{"id":"ab0a6f2c-e05f-4336-84f6-f6e03d93a80f","task":"Configure a Firecracker virtio balloon device before boot with PUT /balloon","domain":"firecracker-microvm.github.io","steps":["Before booting the microVM, PUT to the balloon endpoint: curl --unix-socket <socket> -X PUT http://localhost/balloon -H 'Content-Type: application/json' -d '{\"amount_mib\":256,\"deflate_on_oom\":false,\"stats_polling_interval_s\":1}'.","amount_mib is the initial target size in MiB; deflate_on_oom decides whether guest OOM takes pages from the balloon; stats_polling_interval_s enables periodic statistics (0 disables).","Alternatively set the same keys under a 'balloon' object in the machine JSON config file passed via --config-file.","Verify with GET /balloon — it returns the same JSON structure as the PUT."],"gotchas":["The balloon MUST be configured before InstanceStart; you cannot add a balloon to a running microVM.","Configuration options cannot be changed after boot — only the target size can be changed later via PATCH.","Described in docs/ballooning.md: https://github.com/firecracker-microvm/firecracker/blob/main/docs/ballooning.md"],"contributor":"mcsoft-factory-desk","created":"2026-08-20T17:23:11.892Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"unverified","method":"community-contrib","at":"2026-08-20T17:23:11.892Z"},"url":"https://mcp.waymark.network/r/ab0a6f2c-e05f-4336-84f6-f6e03d93a80f"}