写在前面
- 学习
K8s，所以整理记忆 - 文章由
《Kubernetes权威指南:从Docker到Kubernetes实践全接触》读书学习整理而来
「 一切时代的艺术都在努力为我们内心那神圣的无声的欲望提供语言。 ——赫尔曼·黑塞《彼得·卡门青》」
❝「因为没有具体的Demo，所以文章有些空，类似于一些指导思想，读着乏味，这里先列出干货：一些查问题的网站，关于内容之后有机会在补充相关的案例，如果解决问题，时间紧张的小伙伴还是针对问题描述下面的平台里找找」 ❞
查问题的网站 |
|---|
Kubernetes官网中监控、记录和调试相关问题: https://kubernetes.io/docs/tasks/debug-application-cluster/ |
Kubernetes官方论坛: https://discuss.kubernetes.io/(这个需要科学上网) |
GitHub库关于Kubernetes问题列表:https://github.com/kubernetes/kubernetes/issues |
StackOverflow网站上关于Kubernetes的问题讨论：https://stackoverflow.com/questions/tagged/kubernetes |
Kubernetes Slack聊天群组: https://kubernetes.slack.com/(需要谷歌账号) |
Kubernetes集群中常见问题的排查方法
为了跟踪和发现在Kubernetes集群中运行的容器应用出现的问题,我们常用如下查错方法。
查看Kubernetes对象的当前运行时信息,特别是与对象关联的Event事件。这些事件记录了相关主题、发生时间、最近发生时间、发生次数及事件原因等,对排查故障非常有价值。通过查看对象的运行时数据,我们还可以发现参数错误、关联错误、状态异常等明显问题。由于在Kubernetes中多种对象相互关联,因此这一步可能会涉及多·个相关对象的排查问题。
对于服务、容器方面的问题,可能需要深入容器内部进行故障诊断,此时可以通过查看容器的运行日志来定位具体问题。
对于某些复杂问题,例如Pod调度这种全局性的问题,可能需要结合集群中每个节点上的Kubernetes服务日志来排查。比如搜集Master上的kube-apiserver, kube-schedule, kube-controler-manager服务日志,以及各个Node上的kubelet, kube-proxy服务日志.
「查看系统Event」
在Kubernetes集群中创建Pod后,我们可以通过kubectl get pods命令查看Pod列表,但通过该命令显示的信息有限。Kubernetes提供了kubectl describe pod命令来查看一个Pod的详细信息,例如:
通过kubectl describe pod命令,可以显示Pod创建时的配置定义、状态等信息,还可以显示与该Pod相关的最近的Event事件,事件信息对于查错非常有用。
「如果某个Pod一直处于Pending状态,我们就可以通过kubectl describe了解具体的原因：」
- 没有可用的
Node以供调度，可能原因为pod端口冲突，或者受Taints影响，。 - 开启了
资源配额管理，但在当前调度的目标节点上资源不足。 镜像下载失败等。
「查看pod详细信息」
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl describe pods etcd-vms81.liruilongs.github.io -n kube-system
# pod创建的基本信息
Name: etcd-vms81.liruilongs.github.io
Namespace: kube-system
Priority: 2000001000
Priority Class Name: system-node-critical
Node: vms81.liruilongs.github.io/192.168.26.81
Start Time: Tue, 25 Jan 2022 21:54:20 0800
Labels: component=etcd
tier=control-plane
Annotations: kubeadm.kubernetes.io/etcd.advertise-client-urls: https://192.168.26.81:2379
kubernetes.io/config.hash: 1502584f9ab841720212d4341d723ba2
kubernetes.io/config.mirror: 1502584f9ab841720212d4341d723ba2
kubernetes.io/config.seen: 2021-12-13T00:01:04.834825537 08:00
kubernetes.io/config.source: file
seccomp.security.alpha.kubernetes.io/pod: runtime/default
Status: Running # Node当前的运行状态,
IP: 192.168.26.81
IPs:
IP: 192.168.26.81
Controlled By: Node/vms81.liruilongs.github.io
Containers:
etcd: # pod的一些基础信息
Container ID: docker://20d99a98a4c2590e8726916932790200ba1cf93c48f3c84ca1298ffdcaa4f28a
Image: registry.aliyuncs.com/google_containers/etcd:3.5.0-0
