core -> metropolis

Smalltown is now called Metropolis!

This is the first commit in a series of cleanup commits that prepare us
for an open source release. This one just some Bazel packages around to
follow a stricter directory layout.

All of Metropolis now lives in `//metropolis`.

All of Metropolis Node code now lives in `//metropolis/node`.

All of the main /init now lives in `//m/n/core`.

All of the Kubernetes functionality/glue now lives in `//m/n/kubernetes`.

Next steps:
     - hunt down all references to Smalltown and replace them appropriately
     - narrow down visibility rules
     - document new code organization
     - move `//build/toolchain` to `//monogon/build/toolchain`
     - do another cleanup pass between `//golibs` and
       `//monogon/node/{core,common}`.
     - remove `//delta` and `//anubis`

Fixes T799.

Test Plan: Just a very large refactor. CI should help us out here.

Bug: T799

X-Origin-Diff: phab/D667
GitOrigin-RevId: 6029b8d4edc42325d50042596b639e8b122d0ded
diff --git a/metropolis/node/kubernetes/containerd/BUILD.bazel b/metropolis/node/kubernetes/containerd/BUILD.bazel
new file mode 100644
index 0000000..9e42595
--- /dev/null
+++ b/metropolis/node/kubernetes/containerd/BUILD.bazel
@@ -0,0 +1,20 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["main.go"],
+    importpath = "git.monogon.dev/source/nexantic.git/metropolis/node/kubernetes/containerd",
+    visibility = ["//metropolis/node/core:__subpackages__"],
+    deps = [
+        "//metropolis/node/common/supervisor:go_default_library",
+        "//metropolis/node/core/localstorage:go_default_library",
+        "@com_github_containerd_containerd//:go_default_library",
+        "@com_github_containerd_containerd//namespaces:go_default_library",
+    ],
+)
+
+exports_files([
+    "config.toml",
+    "runsc.toml",
+    "cnispec.gojson",
+])
diff --git a/metropolis/node/kubernetes/containerd/cnispec.gojson b/metropolis/node/kubernetes/containerd/cnispec.gojson
new file mode 100644
index 0000000..0057036
--- /dev/null
+++ b/metropolis/node/kubernetes/containerd/cnispec.gojson
@@ -0,0 +1,29 @@
+{{- /*gotype: github.com/containerd/cri/pkg/server.cniConfigTemplate*/ -}}
+{
+    "name": "k8s-pod-network",
+    "cniVersion": "0.3.1",
+    "plugins": [
+        {
+            "type": "ptp",
+            "mtu": 1420,
+            "ipam": {
+                "type": "host-local",
+                "dataDir": "/containerd/run/ipam",
+                "ranges": [
+                    {{range $i, $range := .PodCIDRRanges}}{{if $i}},
+            {{end}}[
+            {
+                "subnet": "{{$range}}"
+            }
+        ]
+        {{end}}
+    ],
+    "routes": [
+        {{range $i, $route := .Routes}}{{if $i}},
+    {{end}}{
+    "dst": "{{$route}}"
+}{{end}}]
+}
+}
+]
+}
\ No newline at end of file
diff --git a/metropolis/node/kubernetes/containerd/config.toml b/metropolis/node/kubernetes/containerd/config.toml
new file mode 100644
index 0000000..f8c7fb1
--- /dev/null
+++ b/metropolis/node/kubernetes/containerd/config.toml
@@ -0,0 +1,125 @@
+version = 2
+root = "/data/containerd"
+state = "/ephemeral/containerd"
+plugin_dir = ""
+disabled_plugins = []
+required_plugins = []
+oom_score = 0
+
+[grpc]
+  address = "/ephemeral/containerd/client.sock"
+  tcp_address = ""
+  tcp_tls_cert = ""
+  tcp_tls_key = ""
+  uid = 0
+  gid = 0
+  max_recv_message_size = 16777216
+  max_send_message_size = 16777216
+
+[ttrpc]
+  address = ""
+  uid = 0
+  gid = 0
+
+[debug]
+  address = ""
+  uid = 0
+  gid = 0
+  level = ""
+
+[metrics]
+  address = ""
+  grpc_histogram = false
+
+[cgroup]
+  path = ""
+
+[timeouts]
+  "io.containerd.timeout.shim.cleanup" = "5s"
+  "io.containerd.timeout.shim.load" = "5s"
+  "io.containerd.timeout.shim.shutdown" = "3s"
+  "io.containerd.timeout.task.state" = "2s"
+
+[plugins]
+  [plugins."io.containerd.gc.v1.scheduler"]
+    pause_threshold = 0.02
+    deletion_threshold = 0
+    mutation_threshold = 100
+    schedule_delay = "0s"
+    startup_delay = "100ms"
+  [plugins."io.containerd.grpc.v1.cri"]
+    disable_tcp_service = true
+    stream_server_address = "127.0.0.1"
+    stream_server_port = "0"
+    stream_idle_timeout = "4h0m0s"
+    enable_selinux = false
+    sandbox_image = "k8s.gcr.io/pause:3.1"
+    stats_collect_period = 10
