# ElastiCache Reserved Node Opportunity

> ZopNight surfaces a 1-year ElastiCache Reserved Node purchase only for caches that look production, have at least 60 days of observed history with high uptime and utilization, are not already covered by a reservation or Savings Plan, and where the reserved rate times 730 hours beats current monthly spend.

Source: https://zop.dev/integrations/aws/recommendations/elasticache-reserved-node-opportunity
Updated: 2026-08-19

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## "Production" is decided on two axes

A 1-year Reserved Node is an irreversible commitment, so misclassifying a scratch
cluster is the expensive mistake. The rule reads two independent signals: the cache's
name and its environment tag. An explicit dev/test tag is an authoritative suppressor.
It wins even when the name says "prod". With no dev/test tag present, the cache must
look production either by name or by a production environment tag before the rule will
consider it at all. Ambiguous caches produce nothing.

## The bar for recommending a lock-in

Looking production is necessary, not sufficient. The cache must also prove it is a
commitment candidate: at least 60 days of observed history, high uptime across that
window, and meaningful CPU and memory utilization drawn from [the series ElastiCache publishes for each node](https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/CacheMetrics.html). A cache that runs part-time should
be scheduled instead, and an underutilized one should be rightsized. Locking either
into a 1-year reservation just cements the waste. Caches already covered by a
reservation or Savings Plan in the billing data are skipped outright, as is anything
the discoverer already marked reserved.

## Break-even math, not a discount table

The saving is computed as a real break-even. The Reserved Node is priced at its fixed
full-month rate (the reserved hourly rate multiplied by 730 hours) and recommended
only when that figure is lower than the cache's actual, uptime-adjusted monthly cost.
The saving is exactly the net difference, and the headline percentage is derived from
that same net. There is no fallback: when live reserved-node rates are unavailable the
rule abstains rather than applying [the roughly 40% average discount AWS lists for 1-year
partial-upfront reservations](https://aws.amazon.com/elasticache/pricing/). A reservation that would cost more than today's spend is
rejected by the same arithmetic.

## The full list of silent exits

No finding is produced for dev/test-tagged caches; caches that are neither
production-named nor production-tagged; caches already under a commitment; caches with
no resolved monthly cost; caches that fail the 60-day history, uptime or utilization
bar; and caches where reserved rates are missing or the break-even does not clear.

## Check your current reservations

```bash
aws elasticache describe-reserved-cache-nodes \
  --query "ReservedCacheNodes[?State=='active'].[ReservedCacheNodeId,CacheNodeType,CacheNodeCount,StartTime]" \
  --output table
```

Compare active node types and counts against your running clusters. Before buying,
confirm the cache will still exist in 12+ months. The reservation bills for its full
term whether the cluster survives or not, and it must match the node type it is meant
to cover.