kubernetes集羣問題排查

時間 2019-12-20

標籤 kubernetes 集羣問題排查欄目負載均衡简体版

原文原文鏈接

1. 查看系統Event事件

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kubectl describe pod <PodName> --namespace=<NAMESPACE> java

該命令能夠顯示Pod建立時的配置定義、狀態等信息和最近的Event事件，事件信息可用於排錯。例如當Pod狀態爲Pending，可經過查看Event事件確認緣由，通常緣由有幾種：node

沒有可用的Node可調度nginx
開啓了資源配額管理而且當前Pod的目標節點上剛好沒有可用的資源web
正在下載鏡像（鏡像拉取耗時過久）或鏡像下載失敗。redis

kubectl describe還能夠查看其它k8s對象：NODE,RC,Service,Namespace,Secrets。docker

1.1. Pod

kubectl describe pod <PodName> --namespace=<NAMESPACE>api

如下是容器的啓動命令非阻塞式致使容器掛掉，被k8s頻繁重啓所產生的事件。
ruby

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kubectl describe pod --namespace=
Events:
FirstSeen LastSeen Count From SubobjectPath Reason Message
───────── ──────── ───── ──── ───────────── ────── ───────
7m 7m 1 {scheduler } Scheduled Successfully assigned yangsc-1-0-0-index0 to 10.8.216.19
7m 7m 1 {kubelet 10.8.216.19} containers{infra} Pulled Container image "registry.wae.haplat.net/kube-system/pause:0.8.0" already present on machine
7m 7m 1 {kubelet 10.8.216.19} containers{infra} Created Created with docker id 84f133c324d0
7m 7m 1 {kubelet 10.8.216.19} containers{infra} Started Started with docker id 84f133c324d0
7m 7m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 3f9f82abb145
7m 7m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 3f9f82abb145
7m 7m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id fb112e4002f4
7m 7m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id fb112e4002f4
6m 6m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 613b119d4474
6m 6m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 613b119d4474
6m 6m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 25cb68d1fd3d
6m 6m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 25cb68d1fd3d
5m 5m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 7d9ee8610b28
5m 5m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 7d9ee8610b28
3m 3m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 88b9e8d582dd
3m 3m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 88b9e8d582dd
7m 1m 7 {kubelet 10.8.216.19} containers{yangsc0} Pulling Pulling image "registry.ts.wae.haplat.net/test/tcp-hello:1.0.0"
1m 1m 1 {kubelet 10.8.216.19} containers{yangsc0} Started Started with docker id 089abff050e7
1m 1m 1 {kubelet 10.8.216.19} containers{yangsc0} Created Created with docker id 089abff050e7
7m 1m 7 {kubelet 10.8.216.19} containers{yangsc0} Pulled Successfully pulled image "registry.ts.wae.haplat.net/test/tcp-hello:1.0.0"
6m 7s 34 {kubelet 10.8.216.19} containers{yangsc0} Backoff Back-off restarting failed docker container

1.2. NODE

kubectl describe node 10.8.216.20

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[root@FC-43745A-10 ~]# kubectl describe node 10.8.216.20
Name: 10.8.216.20
Labels: kubernetes.io/hostname=10.8.216.20,namespace/bcs-cc=true,namespace/myview=true
CreationTimestamp: Mon, 17 Apr 2017 11:32:52 +0800
Phase:
Conditions:
Type Status LastHeartbeatTime LastTransitionTime Reason Message
──── ────── ───────────────── ────────────────── ────── ───────
Ready True Fri, 18 Aug 2017 09:38:33 +0800 Tue, 02 May 2017 17:40:58 +0800 KubeletReady kubelet is posting ready status
OutOfDisk False Fri, 18 Aug 2017 09:38:33 +0800 Mon, 17 Apr 2017 11:31:27 +0800 KubeletHasSufficientDisk kubelet has sufficient disk space available
Addresses: 10.8.216.20,10.8.216.20
Capacity:
cpu: 32
memory: 67323039744
pods: 40
System Info:
Machine ID: 723bafc7f6764022972b3eae1ce6b198
System UUID: 4C4C4544-0042-4210-8044-C3C04F595631
Boot ID: da01f2e3-987a-425a-9ca7-1caaec35d1e5
Kernel Version: 3.10.0-327.28.3.el7.x86_64
OS Image: CentOS Linux 7 (Core)
Container Runtime Version: docker://1.13.1
Kubelet Version: v1.1.1-wae2-13.1+79c90c68bfb72f-dirty
Kube-Proxy Version: v1.1.1-wae2-13.1+79c90c68bfb72f-dirty
ExternalID: 10.8.216.20
Non-terminated Pods: (6 in total)
Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits
───────── ──── ──────────── ────────── ─────────────── ─────────────
bcs-cc bcs-cc-api-0-0-1364-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
bcs-cc bcs-cc-api-0-0-1444-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
fw fw-demo2-0-0-1519-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
myview myview-api-0-0-1362-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
myview myview-api-0-0-1442-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
qa-ts-dna ts-dna-console3-0-0-1434-index0 1 (3%) 1 (3%) 4294967296 (6%) 4294967296 (6%)
Allocated resources:
(Total limits may be over 100%, i.e., overcommitted. More info: http://releases.k8s.io/HEAD/docs/user-guide/compute-resources.md)
CPU Requests CPU Limits Memory Requests Memory Limits
──────────── ────────── ─────────────── ─────────────
6 (18%) 6 (18%) 25769803776 (38%) 25769803776 (38%)
No events.

