diff --git a/cloud/bmaas/bmdb/model/BUILD.bazel b/cloud/bmaas/bmdb/model/BUILD.bazel
new file mode 100644
index 0000000..7a0f122
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/BUILD.bazel
@@ -0,0 +1,28 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("//build/sqlc:sqlc.bzl", "sqlc_go_library")
+
+sqlc_go_library(
+    name = "sqlc_model",
+    dialect = "cockroachdb",
+    importpath = "source.monogon.dev/cloud/bmaas/bmdb/model",
+    migrations = glob(["migrations/*sql"]),
+    queries = [
+        "queries.sql",
+    ],
+)
+
+go_library(
+    name = "model",
+    srcs = ["migrations.go"],
+    embed = [
+        ":sqlc_model",  # keep
+    ],
+    embedsrcs = glob(["migrations/*sql"]),
+    importpath = "source.monogon.dev/cloud/bmaas/bmdb/model",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@com_github_golang_migrate_migrate_v4//source",
+        "@com_github_golang_migrate_migrate_v4//source/iofs",
+        "@com_github_google_uuid//:uuid",  # keep
+    ],
+)
diff --git a/cloud/bmaas/bmdb/model/migrations.go b/cloud/bmaas/bmdb/model/migrations.go
new file mode 100644
index 0000000..2c07768
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/migrations.go
@@ -0,0 +1,15 @@
+package model
+
+import (
+	"embed"
+
+	"github.com/golang-migrate/migrate/v4/source"
+	"github.com/golang-migrate/migrate/v4/source/iofs"
+)
+
+//go:embed migrations/*.sql
+var migrationData embed.FS
+
+func MigrationsSource() (source.Driver, error) {
+	return iofs.New(migrationData, "migrations")
+}
diff --git a/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql
new file mode 100644
index 0000000..6a85991
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql
@@ -0,0 +1,6 @@
+DROP TABLE machine_agent_report;
+DROP TABLE machine_agent_installed;
+DROP TABLE machine_provided;
+DROP TABLE work;
+DROP TABLE sessions;
+DROP TABLE machines;
diff --git a/cloud/bmaas/bmdb/model/migrations/1662136250_initial.up.sql b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.up.sql
new file mode 100644
index 0000000..b31324f
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.up.sql
@@ -0,0 +1,73 @@
+CREATE TABLE machines (
+    machine_id UUID NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    machine_created_at TIMESTAMPTZ NOT NULL
+);
+
+
+-- Sessions are maintained by components as they work on the rest of the machine
+-- database. Once a session is created, it must be maintained by its owning
+-- component by repeatedly 'poking' it, ie. updating the heartbeat_deadline
+-- value to be some point in the future.
+--
+-- TODO: garbage collect old sessions.
+CREATE TABLE sessions (
+    session_id UUID NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    -- Name of component which created this session. Human-readable.
+    session_component_name STRING NOT NULL,
+    -- Node name, hostname:port, pod name, whatever. Something to tell where
+    -- a particular component is running. Human-readable.
+    session_runtime_info STRING NOT NULL,
+    -- Time at which this session was created.
+    session_created_at TIMESTAMPTZ NOT NULL,
+    -- Number of seconds by which session_deadline (counting from now())
+    -- is bumped up every time the session is poked.
+    session_interval_seconds INT NOT NULL,
+    -- Deadline after which this session should not be considered valid anymore.
+    session_deadline TIMESTAMPTZ NOT NULL
+);
+
+CREATE TYPE process AS ENUM (
+    -- Reserved for unit tests.
+    'UnitTest1',
+    'UnitTest2'
+);
+
+-- Work items map a session to work performed on a machine. Multiple work items
+-- can exist per session, and thus, a session can back multiple items of work
+-- acting on multiple machines. These are optionally created by components to
+-- indicate some long-running process being performed on a machine, and will
+-- lock out the same process from being run simultaneously, eg. in a
+-- concurrently running instance of the same component.
