AMS High Availability (Technical Preview)

Ambari installs the Ambari Metrics System (AMS) , into the cluster with a single Metrics Collector component by default. The Collector is a daemon that runs on a specific host in the cluster and receives data from the registered publishers, the Monitors and Sinks. Depending on your needs, you might require AMS to have two Collectors to cover a High Availability scenario. This section describes the steps to enable AMS High Availability. The AMS high availability capability is Technical Preview.

Prerequisite

You must deploy AMS in distributed (not embedded) mode.

To provide AMS High Availability:

Steps

In Ambari Web, browse to the host where you would like to install another collector.
On the Host page, choose +Add.
Select Metrics Collector from the list.
Ambari installs the new Metrics Collector and configures Ambari Metrics for HA.
The new Collector will be installed in a “stopped” state.
In Ambari Web, will have to start the new Collector component from Ambari Web.

	Note
If you attempt to add a second Collector to the cluster without first switching AMS to distributed mode, the collector will install but will not be able to be started. Traceback (most recent call last): File "/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 150, in <module> AmsCollector().execute() File "/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py", line 313, in execute method(env) File "/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 48, in start self.configure(env, action = 'start') # for security File "/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py", line 116, in locking_configure original_configure(obj, args, kw) File "/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 42, in configure raise Fail("AMS in embedded mode cannot have more than 1 instance. Delete all but 1 instances or switch to Distributed mode ") resource_management.core.exceptions. Fail: AMS in embedded mode cannot have more than 1 instance. Delete all but 1 instances or switch to Distributed mode Workaround:* Delete the newly added Collector, enable distributed mode, then re-add the Collector.

Note

If you attempt to add a second Collector to the cluster without first switching AMS to distributed mode, the collector will install but will not be able to be started.

Traceback (most recent call last):
File 
 "/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 150, in <module>
 AmsCollector().execute()
File
 "/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py", line 313, in execute
 method(env)
File
"/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 48, in start self.configure(env, action = 'start') # for security
File
 "/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py", line 116, in locking_configure original_configure(obj, *args, **kw)
File
 "/var/lib/ambari-agent/cache/common-services/AMBARI_METRICS/0.1.0/package/scripts/metrics_collector.py", line 42, in configure raise
Fail("AMS in embedded mode cannot have more than 1 instance.
Delete all but 1 instances or switch to Distributed mode ") resource_management.core.exceptions.
Fail: AMS in embedded mode cannot have more than 1 instance.
Delete all but 1 instances or switch to Distributed mode

Workaround: Delete the newly added Collector, enable distributed mode, then re-add the Collector.

More Information

AMS Architecture

Customizing the Metrics Collector Mode

​AMS High Availability (Technical Preview)

AMS High Availability (Technical Preview)