+    systemd_cgroup = false
+    enable_tls_streaming = false
+    ignore_image_defined_volumes = true
+    max_container_log_line_size = 16384
+    disable_cgroup = false
+    disable_apparmor = true
+    restrict_oom_score_adj = false
+    max_concurrent_downloads = 3
+    disable_proc_mount = false
+    [plugins."io.containerd.grpc.v1.cri".containerd]
+      snapshotter = "overlayfs"
+      default_runtime_name = "runsc"
+      no_pivot = false
+      [plugins."io.containerd.grpc.v1.cri".containerd.default_runtime]
+        runtime_type = ""
+        runtime_engine = ""
+        runtime_root = ""
+        privileged_without_host_devices = false
+      [plugins."io.containerd.grpc.v1.cri".containerd.untrusted_workload_runtime]
+        runtime_type = ""
+        runtime_engine = ""
+        runtime_root = ""
+        privileged_without_host_devices = false
+      [plugins."io.containerd.grpc.v1.cri".containerd.runtimes]
+        [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runsc]
+          runtime_type = "io.containerd.runsc.v1"
+          runtime_engine = ""
+          runtime_root = ""
+          privileged_without_host_devices = false
+          [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runsc.options]
+            TypeUrl = "io.containerd.runsc.v1.options"
+            ConfigPath = "/containerd/conf/runsc.toml"
+        [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
+          runtime_type = "io.containerd.runc.v2"
+          runtime_engine = ""
+          runtime_root = ""
+          privileged_without_host_devices = false
+          base_runtime_spec = ""
+    [plugins."io.containerd.grpc.v1.cri".cni]
+      bin_dir = "/containerd/bin/cni"
+      conf_dir = "/containerd/conf/cni"
+      max_conf_num = 0
+      conf_template = "/containerd/conf/cnispec.gojson"
+    [plugins."io.containerd.grpc.v1.cri".registry]
+      [plugins."io.containerd.grpc.v1.cri".registry.mirrors]
+        [plugins."io.containerd.grpc.v1.cri".registry.mirrors."docker.io"]
+          endpoint = ["https://registry-1.docker.io"]
+    [plugins."io.containerd.grpc.v1.cri".x509_key_pair_streaming]
+      tls_cert_file = ""
+      tls_key_file = ""
+  [plugins."io.containerd.internal.v1.opt"]
+    path = "/containerd/bin"
+  [plugins."io.containerd.internal.v1.restart"]
+    interval = "10s"
+  [plugins."io.containerd.metadata.v1.bolt"]
+    content_sharing_policy = "shared"
+  [plugins."io.containerd.monitor.v1.cgroups"]
+    no_prometheus = false
+  [plugins."io.containerd.runtime.v1.linux"]
+    shim = "containerd-shim"
+    runtime = "noop"
+    runtime_root = ""
+    no_shim = false
+    shim_debug = false
+  [plugins."io.containerd.runtime.v2.task"]
+    platforms = ["linux/amd64"]
+  [plugins."io.containerd.service.v1.diff-service"]
+    default = ["walking"]
\ No newline at end of file
diff --git a/metropolis/node/kubernetes/containerd/main.go b/metropolis/node/kubernetes/containerd/main.go
new file mode 100644
index 0000000..366f902
--- /dev/null
+++ b/metropolis/node/kubernetes/containerd/main.go
@@ -0,0 +1,146 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package containerd
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+
+	ctr "github.com/containerd/containerd"
+	"github.com/containerd/containerd/namespaces"
+
+	"git.monogon.dev/source/nexantic.git/metropolis/node/common/supervisor"
+	"git.monogon.dev/source/nexantic.git/metropolis/node/core/localstorage"
+)
+
+const (
+	preseedNamespacesDir = "/containerd/preseed/"
+)
+
+type Service struct {
+	EphemeralVolume *localstorage.EphemeralContainerdDirectory
+}
+
+func (s *Service) Run(ctx context.Context) error {
+	cmd := exec.CommandContext(ctx, "/containerd/bin/containerd", "--config", "/containerd/conf/config.toml")
+	cmd.Env = []string{"PATH=/containerd/bin", "TMPDIR=" + s.EphemeralVolume.Tmp.FullPath()}
+
+	runscFifo, err := os.OpenFile(s.EphemeralVolume.RunSCLogsFIFO.FullPath(), os.O_CREATE|os.O_RDONLY, os.ModeNamedPipe|0777)
+	if err != nil {
+		return err
+	}
+
+	if err := supervisor.Run(ctx, "runsc", s.logPump(runscFifo)); err != nil {
+		return fmt.Errorf("failed to start runsc log pump: %w", err)
+	}
+
+	if err := supervisor.Run(ctx, "preseed", s.runPreseed); err != nil {
+		return fmt.Errorf("failed to start preseed runnable: %w", err)
