip/zulip-once.conf]/ensure: defined content as '{md5}53f56ae4b95413bfd7a117e3113082dc'
[...]
Notice: /Stage[main]/Zulip::Process_fts_updates/File[/etc/supervisor/conf.d/zulip/zulip_db.conf]/ensure: defined content as '{md5}96092d7f27d76f48178a53b51f80b0f0'
Notice: /Stage[main]/Zulip::Supervisor/Service[supervisor]/ensure: ensure changed 'stopped' to 'running'
```
The last line is misleading -- supervisor was already started by the
`supervisor-restart` process on the third line. As can be shown with
`zulip-puppet-apply --debug`, the last line just installs supervisor
to run on startup, using `systemctl`:
```
Debug: Executing: 'supervisorctl status'
Debug: Executing: '/usr/bin/systemctl unmask supervisor'
Debug: Executing: '/usr/bin/systemctl start supervisor'
```
This means the list of processes started by supervisor depends
entirely on which configuration files were successfully written out by
puppet before the initial `supervisor-restart` ran. Since
`zulip_db.conf` is written later than the rest, the initial install
often fails to start the `process-fts-updates` process. In this
state, an explicit `supervisorctl restart` or `supervisorctl reread &&
supervisorctl update` is required for the service to be found and
started.
Reorder the `supervisor-restart` exec to only run after the service is
started. Because all supervisor configuration files have a `notify`
of the service, this forces the ordering of:
```
(package) -> (config files) -> (service) -> (optional restart)
```
On first startup, this will start and them immediately restart
supervisor, which is unfortunate but unavoidable -- and not terribly
relevant, since the database will not have been created yet, and thus
most processes will be in a restart loop for failing to connect to it.
The sysvinit script for supervisor has a long-standing bug where
`/etc/init.d/supervisor restart` stops but does not then start the
supervisor process.
Work around this by making restart then try to start, and return if it
is currently running.
Not having the package installed will cause startup failures in
`process_fts_updates`; ensure that we've installed the package before
we potentially start the service.
93f62b999e removed the last file in
puppet/zulip/files/nagios_plugins/zulip_nagios_server, which means the
singular rule in zulip::nagios no longer applies cleanly.
Remove the `zulip::nagios` class, as it is no longer needed.
An organization with at most 5 users that is behind on payments isn't
worth spending time on investigating the situation.
For larger organizations, we likely want somewhat different logic that
at least does not void invoices.
Staging and other hosts that are `zulip::app_frontend_base` but not
`zulip::app_frontend_once` do not have a
/etc/supervisor/conf.d/zulip/zulip-once.conf and as such do not have
`zulip_deliver_scheduled_emails` or `zulip_deliver_scheduled_messages`
and thus supervisor will fail to reload.
Making the contents of `zulip-workers` contingent on if the server is
_also_ a `-once` server is complicated, and would involve using Concat
fragments, which severely limit readability.
Instead, expel those two from `zulip-workers`; this is somewhat
reasonable, since they are use an entirely different codepath from
zulip_events_*, using the database rather than RabbitMQ for their
queuing.
This is similar cleanup to 3ab9b31d2f, but only affects zulip_ops
services; it serves to ensure that any of these services which are no
longer enabled are automatically removed from supervisor.
Note that this will cause a supervisor restart on all affected hosts,
which will restart all supervisor services.
Failure to do this results in:
```
psql: error: failed to connect to `host=localhost user=zulip database=zulip`: failed to write startup message (x509: certificate is valid for [redacted], not localhost)
```
Host-based md5 auth for 127.0.0.1 must be removed from `pg_hba.conf`,
otherwise password authentication is preferred over certificate-based
authentication for localhost.
Nagios refuses to allow any modifications with use_authentication off;
re-enabled "authentication" but set a default user, which (by way of
the `*` permissions in 359f37389a) is allowed to take all actions.
This requires switching to a reverse tunnel for the auth connection,
with the side effect that the `zulip_ops::teleport::node` manifest can
be applied on servers anywhere in the Internet; they do not need to
have any publicly-available open ports.
This means that services will only open their ports if they are
actually run, without having to clutter rules.v4 with a log of `if`
statements.
This does not go as far as using `puppetlabs/firewall`[1] because that
would represent an additional DSL to learn; raw IPtables sections can
easily be inserted into the generated iptables file via
`concat::fragment` (either inline, or as a separate file), but config
can be centralized next to the appropriate service.
[1] https://forge.puppet.com/modules/puppetlabs/firewall
Alex Vandiver
Adam Benesh
Tim Abbott
Anders Kaseorg
Mateusz Mandera
Vishnu KS