Image ID: docker-pullable://registry.aliyuncs.com/google_containers/etcd@sha256:9ce33ba33d8e738a5b85ed50b5080ac746deceed4a7496c550927a7a19ca3b6d
Port: <none>
Host Port: <none>
Command: # 容器运行的一些启动参数
etcd
--advertise-client-urls=https://192.168.26.81:2379
--cert-file=/etc/kubernetes/pki/etcd/server.crt
--client-cert-auth=true
--data-dir=/var/lib/etcd
--initial-advertise-peer-urls=https://192.168.26.81:2380
--initial-cluster=vms81.liruilongs.github.io=https://192.168.26.81:2380
--key-file=/etc/kubernetes/pki/etcd/server.key
--listen-client-urls=https://127.0.0.1:2379,https://192.168.26.81:2379
--listen-metrics-urls=http://127.0.0.1:2381
--listen-peer-urls=https://192.168.26.81:2380
--name=vms81.liruilongs.github.io
--peer-cert-file=/etc/kubernetes/pki/etcd/peer.crt
--peer-client-cert-auth=true
--peer-key-file=/etc/kubernetes/pki/etcd/peer.key
--peer-trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt
--snapshot-count=10000
--trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt
State: Running
Started: Tue, 25 Jan 2022 21:54:20 0800
Last State: Terminated
Reason: Error
Exit Code: 255
Started: Mon, 24 Jan 2022 08:35:16 0800
Finished: Tue, 25 Jan 2022 21:53:56 0800
Ready: True
Restart Count: 128
Requests: # 涉及到的一些资源信息
cpu: 100m
memory: 100Mi
Liveness: http-get http://127.0.0.1:2381/health delay=10s timeout=15s period=10s #success=1 #failure=8
Startup: http-get http://127.0.0.1:2381/health delay=10s timeout=15s period=10s #success=1 #failure=24
Environment: <none>
Mounts:
/etc/kubernetes/pki/etcd from etcd-certs (rw)
/var/lib/etcd from etcd-data (rw)
Conditions: #pod启动以后会做一系列的自检工作:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes: # 映射的宿主机的数据卷信息，这里的定义为宿主机共享
etcd-certs:
Type: HostPath (bare host directory volume)
Path: /etc/kubernetes/pki/etcd
HostPathType: DirectoryOrCreate
etcd-data:
Type: HostPath (bare host directory volume)
Path: /var/lib/etcd
HostPathType: DirectoryOrCreate
QoS Class: Burstable
Node-Selectors: <none>
Tolerations: :NoExecute op=Exists
Events: <none>
┌──[root@vms81.liruilongs.github.io]-[~]
└─$
「查看集群中的Node节点和节点的详细信息」
[root@liruilong k8s]# kubectl get nodes
NAME STATUS AGE
127.0.0.1 Ready 2d
[root@liruilong k8s]# kubectl describe node 127.0.0.1
# Node基本信息:名称、标签、创建时间等。
Name: 127.0.0.1
Role:
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/hostname=127.0.0.1
Taints: <none>
CreationTimestamp: Fri, 27 Aug 2021 00:07:09 0800
Phase:
# Node当前的运行状态, Node启动以后会做一系列的自检工作:
# 比如磁盘是否满了,如果满了就标注OutODisk=True
# 否则继续检查内存是否不足(如果内存不足,就标注MemoryPressure=True)
# 最后一切正常,就设置为Ready状态(Ready=True)
# 该状态表示Node处于健康状态, Master将可以在其上调度新的任务了(如启动Pod)
Conditions:
