puppet: Only install rabbitmq cron jobs via zulip_ops.

The rabbitmq cron jobs exist in order to call rabbitmqctl as root and
write the output to files that nagios can consume, since nagios is not
allowed to run rabbitmqctl.

In systems which do not have nagios configured, these every-minute
cron jobs add non-insignificant load, to no effect.  Move their
installation into `zulip_ops`.  In doing so, also combine the cron.d
files into a single file; this allows us to `ensure => absent` the old
filenames, removing them from existing systems.  Leave the resulting
combined cron.d file in `zulip`, since it is still of general utility
and note.

puppet/zulip/files/cron.d/rabbitmq-queuesize → puppet/zulip/files/cron.d/rabbitmq-monitoring

@@ -23,3 +23,4 @@
 SHELL=/bin/bash
 
 * * * * * root /home/zulip/deployments/current/scripts/nagios/check-rabbitmq-queue &> /var/lib/nagios_state/check-rabbitmq-results-tmp; mv /var/lib/nagios_state/check-rabbitmq-results-tmp /var/lib/nagios_state/check-rabbitmq-results
+* * * * * root /home/zulip/deployments/current/scripts/nagios/check-rabbitmq-consumers

puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_rabbitmq_consumers

@@ -6,7 +6,7 @@ Nagios plugin to check that the rabbitmq has the correct number of consumers.
 This script just checks the contents of /var/lib/nagios_state/check-rabbitmq-consumers,
 which is generated by scripts/nagios/check-rabbitmq-consumers.
 
-It is run by cron and can be found at puppet/zulip/files/cron.d/rabbitmq-numconsumers
+It is run by cron and can be found at puppet/zulip/files/cron.d/rabbitmq-monitoring
 """
 import sys
 

puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_rabbitmq_queues

@@ -7,7 +7,7 @@ of a stuck consumer.
 This script just checks the contents of /var/lib/nagios_state/check-rabbitmq-results,
 which is generated by scripts/nagios/check-rabbitmq-queue.
 
-It is run by cron; the crontab is in puppet/zulip/files/cron.d/rabbitmq-queuesize.
+It is run by cron; the crontab is in puppet/zulip/files/cron.d/rabbitmq-monitoring
 """
 import sys
 

puppet/zulip/manifests/rabbit.pp

@@ -9,21 +9,10 @@
                       ]
   package { $rabbit_packages: ensure => 'installed' }
 
-  file { '/etc/cron.d/rabbitmq-queuesize':
-    ensure  => file,
-    require => Package[rabbitmq-server],
-    owner   => 'root',
-    group   => 'root',
-    mode    => '0644',
-    source  => 'puppet:///modules/zulip/cron.d/rabbitmq-queuesize',
-  }
-  file { '/etc/cron.d/rabbitmq-numconsumers':
-    ensure  => file,
-    require => Package[rabbitmq-server],
-    owner   => 'root',
-    group   => 'root',
-    mode    => '0644',
-    source  => 'puppet:///modules/zulip/cron.d/rabbitmq-numconsumers',
+  # Removed 2020-09 in version 4.0; these lines can be removed in
+  # Zulip version 5.0 and later.
+  file { ['/etc/cron.d/rabbitmq-queuesize', '/etc/cron.d/rabbitmq-numconsumers']:
+    ensure => absent,
   }
 
   file { '/etc/default/rabbitmq-server':

puppet/zulip_ops/manifests/app_frontend.pp

@@ -80,4 +80,13 @@
     'zulip_send_receive_timing',
   ]
   zulip_ops::munin_plugin { $munin_plugins: }
+
+  file { '/etc/cron.d/rabbitmq-monitoring':
+    ensure  => file,
+    require => Package[rabbitmq-server],
+    owner   => 'root',
+    group   => 'root',
+    mode    => '0644',
+    source  => 'puppet:///modules/zulip/cron.d/rabbitmq-monitoring',
+  }
 }