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Aleksei Sviridkin
08c535c295
## What this PR does kube-apiserver's `/metrics` grows with the number of resources and CRDs, and on a full install it outgrows the 32MB `promscrape.maxScrapeSize` that monitoring-agents sets globally. vmagent then refuses every scrape of the API server, `up` drops to 0, and `KubeAPIDown` and `TargetDown` fire against a healthy control plane while every rule over API server metrics goes blind. The apiserver `VMServiceScrape` endpoint now sets its own `max_scrape_size` (128MB by default, `vmagent.apiserverMaxScrapeSize`). vmagent uses a per-job value in place of the global flag for that job only, so the 32MB guard for every other target is unchanged. The value stays finite on purpose: vmagent reads the whole uncompressed response into memory before parsing, `streamParse` included, so this limit is also a memory ceiling. A new `VMAgentScrapeSizeExceeded` warning fires on `vm_promscrape_max_scrape_size_exceeded_errors_total`, so an oversized target is reported as a size problem instead of only as a target that is down. The counter has no target label, so the description points at the vmagent targets page to find it. Upgrade note: the per-job value replaces the global flag in both directions. An install that raised `promscrape.maxScrapeSize` above 128MB through `vmagent.extraArgs` should raise `vmagent.apiserverMaxScrapeSize` as well. Verified on a dev cluster with the same operator (v0.68.4) and vmagent (v1.136.0): a test vmagent with a 1MB global limit scraped all three API servers with `max_scrape_size: 64MB` on the endpoint and refused all three without it. The new counter reached storage with the `namespace` and `pod` labels the alert uses, and the alert expression returned a series. The `VMRule` passes the operator's admission webhook, which rejects a malformed expression. Guest clusters get the same default, since their HelmRelease overrides other `vmagent` keys only. Fixes #4343 ### Screenshots Not a UI change. ### Downstream repositories - [x] No downstream repository is affected by this change - [ ] [cozystack/website](https://github.com/cozystack/website) - follow-up: - [ ] [cozystack/terraform-provider-cozystack](https://github.com/cozystack/terraform-provider-cozystack) - follow-up: - [ ] [cozystack/ansible-cozystack](https://github.com/cozystack/ansible-cozystack) - follow-up: - [ ] [cozystack/ccp](https://github.com/cozystack/ccp) - follow-up: - [ ] [cozystack/talm](https://github.com/cozystack/talm) - follow-up: - [ ] [cozystack/cozyhr](https://github.com/cozystack/cozyhr) - follow-up: - [ ] [cozystack/cozy-proxy](https://github.com/cozystack/cozy-proxy) - follow-up: - [ ] [cozystack/cozystack-telemetry-server](https://github.com/cozystack/cozystack-telemetry-server) - follow-up: - [ ] [cozystack/external-apps-example](https://github.com/cozystack/external-apps-example) - follow-up: - [ ] [cozystack/examples](https://github.com/cozystack/examples) - follow-up: - [ ] [cozystack/community](https://github.com/cozystack/community) - follow-up: ### Release note ```release-note fix(monitoring): kube-apiserver is scraped with its own 128MB size limit (`vmagent.apiserverMaxScrapeSize` in the monitoring-agents component) instead of the global 32MB, so a large `/metrics` no longer makes KubeAPIDown fire on a healthy API server. A new VMAgentScrapeSizeExceeded alert reports any target whose response exceeds the scrape size limit. ``` <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **New Features** * Kubernetes API server metrics can now use a configurable scrape-size limit, set to 128 MB by default. Leaving the setting empty uses the global limit. * **Bug Fixes** * Added a warning alert when vmagent reports scrape-size-limit errors. The alert identifies the affected vmagent pod and service and provides guidance for finding the target and adjusting its limit. <!-- end of auto-generated comment: release notes by coderabbit.ai -->