Cloud cost
Tag coverage
The share of spend, measured in dollars and not in resource count, that carries a required set of tags.
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Definition
Tag coverage asks a narrower question than "is this tagged?" Of the spend that could carry a tag, what share of the dollars does? The difference matters because untagged resources are rarely a random sample of the fleet. A few large resources, provisioned by hand, often make up a big share of untagged dollars. They can still be a small share of the untagged resource count.
A coverage number reported by resource count can look nearly complete. The dollar-weighted number can tell a very different story. So coverage you can trust is always weighted by cost.
Where it shows up
Tag coverage is a report built from the same billing export as any other cost breakdown. You filter it to a required tag key. Then you group spend by whether that key is present on each resource. Finally, you sum by dollar amount, not by a raw count of resources.
What makes it expensive
Do not trust a coverage number counted by resource. It can look nearly complete while a few large, hand-provisioned resources sit untagged. Those resources then dominate the untagged dollar total. Count-weighted and dollar-weighted coverage answer different questions. Only one of them is about money. Report the dollar-weighted one.
Related
More in Cloud cost
- Committed use discount (CUD)
- Reserved instance (RI)
- Savings plan (SP)
- On-demand vs. spot instances
- Data egress
- Amortized, blended, and unblended cost
- Billed vs. effective vs. list vs. contracted cost
- Rightsizing
- Idle and orphaned resources
- Storage class
- Lifecycle policy
- Incremental snapshot
- Allocatable capacity
- Requests vs. limits
- Cluster idle
- Workload idle
- Bin packing
- Cost allocation tags
- Unallocated spend
- Showback vs. chargeback
- Unit economics
- RI/SP coverage and utilization
- Observability tax
- Metric cardinality
- High-water-mark billing
- Log ingest vs. index
- Snowflake credit
- Auto-suspend / resume minimum
- BigQuery slot
- Bytes scanned & partition pruning
- Time Travel & Fail-safe
A total nobody owns, nobody fixes.
An unattributed cost stays unowned. CostMon assigns spend to an owner, so someone can act on it.