+CREATE TABLE work (
+    -- Machine that this work is being performed on. Prevent deleting machines
+    -- that have active work on them.
+    machine_id UUID NOT NULL REFERENCES machines(machine_id) ON DELETE RESTRICT,
+    -- Session that this work item is tied to. If the session expires, so does
+    -- the work item.
+    session_id UUID NOT NULL REFERENCES sessions(session_id) ON DELETE CASCADE,
+    -- Human-readable process name.
+    process process NOT NULL,
+    UNIQUE (machine_id, process),
+    CONSTRAINT "primary" PRIMARY KEY (machine_id, session_id, process)
+);
+
+-- The following three tables are for illustrative purposes only.
+
+CREATE TABLE machine_provided (
+    machine_id UUID NOT NULL REFERENCES machines(machine_id) ON DELETE CASCADE,
+    provider STRING NOT NULL,
+    provider_id STRING NOT NULL,
+    CONSTRAINT "primary" PRIMARY KEY (machine_id)
+);
+
+CREATE TABLE machine_agent_installed (
+    machine_id UUID NOT NULL REFERENCES machines(machine_id) ON DELETE CASCADE,
+    CONSTRAINT "primary" PRIMARY KEY (machine_id)
+);
+
+CREATE TABLE machine_agent_report (
+    machine_id UUID NOT NULL REFERENCES machines(machine_id) ON DELETE CASCADE,
+    shape_cpu_count INT NOT NULL,
+    shape_memory_megabytes INT NOT NULL,
+    CONSTRAINT "primary" PRIMARY KEY (machine_id)
+);
diff --git a/cloud/bmaas/bmdb/model/queries.sql b/cloud/bmaas/bmdb/model/queries.sql
new file mode 100644
index 0000000..ee3f618
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/queries.sql
@@ -0,0 +1,64 @@
+-- name: NewMachine :one
+INSERT INTO machines (
+    machine_created_at
+) VALUES (
+    now()
+)
+RETURNING *;
+
+-- name: NewSession :one
+INSERT INTO sessions (
+    session_component_name, session_runtime_info, session_created_at, session_interval_seconds, session_deadline
+) VALUES (
+    $1, $2, now(), $3, (now() + $3 * interval '1 second')
+)
+RETURNING *;
+
+-- name: SessionPoke :exec
+-- Update a given session with a new deadline. Must be called in the same
+-- transaction as SessionCheck to ensure the session is still alive.
+UPDATE sessions
+SET session_deadline = now() + session_interval_seconds * interval '1 second'
+WHERE session_id = $1;
+
+-- name: SessionCheck :many
+-- SessionCheck returns a session by ID if that session is still valid (ie. its
+-- deadline hasn't expired).
+SELECT *
+FROM sessions
+WHERE session_id = $1
+AND session_deadline > now();
+
+-- name: StartWork :exec
+INSERT INTO work (
+    machine_id, session_id, process
+) VALUES (
+    $1, $2, $3
+);
+
+-- name: FinishWork :exec
+DELETE FROM work
+WHERE machine_id = $1
+  AND session_id = $2
+  AND process = $3;
+
+-- Example tag processing queries follow.
+
+-- name: MachineAddProvided :exec
+INSERT INTO machine_provided (
+    machine_id, provider, provider_id
+) VALUES (
+    $1, $2, $3
+);
+
+-- name: GetMachinesNeedingInstall :many
+SELECT
+    machine_provided.*
+FROM machines
+INNER JOIN machine_provided ON machines.machine_id = machine_provided.machine_id
+LEFT JOIN work ON machines.machine_id = work.machine_id AND work.process = 'NecromancerInstall'
+LEFT JOIN machine_agent_installed ON machines.machine_id = machine_agent_installed.machine_id
+WHERE machine_agent_installed.machine_id IS NULL
+  AND work.machine_id IS NULL
+LIMIT $1;
+