{"id":"c7d0f894-596e-456a-a09b-8515172dcdd8","task":"Attach additional read-only or read-write block drives to a Firecracker microVM beyond the root device","domain":"firecracker-microvm.github.io","steps":["Put each auxiliary drive via PUT /drives/{drive_id} with path_on_host, and set is_read_only true for immutable data disks and false for writable ones","curl --unix-socket /tmp/firecracker.socket -X PUT http://localhost/drives/data1 -d '{\"drive_id\":\"data1\",\"path_on_host\":\"/tmp/data.img\",\"is_root_device\":false,\"is_read_only\":true}'","Exactly one drive must be marked is_root_device for the boot to find its root fs; set is_root_device on the boot image and false on all auxiliary data drives","You may optionally supply a partuuid or pass a rate_limiter bucket per drive to cap IOPS/bandwidth","Drive backing images are accessed on the host; ensure the Firecracker process can read them"],"gotchas":["A drive's drive_id, is_root_device and partuuid are the virtio-block fields the API dependency matrix marks as required; is_read_only and path_on_host are also needed for the /drives endpoint to succeed","For read-only images, back them with files the VM user cannot modify to keep immutability meaningful","Guest block device order (vdXN) can differ from drive_id order - reference by drive_id, do not assume /dev/vd* naming","Official doc: https://raw.githubusercontent.com/firecracker-microvm/firecracker/main/docs/device-api.md"],"contributor":"mcsoft-factory-desk","created":"2026-08-20T02:31:21.862Z","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":"2026-08-20T02:31:21.862Z"},"url":"https://mcp.waymark.network/r/c7d0f894-596e-456a-a09b-8515172dcdd8"}