GKE-カスタム指標を使用するHPA-指標を取得できません
Google Cloud Monitoringにエクスポートされたカスタム指標があり、それに応じて展開をスケーリングしたいと思います。
これは私のHPAです。
apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
name: <DEPLOYMENT>-hpa
namespace: production
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: <DEPLOYMENT>
minReplicas: 5
maxReplicas: 100
metrics:
- type: External
external:
metricName: "custom.googleapis.com|rabbit_mq|test|messages_count"
metricSelector:
matchLabels:
metric.labels.name: production
targetValue: 1
私が見るhpaを説明するとき：
Warning FailedComputeMetricsReplicas 4m23s (x12 over 7m23s) horizontal-pod-autoscaler Invalid metrics (1 invalid out of 1), last error was: failed to get externa
l metric custom.googleapis.com|rabbit_mq|test|messages_count: unable to get external metric production/custom.googleapis.com|rabbit_mq|test|messages_count/&LabelSelect
or{MatchLabels:map[string]string{metric.labels.name: production,},MatchExpressions:[],}: unable to fetch metrics from external metrics API: the server is currently una
ble to handle the request (get custom.googleapis.com|rabbit_mq|test|messages_count.external.metrics.k8s.io)
Warning FailedGetExternalMetric 2m23s (x20 over 7m23s) horizontal-pod-autoscaler unable to get external metric production/custom.googleapis.com|rabbit_mq|te
st|messages_count/&LabelSelector{MatchLabels:map[string]string{metric.labels.name: production,},MatchExpressions:[],}: unable to fetch metrics from external metrics AP
I: the server is currently unable to handle the request (get custom.googleapis.com|rabbit_mq|test|messages_count.external.metrics.k8s.io)
そして：
Metrics: ( current / target )
"custom.googleapis.com|rabbit_mq|test|messages_count" (target value): <unknown> / 1
Kubernetesが指標を取得できません。
指標が利用可能であり、監視ダッシュボードを通じて更新されていることを確認しました。
クラスタノードにはStackdriver Monitoringのフルコントロールがあります： 
Kubernetesのバージョンは1.15です。
何が原因ですか？
編集1
Stackdriver-metadata-agent-cluster-levelデプロイメントがCrashLoopBackであることを発見しました。
kubectl -n=kube-system logs stackdriver-metadata-agent-cluster-le
vel-f8dcd8b45-nl8dj -c metadata-agent
コンテナからのログ：
vel-f8dcd8b45-nl8dj -c metadata-agent
I0408 11:50:41.999214 1 log_spam.go:42] Command line arguments:
I0408 11:50:41.999263 1 log_spam.go:44] argv[0]: '/k8s_metadata'
I0408 11:50:41.999271 1 log_spam.go:44] argv[1]: '-logtostderr'
I0408 11:50:41.999277 1 log_spam.go:44] argv[2]: '-v=1'
I0408 11:50:41.999284 1 log_spam.go:46] Process id 1
I0408 11:50:41.999311 1 log_spam.go:50] Current working directory /
I0408 11:50:41.999336 1 log_spam.go:52] Built on Jun 27 20:15:21 (1561666521)
at [email protected]:/google/src/files/255462966/depot/branches/gcm_k8s_metadata_release_branch/255450506.1/OVERLAY_READONLY/google3
as //cloud/monitoring/agents/k8s_metadata:k8s_metadata
with gc go1.12.5 for linux/AMD64
from changelist 255462966 with baseline 255450506 in a mint client based on //depot/branches/gcm_k8s_metadata_release_branch/255450506.1/google3
Build label: gcm_k8s_metadata_20190627a_RC00
Build tool: Blaze, release blaze-2019.06.17-2 (mainline @253503028)
Build target: //cloud/monitoring/agents/k8s_metadata:k8s_metadata
I0408 11:50:41.999641 1 trace.go:784] Starting tracingd dapper tracing
I0408 11:50:41.999785 1 trace.go:898] Failed loading config; disabling tracing: open /export/hda3/trace_data/trace_config.proto: no such file or directory
W0408 11:50:42.003682 1 client_config.go:549] Neither --kubeconfig nor --master was specified. Using the inClusterConfig. This might not work.
