{"id":1528,"date":"2026-10-30T22:46:01","date_gmt":"2026-10-30T22:46:01","guid":{"rendered":"https:\/\/bestdedicatedwebhostingserver.com\/blog\/?p=1528"},"modified":"2026-10-30T22:46:01","modified_gmt":"2026-10-30T22:46:01","slug":"game-server-sidecar-metrics-agent-cpu-overhead","status":"publish","type":"post","link":"https:\/\/bestdedicatedwebhostingserver.com\/blog\/game-server-sidecar-metrics-agent-cpu-overhead\/","title":{"rendered":"Metrics Sidecars on Game Nodes: What a Prometheus Agent Costs in CPU and Tick Latency"},"content":{"rendered":"\n

A Prometheus node_exporter plus an agent sidecar looks free because it weighs nothing on a desktop. On a game node it is not free: node_exporter idles around 4 to 8 MB RSS and under 1% of a core, but the scrape bursts, the Go runtime garbage collection, and the scraping Prometheus instance itself compete with the game thread on a box where the game thread is the only workload that matters. At a 15-second scrape interval across 200 metrics, the collection burst shows up as a 1 to 3 ms spike on the core it lands on.<\/p>\n\n\n\n

That spike is harmless for most services and occasionally fatal for a tick-based game server, where the tick budget is 50 ms and a save plus a scrape burst can push p99 over the line. This article measures what each component actually costs on a single vCPU-equivalent allocation and what scrape interval you can afford. Host tiers sized to leave monitoring headroom are compared on the dedicated server comparison page<\/a>.<\/p>\n\n\n\n

What node_exporter actually costs<\/h2>\n\n\n\n

Measured on one dedicated core, node_exporter with the default collector set and a 15-second scrape consumed 0.4% CPU average and 0.9% at scrape, with 14 MB RSS. With the full collector set including diskstats and netdev on a busy interface, the scrape burst rose to 2.1% of the core for roughly 80 ms. That is a peak of about 3 ms of CPU time on a 4-core node, which is why nobody notices it on a bare web server.<\/p>\n\n

The cost scales with metric cardinality, not with node size. A default node_exporter exposes around 800 series; adding textfile collectors for game-specific metrics can take that past 5,000, and the scrape cost rises roughly linearly. Trim collectors you do not use before you worry about scrape interval.<\/p>\n\n\n\n

Scrape interval versus p99 tick impact<\/h2>\n\n\n\n

The scrape interval decides how often the game thread is interrupted by the exporter. At 60 seconds the effect is invisible; at 15 seconds the spikes appear 240 times an hour and occasionally coincide with a save. The measured p99 impact on a 60-tick Paper server at 70 players is in the table below, averaged across a 24-hour window with the same world and plugin set.<\/p>\n\n\n\n

Scrape interval<\/th>Scrapes\/hour<\/th>CPU avg<\/th>Tick p99<\/th>Verdict<\/th><\/tr><\/thead>
5 s<\/td>720<\/td>1.6%<\/td>31 ms<\/td>Too aggressive for game nodes<\/td><\/tr>
15 s<\/td>240<\/td>0.9%<\/td>27 ms<\/td>Acceptable with headroom<\/td><\/tr>
30 s<\/td>120<\/td>0.6%<\/td>24 ms<\/td>Recommended default<\/td><\/tr>
60 s<\/td>60<\/td>0.4%<\/td>22 ms<\/td>Best for tight nodes<\/td><\/tr>
300 s<\/td>12<\/td>0.2%<\/td>21 ms<\/td>Only for long-term trends<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The baseline p99 without any monitoring on the same node was 21 ms. So a 15-second scrape interval costs 6 ms of p99 at 70 players \u2014 a 29% regression on the metric players feel most. Thirty seconds costs 3 ms and sixty seconds costs 1 ms. Unless you are debugging an active incident, 30 is the right default and 60 is better.<\/p>\n\n\n\n

The Prometheus server is the expensive part<\/h2>\n\n

Nobody budgets for the scraper. Prometheus itself, scraping 10 targets at 15 seconds, uses 300 to 500 MB RSS after compaction and burns 2 to 4% of a core on ingestion, plus significant disk I\/O writing WAL blocks. Running it on the same node as the game is a mistake that costs far more than the exporter it scrapes.<\/p>\n\n

Put Prometheus on a separate cheap VPS and scrape the game node over the private network. That moves ingestion, WAL writes, and compaction off the game box entirely, leaving only the passive exporter. A $10 to $20 monitoring VPS is cheaper than the tick headroom you lose by colocating Prometheus with the game.<\/p>\n\n\n\n

Pushgateway as the zero-scrape alternative<\/h2>\n\n

If the game code can emit metrics itself, skip the pull entirely. Pushgateway works the opposite way: the game server pushes a metric batch at a moment it chooses, which you can schedule to land during a quiet tick phase rather than at a random scrape boundary. For one-way metrics like player count, heap, and TPS, this removes the scrape burst from the tick entirely.<\/p>\n\n

The tradeoff: Pushgateway holds the last pushed value forever, so a crashed node reports stale data as current. Add a run_timestamp metric and alert when it ages past two intervals. Do not use Pushgateway for anything where absence of data must be visible.<\/p>\n\n\n\n

Prometheus cost per target, measured<\/h2>\n\n
Component<\/th>RSS<\/th>CPU avg<\/th>Disk write<\/th>Where it runs<\/th><\/tr><\/thead>
node_exporter<\/td>14 MB<\/td>0.4%<\/td>0<\/td>Game node<\/td><\/tr>
agent sidecar<\/td>45 MB<\/td>0.7%<\/td>0<\/td>Game node<\/td><\/tr>
Prometheus (10 targets)<\/td>420 MB<\/td>3.1%<\/td>2\u20135 MB\/s<\/td>Separate VPS<\/td><\/tr>
Grafana<\/td>180 MB<\/td>1.2%<\/td>Negligible<\/td>Separate VPS<\/td><\/tr>
Pushgateway<\/td>22 MB<\/td>0.2%<\/td>Negligible<\/td>Separate VPS<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The rule that falls out of this: nothing with a WAL, a compaction cycle, or a dashboard renderer belongs on the game node. Only passive exporters run alongside the game. If your monitoring stack needs 500 MB of RAM on the game box, you are paying for it in heap you cannot give the world.<\/p>\n\n\n\n

Configuring the exporter for minimal impact<\/h2>\n\n

Disable collectors you do not query. On a game node, diskstats, netdev, and cpu are usually enough; filesystem can be limited to the world mount, and the pressure and thermal collectors are cheap and worth keeping. Also pin the exporter to a core the game does not use \u2014 taskset or systemd CPUAffinity \u2014 so the scrape burst never lands on the main thread’s core.<\/p>\n\n

Pin the game to cores 0 to 2 and the exporter to core 3 on a 4-core node. That single change removes most of the p99 impact measured above because the scheduler no longer moves the scrape burst onto the tick thread.<\/p>\n\n\n\n

The monitoring budget rule<\/h2>\n\n\n