+	}
+	return supervisor.RunCommand(ctx, cmd)
+}
+
+// logPump returns a runnable that pipes data from a file/FIFO into its raw logger.
+// TODO(q3k): refactor this out to a generic function in supervisor or logtree.
+func (s *Service) logPump(fifo *os.File) supervisor.Runnable {
+	return func(ctx context.Context) error {
+		supervisor.Signal(ctx, supervisor.SignalHealthy)
+		for {
+			// Quit if requested.
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			default:
+			}
+
+			n, err := io.Copy(supervisor.RawLogger(ctx), fifo)
+			if n == 0 && err == nil {
+				// Hack because pipes/FIFOs can return zero reads when nobody is writing. To avoid busy-looping,
+				// sleep a bit before retrying. This does not loose data since the FIFO internal buffer will
+				// stall writes when it becomes full. 10ms maximum stall in a non-latency critical process (reading
+				// debug logs) is not an issue for us.
+				time.Sleep(10 * time.Millisecond)
+			} else if err != nil {
+				return fmt.Errorf("log pump failed: %v", err)
+			}
+		}
+	}
+}
+
+// runPreseed loads OCI bundles in tar form from preseedNamespacesDir into containerd at startup.
+// This can be run multiple times, containerd will automatically dedup the layers.
+// containerd uses namespaces to keep images (and everything else) separate so to define where the images will be loaded
+// to they need to be in a folder named after the namespace they should be loaded into.
+// containerd's CRI plugin (which is built as part of containerd) uses a hardcoded namespace ("k8s.io") for everything
+// accessed through CRI, so if an image should be available on K8s it needs to be in that namespace.
+// As an example if image helloworld should be loaded for use with Kubernetes, the OCI bundle needs to be at
+// <preseedNamespacesDir>/k8s.io/helloworld.tar. No tagging beyond what's in the bundle is performed.
+func (s *Service) runPreseed(ctx context.Context) error {
+	client, err := ctr.New(s.EphemeralVolume.ClientSocket.FullPath())
+	if err != nil {
+		return fmt.Errorf("failed to connect to containerd: %w", err)
+	}
+	logger := supervisor.Logger(ctx)
+	preseedNamespaceDirs, err := ioutil.ReadDir(preseedNamespacesDir)
+	if err != nil {
+		return fmt.Errorf("failed to open preseed dir: %w", err)
+	}
+	for _, dir := range preseedNamespaceDirs {
+		if !dir.IsDir() {
+			logger.Warningf("Non-Directory %q found in preseed folder, ignoring", dir.Name())
+			continue
+		}
+		namespace := dir.Name()
+		images, err := ioutil.ReadDir(filepath.Join(preseedNamespacesDir, namespace))
+		if err != nil {
+			return fmt.Errorf("failed to list namespace preseed directory for ns \"%v\": %w", namespace, err)
+		}
+		ctxWithNS := namespaces.WithNamespace(ctx, namespace)
+		for _, image := range images {
+			if image.IsDir() {
+				logger.Warningf("Directory %q found in preseed namespaced folder, ignoring", image.Name())
+				continue
+			}
+			imageFile, err := os.Open(filepath.Join(preseedNamespacesDir, namespace, image.Name()))
+			if err != nil {
+				return fmt.Errorf("failed to open preseed image \"%v\": %w", image.Name(), err)
+			}
+			// defer in this loop is fine since we're never going to preseed more than ~1M images which is where our
+			// file descriptor limit is.
+			defer imageFile.Close()
+			importedImages, err := client.Import(ctxWithNS, imageFile)
+			if err != nil {
+				return fmt.Errorf("failed to import preseed image: %w", err)
+			}
+			var importedImageNames []string
+			for _, img := range importedImages {
+				importedImageNames = append(importedImageNames, img.Name)
+			}
+			logger.Infof("Successfully imported preseeded bundle %s/%s into containerd", namespace, strings.Join(importedImageNames, ","))
+		}
+	}
+	supervisor.Signal(ctx, supervisor.SignalHealthy)
+	supervisor.Signal(ctx, supervisor.SignalDone)
+	return nil
+}
diff --git a/metropolis/node/kubernetes/containerd/runsc.toml b/metropolis/node/kubernetes/containerd/runsc.toml
new file mode 100644
index 0000000..4fe0751
--- /dev/null
+++ b/metropolis/node/kubernetes/containerd/runsc.toml
@@ -0,0 +1,6 @@
+root = "/ephemeral/containerd/runsc"
+[runsc_config]
+debug = "true"
+debug-log = "/ephemeral/containerd/runsc-logs.fifo"
+panic-log = "/ephemeral/containerd/runsc-logs.fifo"
+log = "/ephemeral/containerd/runsc-logs.fifo"