Type Status LastHeartbeatTime LastTransitionTime Reason Message
---- ------ ----------------- ------------------ ------ -------
OutOfDisk False Sun, 29 Aug 2021 23:05:53 0800 Sat, 28 Aug 2021 00:30:35 0800 KubeletHasSufficientDisk kubelet has sufficient disk space available
MemoryPressure False Sun, 29 Aug 2021 23:05:53 0800 Fri, 27 Aug 2021 00:07:09 0800 KubeletHasSufficientMemory kubelet has sufficient memory available
DiskPressure False Sun, 29 Aug 2021 23:05:53 0800 Fri, 27 Aug 2021 00:07:09 0800 KubeletHasNoDiskPressure kubelet has no disk pressure
Ready True Sun, 29 Aug 2021 23:05:53 0800 Sat, 28 Aug 2021 00:30:35 0800 KubeletReady kubelet is posting ready status
# Node的主机地址与主机名。
Addresses: 127.0.0.1,127.0.0.1,127.0.0.1
# Node上的资源总量:描述Node可用的系统资源,包括CPU、内存数量、最大可调度Pod数量等,注意到目前Kubernetes已经实验性地支持GPU资源分配了(alpha.kubernetes.io/nvidia-gpu=0)
Capacity:
alpha.kubernetes.io/nvidia-gpu: 0
cpu: 1
memory: 1882012Ki
pods: 110
# Node可分配资源量:描述Node当前可用于分配的资源量。
Allocatable:
alpha.kubernetes.io/nvidia-gpu: 0
cpu: 1
memory: 1882012Ki
pods: 110
# 主机系统信息:包括主机的唯一标识UUID, Linux kernel版本号、操作系统类型与版本、Kubernetes版本号、kubelet与kube-proxy的版本号等。
System Info:
Machine ID: 963c2c41b08343f7b063dddac6b2e486
System UUID: EB90EDC4-404C-410B-800F-3C65816C0E2D
Boot ID: 4a9349b0-ce4b-4b4a-8766-c5c4256bb80b
Kernel Version: 3.10.0-1160.15.2.el7.x86_64
OS Image: CentOS Linux 7 (Core)
Operating System: linux
Architecture: amd64
Container Runtime Version: docker://1.13.1
Kubelet Version: v1.5.2
Kube-Proxy Version: v1.5.2
ExternalID: 127.0.0.1
# 当前正在运行的Pod列表概要信息
Non-terminated Pods: (3 in total)
Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits
--------- ---- ------------ ---------- --------------- -------------
default mysql-2cpt9 0 (0%) 0 (0%) 0 (0%) 0 (0%)
default myweb-53r32 0 (0%) 0 (0%) 0 (0%) 0 (0%)
default myweb-609w4 0 (0%) 0 (0%) 0 (0%) 0 (0%)
# 已分配的资源使用概要信息,例如资源申请的最低、最大允许使用量占系统总量的百分比。
Allocated resources:
(Total limits may be over 100 percent, i.e., overcommitted.
CPU Requests CPU Limits Memory Requests Memory Limits
------------ ---------- --------------- -------------
0 (0%) 0 (0%) 0 (0%) 0 (0%)
# Node相关的Event信息。
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
4h 27m 3 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. pod: "myweb-609w4_default(01d719dd-08b1-11ec-9d6a-00163e1220cb)". Falling back to DNSDefault policy.
25m 25m 1 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. pod: "mysql-2cpt9_default(1c9353ba-08d7-11ec-9d6a-00163e1220cb)". Falling back to DNSDefault policy.