E0408 11:50:43.999995 1 main.go:110] Will only handle some server resources due to partial failure: unable to retrieve the complete list of server APIs: custom.m
etrics.k8s.io/v1beta1: the server is currently unable to handle the request, custom.metrics.k8s.io/v1beta2: the server is currently unable to handle the request, exter
nal.metrics.k8s.io/v1beta1: the server is currently unable to handle the request
I0408 11:50:44.000286 1 main.go:134] Initiating watch for { v1 nodes} resources
I0408 11:50:44.000394 1 main.go:134] Initiating watch for { v1 pods} resources
I0408 11:50:44.097181 1 main.go:134] Initiating watch for {batch v1beta1 cronjobs} resources
I0408 11:50:44.097488 1 main.go:134] Initiating watch for {apps v1 daemonsets} resources
I0408 11:50:44.098123 1 main.go:134] Initiating watch for {extensions v1beta1 daemonsets} resources
I0408 11:50:44.098427 1 main.go:134] Initiating watch for {apps v1 deployments} resources
I0408 11:50:44.098713 1 main.go:134] Initiating watch for {extensions v1beta1 deployments} resources
I0408 11:50:44.098919 1 main.go:134] Initiating watch for { v1 endpoints} resources
I0408 11:50:44.099134 1 main.go:134] Initiating watch for {extensions v1beta1 ingresses} resources
I0408 11:50:44.099207 1 main.go:134] Initiating watch for {batch v1 jobs} resources
I0408 11:50:44.099303 1 main.go:134] Initiating watch for { v1 namespaces} resources
I0408 11:50:44.099360 1 main.go:134] Initiating watch for {apps v1 replicasets} resources
I0408 11:50:44.099410 1 main.go:134] Initiating watch for {extensions v1beta1 replicasets} resources
I0408 11:50:44.099461 1 main.go:134] Initiating watch for { v1 replicationcontrollers} resources
I0408 11:50:44.197193 1 main.go:134] Initiating watch for { v1 services} resources
I0408 11:50:44.197348 1 main.go:134] Initiating watch for {apps v1 statefulsets} resources
I0408 11:50:44.197363 1 main.go:142] All resources are being watched, agent has started successfully
I0408 11:50:44.197374 1 main.go:145] No statusz port provided; not starting a server
I0408 11:50:45.197164 1 binarylog.go:95] Starting disk-based binary logging
I0408 11:50:45.197238 1 binarylog.go:265] rpc: flushed binary log to ""
編集2
編集1の問題は、次の回答を使用して修正されました https://stackoverflow.com/a/60549732/4869599
しかし、それでもhpaはメトリックをフェッチできません。
編集3
この問題は、CrashLoopBackでスタックしているcustom-metrics-stackdriver-adapter名前空間の下のcustom-metricsが原因であるようです。
マシンのログ：
E0419 13:36:48.036494 1 status.go:71] apiserver received an error that is not an metav1.Status: &errors.errorString{s:"http2: stream closed"}
E0419 13:36:48.832653 1 writers.go:172] apiserver was unable to write a JSON response: http2: stream closed
E0419 13:36:48.832692 1 status.go:71] apiserver received an error that is not an metav1.Status: &errors.errorString{s:"http2: stream closed"}
E0419 13:36:49.433150 1 writers.go:172] apiserver was unable to write a JSON response: http2: stream closed
E0419 13:36:49.433191 1 status.go:71] apiserver received an error that is not an metav1.Status: &errors.errorString{s:"http2: stream closed"}
E0419 13:36:51.032656 1 writers.go:172] apiserver was unable to write a JSON response: http2: stream closed
E0419 13:36:51.032694 1 status.go:71] apiserver received an error that is not an metav1.Status: &errors.errorString{s:"http2: stream closed"}
E0419 13:36:51.235248 1 writers.go:172] apiserver was unable to write a JSON response: http2: stream closed
関連する問題：
https://github.com/GoogleCloudPlatform/k8s-stackdriver/issues/3
kube-system名前空間で実行されているMetricsサーバーポッドを確認します。または、これを使用できます。
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: metrics-server
namespace: kube-system
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: metrics-server
namespace: kube-system
labels:
k8s-app: metrics-server
spec:
selector:
matchLabels:
k8s-app: metrics-server
template:
metadata:
name: metrics-server
labels:
k8s-app: metrics-server
spec:
serviceAccountName: metrics-server
volumes:
# mount in tmp so we can safely use from-scratch images and/or read-only containers
- name: tmp-dir
emptyDir: {}
containers:
- name: metrics-server
image: k8s.gcr.io/metrics-server-AMD64:v0.3.1
command:
- /metrics-server
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP
imagePullPolicy: Always
volumeMounts:
- name: tmp-dir
mountPath: /tmp