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AWS ElastiCache Sensor

AWS ELB Sensor allows monitoring of the performance of the AWS ElastiCache service.

This sensor offers good insight into ElastiCache performance using Amazon CloudWatch metrics. You set triggers for these metrics so that you can take corrective action before performance issues occur.

Requirements

This sensor requires sufficient rights to query data from the AWS API. In IAM (Identity and Access Management), you need to create policy with statements (JSON format):

[{
  "Sid": "Stmt1338559399560",
  "Action": [
      "elasticache:DescribeCacheClusters"
   ],
   "Effect": "Allow",
   "Resource": ""
},
{
   "Sid": "Stmt1338559372809",
   "Action": [
       "cloudwatch:GetMetricStatistics",
       "cloudwatch:GetMetricData",
       "cloudwatch:ListMetrics"
   ],
   "Effect": "Allow",
   "Resource": ""
}]

Options

This sensor requires credentials for AWS API. Select the region for which you want to monitor ElastiCache clusters.

Alerts
  • % Engine CPU Utilization > 90%
  • Database Memory Usage > 90%
  • Swap Usage > 50MB
  • More than 8000 new connections - We recommend that you determine your own alarm threshold for Current Connections and New Connections based on your application needs. An increasing number of CurrConnections might indicate a problem with your application; you will need to investigate the application behavior to address this issue.

Alerts are defined for all monitored ElastiCache clusters.

Performance Metrics

ElastiCache provides both host-level metrics and metrics that are specific to the cache engine software (Redis).

Selected host-level metrics:

  • Host\% CPU Utilization - The percentage of CPU utilization for the entire host
  • Host\Swap Usage [Bytes] - The amount of swap used on the host
  • Host\CPU Credit Usage - The number of CPU credits spent by the instance for CPU utilization
  • Network\Bytes In - The number of bytes the host has read from the network
  • Network\Bytes Out - The number of bytes sent out on all network interfaces by the instance

Selected metrics for Redis:

  • Redis\% Engine CPU Utilization - Provides access to the Redis process CPU utilization to gain better insights into your Redis workloads
  • Redis\% Database Memory Usage - The percentage of the memory available for the cluster that is in use
  • Redis\Current Connections - The number of client connections, excluding connections from read replicas
  • Redis\New Connections - The number of connections that have been accepted by the server
  • Redis\% Cache Hits - The number of successful read-only key lookups in the main dictionary
  • Redis\Cache Misses - The number of unsuccessful read-only key lookups in the main dictionary
  • Redis\Current Cache Items - The number of items in the cache
Reports (Data Collectors)

By default, the sensor collects data for two reports:

  • ElastiCache Host Report - containing Host\% CPU Utilization, Host\Swap Usage, Network\Bytes In, and Network\Bytes Out charts
  • ElastiCache Redis Report - containing Redis\% Engine CPU Utilization, Redis\% Database Memory Usage, Redis\Bytes Used For Cache, and Redis\Current Connections charts.

These metrics will be collected for all monitored ElastiCache clusters, and available as a report or through Performance Trend Viewer

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