Monitoring: getting started
First, you need to install the metrics
package:
$ cd ${PROJECT_ROOT}
$ tarantoolctl rocks install metrics
Next, require it in your code:
local metrics = require('metrics')
Set a global label for your metrics:
metrics.set_global_labels({alias = 'alias'})
Enable default Tarantool metrics such as network, memory, operations, etc:
metrics.enable_default_metrics()
If you use Cartridge, enable Cartridge metrics:
metrics.enable_cartridge_metrics()
Initialize the Prometheus Exporter, or export metrics in any other format:
local httpd = require('http.server')
local http_handler = require('metrics.plugins.prometheus').collect_http
httpd.new('0.0.0.0', 8088)
:route({path = '/metrics'}, function(...)
return http_handler(...)
end)
:start()
box.cfg{
listen = 3302
}
Now you can use the HTTP API endpoint /metrics
to collect your metrics
in the Prometheus format. If you need your custom metrics, see the
API reference.
In production environments Tarantool Cluster usually has a large number of so called «routers», Tarantool instances that handle input load and it is required to evenly distribute the load. Various load-balancers are used for this, but any load-balancer have to know which «routers» are ready to accept the load at that very moment. Metrics library has a special plugin that creates an http handler that can be used by the load-balancer to check the current state of any Tarantool instance. If the instance is ready to accept the load, it will return a response with a 200 status code, if not, with a 500 status code.
cartridge.roles.metrics
is a role for
Tarantool Cartridge.
It allows using default metrics in a Cartridge application and manage them
via configuration.
Usage
Add
metrics
package to dependencies in the.rockspec
file. Make sure that you are using version 0.3.0 or higher.dependencies = { ... 'metrics >= 0.3.0-1', ... }
Make sure that you have
cartridge.roles.metrics
in the roles list incartridge.cfg
in your entry-point file (e.g.init.lua
).local ok, err = cartridge.cfg({ ... roles = { ... 'cartridge.roles.metrics', ... }, })
To view metrics via API endpoints, use
set_export
.NOTE that
set_export
has lower priority than clusterwide config and won’t work if metrics config is present.local metrics = require('cartridge.roles.metrics') metrics.set_export({ { path = '/path_for_json_metrics', format = 'json' }, { path = '/path_for_prometheus_metrics', format = 'prometheus' }, { path = '/health', format = 'health' } })
You can add several entry points of the same format by different paths, like this:
metrics.set_export({ { path = '/path_for_json_metrics', format = 'json' }, { path = '/another_path_for_json_metrics', format = 'json' }, })
The metrics will be available on the path specified in
path
in the format specified informat
.Enable role in the interface:
Since version 0.6.0 metrics role is permanent and enabled on instances by default.
After role initialization, default metrics will be enabled and the global label
'alias'
will be set. Note that'alias'
label value is set by instance configuration optionalias
orinstance_name
(since 0.6.1).If you need to use the functionality of any metrics package, you may get it as a Cartridge service and use it like a regular package after
require
:local cartridge = require('cartridge') local metrics = cartridge.service_get('metrics')
To change metrics HTTP path in runtime, you may use the following configuration (to learn more about Cartridge configuration, see this). We don’t recommend to use it to set up metrics role, use
set_export
instead.metrics: export: - path: '/path_for_json_metrics' format: 'json' - path: '/path_for_prometheus_metrics' format: 'prometheus' - path: '/health' format: 'health'