Add Kubernetes Worker and infrastructure
Adds Kubernetes Kubelet with patches for syscall-based mounting and
syscall-based (and much faster) metrics. fsquota patches have been
deferred to a further revision (for robust emptyDir capacity isolation).
Changes encoding of the node ID to hex since Base64-URL is not supported
as a character set for K8s names. Also adds `/etc/machine-id` and
`/etc/os-release` since Kubernetes wants them. `os-release` is generated
by stamping, `machine-id` is the hex-encoded node ID derived from the
public key.
Also includes a primitive reconciler which automatically ensures a set of
built-in Kubernetes objects are always present. Currently this includes
a PSP and some basic RBAC policies that are elementary to proper cluster
operations.
Adds an additional gRPC service (NodeDebugService) to cleanly
communicate with external debug and test tooling. It supports reading
from logbuffers for all externally-run components, checking conditions
(for replacing log matching in testing and debugging) and getting
debug credentials for the Kubernetes cluster.
A small utility (dbg) is provided that interfaces with NodeDebugService
and provides access to its functions from the CLI. It also incorporates
a kubectl wrapper which directly grabs credentials from the Debug API
and passes them to kubectl
(e.g. `bazel run //core/cmd/dbg -- kubectl describe node`).
Test Plan:
Manually tested.
Kubernetes:
`bazel run //core/cmd/dbg -- kubectl create -f test.yml`
Checked that pods run, logs are accessible and exec works.
Reading buffers:
`bazel run //core/cmd/dbg -- logs containerd`
Outputs containerd logs in the right order.
Automated testing is in the works, but has been deferred to a future
revision because this one is already too big again.
X-Origin-Diff: phab/D525
GitOrigin-RevId: 0fbfa0c433de405526c7f09ef10c466896331328
diff --git a/core/internal/kubernetes/kubelet.go b/core/internal/kubernetes/kubelet.go
new file mode 100644
index 0000000..b7d8157
--- /dev/null
+++ b/core/internal/kubernetes/kubelet.go
@@ -0,0 +1,141 @@
+// 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 kubernetes
+
+import (
+ "context"
+ "crypto/ed25519"
+ "encoding/json"
+ "encoding/pem"
+ "fmt"
+ "go.uber.org/zap"
+ "io/ioutil"
+ "os"
+ "os/exec"
+
+ "net"
+
+ "git.monogon.dev/source/nexantic.git/core/pkg/fileargs"
+ "go.etcd.io/etcd/clientv3"
+ v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+ "k8s.io/kubelet/config/v1beta1"
+)
+
+type KubeletSpec struct {
+ clusterDNS []net.IP
+}
+
+func bootstrapLocalKubelet(consensusKV clientv3.KV, nodeName string) error {
+ idCA, idKeyRaw, err := getCert(consensusKV, "id-ca")
+ if err != nil {
+ return err
+ }
+ idKey := ed25519.PrivateKey(idKeyRaw)
+ cert, key, err := issueCertificate(clientCertTemplate("system:node:"+nodeName, []string{"system:nodes"}), idCA, idKey)
+ if err != nil {
+ return err
+ }
+ kubeconfig, err := makeLocalKubeconfig(idCA, cert, key)
+ if err != nil {
+ return err
+ }
+
+ serverCert, serverKey, err := issueCertificate(serverCertTemplate([]string{nodeName}, []net.IP{}), idCA, idKey)
+ if err != nil {
+ return err
+ }
+ if err := os.MkdirAll("/data/kubernetes", 0755); err != nil {
+ return err
+ }
+ if err := ioutil.WriteFile("/data/kubernetes/kubelet.kubeconfig", kubeconfig, 0400); err != nil {
+ return err
+ }
+ if err := ioutil.WriteFile("/data/kubernetes/ca.crt", pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: idCA}), 0400); err != nil {
+ return err
+ }
+ if err := ioutil.WriteFile("/data/kubernetes/kubelet.crt", pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: serverCert}), 0400); err != nil {
+ return err
+ }
+ if err := ioutil.WriteFile("/data/kubernetes/kubelet.key", pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: serverKey}), 0400); err != nil {
+ return err
+ }
+
+ return nil
+}
+
+func (s *Service) runKubelet(ctx context.Context, spec *KubeletSpec) error {
+ fargs, err := fileargs.New()
+ if err != nil {
+ return err
+ }
+ var clusterDNS []string
+ for _, dnsIP := range spec.clusterDNS {
+ clusterDNS = append(clusterDNS, dnsIP.String())
+ }
+
+ kubeletConf := &v1beta1.KubeletConfiguration{
+ TypeMeta: v1.TypeMeta{
+ Kind: "KubeletConfiguration",
+ APIVersion: v1beta1.GroupName + "/v1beta1",
+ },
+ TLSCertFile: "/data/kubernetes/kubelet.crt",
+ TLSPrivateKeyFile: "/data/kubernetes/kubelet.key",
+ TLSMinVersion: "VersionTLS13",
+ ClusterDNS: clusterDNS,
+ Authentication: v1beta1.KubeletAuthentication{
+ X509: v1beta1.KubeletX509Authentication{
+ ClientCAFile: "/data/kubernetes/ca.crt",
+ },
+ },
+ ClusterDomain: "cluster.local",
+ EnableControllerAttachDetach: False(),
+ HairpinMode: "none",
+ MakeIPTablesUtilChains: False(), // We don't have iptables
+ FailSwapOn: False(), // Our kernel doesn't have swap enabled which breaks Kubelet's detection
+ KubeReserved: map[string]string{
+ "cpu": "200m",
+ "memory": "300Mi",
+ },
+ // We're not going to use this, but let's make it point to a known-empty directory in case anybody manages to
+ // trigger it.
+ VolumePluginDir: "/kubernetes/conf/flexvolume-plugins",
+ }
+
+ configRaw, err := json.Marshal(kubeletConf)
+ if err != nil {
+ return err
+ }
+ cmd := exec.CommandContext(ctx, "/kubernetes/bin/kube", "kubelet",
+ fargs.FileOpt("--config", "config.json", configRaw),
+ "--container-runtime=remote",
+ "--container-runtime-endpoint=unix:///containerd/run/containerd.sock",
+ "--kubeconfig=/data/kubernetes/kubelet.kubeconfig",
+ "--root-dir=/data/kubernetes/kubelet",
+ )
+ cmd.Env = []string{"PATH=/kubernetes/bin"}
+ cmd.Stdout = s.kubeletLogs
+ cmd.Stderr = s.kubeletLogs
+
+ err = cmd.Run()
+ fmt.Fprintf(s.kubeletLogs, "kubelet stopped: %v\n", err)
+ if ctx.Err() == context.Canceled {
+ s.logger.Info("kubelet stopped", zap.Error(err))
+ } else {
+ s.logger.Warn("kubelet stopped unexpectedly", zap.Error(err))
+ }
+ return err
+}