查看容器日志
在需要排查容器内部应用程序生成的日志时，我们可以使用kubectl logs <pod_name>命令
这里打印etcd数据库的日志信息,查看日志中异常的相关信息,这里用过过滤error关键字的方法来查看相关的信息
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl logs etcd-vms81.liruilongs.github.io -n kube-system | grep -i error | head -5
{"level":"info","ts":"2022-01-25T13:54:33.191Z","caller":"wal/repair.go:96","msg":"repaired","path":"/var/lib/etcd/member/wal/0000000000000014-0000000000185aba.wal","error":"unexpected EOF"}
{"level":"info","ts":"2022-01-25T13:54:33.192Z","caller":"etcdserver/storage.go:109","msg":"repaired WAL","error":"unexpected EOF"}
{"level":"warn","ts":"2022-01-25T13:54:33.884Z","caller":"embed/config_logging.go:169","msg":"rejected connection","remote-addr":"127.0.0.1:53950","server-name":"","error":"EOF"}
{"level":"warn","ts":"2022-01-25T13:54:33.885Z","caller":"embed/config_logging.go:169","msg":"rejected connection","remote-addr":"127.0.0.1:53948","server-name":"","error":"EOF"}
{"level":"warn","ts":"2022-01-28T03:00:37.549Z","caller":"etcdserver/util.go:166","msg":"apply request took too long","took":"628.230855ms","expected-duration":"100ms","prefix":"read-only range ","request":"key:"/registry/runtimeclasses/" range_end:"/registry/runtimeclasses0" count_only:true ","response":"","error":"context canceled"}
┌──[root@vms81.liruilongs.github.io]-[~]
└─$
查看Kubernetes服务日志
如果在Linux系统上安装Kubernetes,并且使用systemd系统管理Kubernetes服务,那么systemd的journal系统会接管服务程序的输出日志。在这种环境中,可以通过使用systemd status或journalct具来查看系统服务的日志。例如:
查看服务服务启动的相关信息，通过这个，可以定位服务加载的配置文件信息，启动参数配置情况
┌──[root@vms81.liruilongs.github.io]-[~]
└─$systemctl status kubelet.service -l
● kubelet.service - kubelet: The Kubernetes Node Agent
Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled)
Drop-In: /usr/lib/systemd/system/kubelet.service.d
└─10-kubeadm.conf
Active: active (running) since 二 2022-01-25 21:53:35 CST; 6 days ago
Docs: https://kubernetes.io/docs/
Main PID: 1014 (kubelet)
Memory: 208.2M
CGroup: /system.slice/kubelet.service
└─1014 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.5
2月 01 17:47:14 vms81.liruilongs.github.io kubelet[1014]: W0201 17:47:14.258523 1014 container.go:586] Failed to update stats for container "/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pode1b874bfdef201d69db10b200b8f47d5.slice/docker-c20fa960cfebd38172e123a5d87ecd499518bf22381f7aaa62d57131e7eb1aae.scope": unable to determine device info for dir: /var/lib/docker/overlay2/07d7695f2c479fbd0b654016345fcbacd0838276fb57f8291f993ed6799fae8d/diff: stat failed on /var/lib/docker/overlay2/07d7695f2c479fbd0b654016345fcbacd0838276fb57f8291f993ed6799fae8d/diff with error: no such file or directory, continuing to push stats
。。。。。。。。。。
通过 journalct来查看相关的服务日志信息，查看当前用户下的kubelet服务日志中有error关键字的字段的报错问题
┌──[root@vms81.liruilongs.github.io]-[~]
└─$journalctl -u kubelet.service | grep -i error | head -2