1.3. RC

kubectl describe rc mytest-1-0-0 --namespace=test

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[root@FC-43745A-10 ~]# kubectl describe rc mytest-1-0-0 --namespace=test
Name: mytest-1-0-0
Namespace: test
Image(s): registry.ts.wae.haplat.net/test/mywebcalculator:1.0.1
Selector: app=mytest,appVersion=1.0.0
Labels: app=mytest,appVersion=1.0.0,env=ts,zone=inner
Replicas: 1 current / 1 desired
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
No volumes.
Events:
FirstSeen LastSeen Count From SubobjectPath Reason Message
───────── ──────── ───── ──── ───────────── ────── ───────
20h 19h 9 {replication-controller } FailedCreate Error creating: Pod "mytest-1-0-0-index0" is forbidden: limited to 10 pods
20h 17h 7 {replication-controller } FailedCreate Error creating: pods "mytest-1-0-0-index0" already exists
20h 17h 4 {replication-controller } SuccessfulCreate Created pod: mytest-1-0-0-index0

1.4. NAMESPACE

kubectl describe namespace test

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[root@FC-43745A-10 ~]# kubectl describe namespace test
Name: test
Labels: <none>
Status: Active
Resource Quotas
Resource Used Hard
--- --- ---
cpu 5 20
memory 1342177280 53687091200
persistentvolumeclaims 0 10
pods 4 10
replicationcontrollers 8 20
resourcequotas 1 1
secrets 3 10
services 8 20
No resource limits.

1.5. Service

kubectl describe service wae-containers-1-1-0 --namespace=test

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[root@FC-43745A-10 ~]# kubectl describe service wae-containers-1-1-0 --namespace=test
Name: wae-containers-1-1-0
Namespace: test
Labels: app=wae-containers,appVersion=1.1.0,env=ts,zone=inner
Selector: app=wae-containers,appVersion=1.1.0
Type: ClusterIP
IP: 10.254.46.42
Port: port-dna-tcp-35913 35913/TCP
Endpoints: 10.0.92.17:35913
Port: port-l7-tcp-8080 8080/TCP
Endpoints: 10.0.92.17:8080
Session Affinity: None
No events.

2. 查看容器日誌

一、查看指定pod的日誌

kubectl logs <pod_name>

kubectl logs -f <pod_name> #相似tail -f的方式查看

二、查看上一個pod的日誌

kubectl logs -p <pod_name>

三、查看指定pod中指定容器的日誌

kubectl logs <pod_name> -c <container_name>

四、kubectl logs的更多使用請參考kubectl logs --help

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[root@node5 ~]# kubectl logs --help
Print the logs for a container in a pod. If the pod has only one container, the container name is optional.
Usage:
kubectl logs [-f] [-p] POD [-c CONTAINER] [flags]
Aliases:
logs, log
Examples:
# Return snapshot logs from pod nginx with only one container
$ kubectl logs nginx
# Return snapshot of previous terminated ruby container logs from pod web-1
$ kubectl logs -p -c ruby web-1
# Begin streaming the logs of the ruby container in pod web-1
$ kubectl logs -f -c ruby web-1
# Display only the most recent 20 lines of output in pod nginx
$ kubectl logs --tail=20 nginx
# Show all logs from pod nginx written in the last hour
$ kubectl logs --since=1h nginx

五、docker logs

若是有Node機器（即宿主機）的登陸權限，能夠到出問題的pod所調度到的機器上，經過docker logs的命令查看對應容器的問題緣由。

例如：

docker ps -a |grep <container>

docker logs <container_id>

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[root@kube-master ~]# docker ps -a |grep redis
ee7398bba500 docker.io/redis@sha256:bb47379e6e0101441dbb1fe585171521e4ee2ebe1ae23f663232f56ac41551de "docker-entrypoint.sh" About a minute ago Exited (1) About a minute ago k8s_kubernetes-log-tail-bigdatalog-testappkey_test-add-plugins-403621826-bskfz_test-7da2c1_a5412774-d43f-11e7-98c3-a2642aaa3458_6
5360d15344fb docker.io/redis@sha256:bb47379e6e0101441dbb1fe585171521e4ee2ebe1ae23f663232f56ac41551de "docker-entrypoint.sh" 7 minutes ago Up 7 minutes k8s_kubernetes-log-tail-testagent_test-add-plugins-403621826-bskfz_test-7da2c1_a5412774-d43f-11e7-98c3-a2642aaa3458_0
[root@kube-master ~]#
[root@kube-master ~]# docker logs ee7398bba500
1:C 28 Nov 13:32:29.352 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 28 Nov 13:32:29.354 # Redis version=4.0.6, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 28 Nov 13:32:29.354 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
1:M 28 Nov 13:32:29.355 # Creating Server TCP listening socket *:6379: bind: Address already in use

以上報錯是由於端口衝突問題：bind: Address already in use

3. 查看k8s服務日誌

3.1. journalctl

在Linux系統上systemd系統來管理kubernetes服務，而且journal系統會接管服務程序的輸出日誌，能夠經過systemctl status <xxx>或journalctl -u <xxx> -f來查看kubernetes服務的日誌。

其中kubernetes組件包括：

k8s組件	涉及日誌內容	備註
kube-apiserver
kube-controller-manager	Pod擴容相關或RC相關
kube-scheduler	Pod擴容相關或RC相關
kubelet	Pod生命週期相關：建立、中止等
etcd