1月 25 21:53:55 vms81.liruilongs.github.io kubelet[1014]: I0125 21:53:55.865441 1014 docker_service.go:264] "Docker Info" dockerInfo=&{ID:HN3K:C6LG:QGV7:N2CG:VELF:CJ6T:HFR5:EEKH:HLPO:CDEU:GN3E:QAJJ Containers:32 ContainersRunning:11 ContainersPaused:0 ContainersStopped:21 Images:32 Driver:overlay2 DriverStatus:[[Backing Filesystem xfs] [Supports d_type true] [Native Overlay Diff true] [userxattr false]] SystemStatus:[] Plugins:{Volume:[local] Network:[bridge host ipvlan macvlan null overlay] Authorization:[] Log:[awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog]} MemoryLimit:true SwapLimit:true KernelMemory:true KernelMemoryTCP:true CPUCfsPeriod:true CPUCfsQuota:true CPUShares:true CPUSet:true PidsLimit:true IPv4Forwarding:true BridgeNfIptables:true BridgeNfIP6tables:true Debug:false NFd:26 OomKillDisable:true NGoroutines:39 SystemTime:2022-01-25T21:53:55.833509372 08:00 LoggingDriver:json-file CgroupDriver:systemd CgroupVersion:1 NEventsListener:0 KernelVersion:3.10.0-693.el7.x86_64 OperatingSystem:CentOS Linux 7 (Core) OSVersion:7 OSType:linux Architecture:x86_64 IndexServerAddress:https://index.docker.io/v1/ RegistryConfig:0xc000a8f960 NCPU:2 MemTotal:4126896128 GenericResources:[] DockerRootDir:/var/lib/docker HTTPProxy: HTTPSProxy: NoProxy: Name:vms81.liruilongs.github.io Labels:[] ExperimentalBuild:false ServerVersion:20.10.9 ClusterStore: ClusterAdvertise: Runtimes:map[io.containerd.runc.v2:{Path:runc Args:[] Shim:<nil>} io.containerd.runtime.v1.linux:{Path:runc Args:[] Shim:<nil>} runc:{Path:runc Args:[] Shim:<nil>}] DefaultRuntime:runc Swarm:{NodeID: NodeAddr: LocalNodeState:inactive ControlAvailable:false Error: RemoteManagers:[] Nodes:0 Managers:0 Cluster:<nil> Warnings:[]} LiveRestoreEnabled:false Isolation: InitBinary:docker-init ContainerdCommit:{ID:5b46e404f6b9f661a205e28d59c982d3634148f8 Expected:5b46e404f6b9f661a205e28d59c982d3634148f8} RuncCommit:{ID:v1.0.2-0-g52b36a2 Expected:v1.0.2-0-g52b36a2} InitCommit:{ID:de40ad0 Expected:de40ad0} SecurityOptions:[name=seccomp,profile=default] ProductLicense: DefaultAddressPools:[]
1月 25 21:53:56 vms81.liruilongs.github.io kubelet[1014]: E0125 21:53:56.293100 1014 controller.go:144] failed to ensure lease exists, will retry in 200ms, error: Get "https://192.168.26.81:6443/apis/coordination.k8s.io/v1/namespaces/kube-node-lease/leases/vms81.liruilongs.github.io?timeout=10s": dial tcp 192.168.26.81:6443: connect: connection refused
┌──[root@vms81.liruilongs.github.io]-[~]
└─$
「如果不使用systemd系统接管Kubernetes服务的标准输出，则也可以通过日志相关的启动参数来指定日志的存放目录。当然，这里的相关启动参数的配置信息需要通过查看pod文件来查看」
查看kube-controller-manager的启动参数和认证相关的配置文件
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl describe pod kube-controller-manager-vms81.liruilongs.github.io -n kube-system | grep -i -A 20 command
Command:
kube-controller-manager
--allocate-node-cidrs=true
--authentication-kubeconfig=/etc/kubernetes/controller-manager.conf
--authorization-kubeconfig=/etc/kubernetes/controller-manager.conf
--bind-address=127.0.0.1
--client-ca-file=/etc/kubernetes/pki/ca.crt
--cluster-cidr=10.244.0.0/16
--cluster-name=kubernetes
--cluster-signing-cert-file=/etc/kubernetes/pki/ca.crt
--cluster-signing-key-file=/etc/kubernetes/pki/ca.key
--controllers=*,bootstrapsigner,tokencleaner
--kubeconfig=/etc/kubernetes/controller-manager.conf
--leader-elect=true
--port=0
--requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
--root-ca-file=/etc/kubernetes/pki/ca.crt
--service-account-private-key-file=/etc/kubernetes/pki/sa.key
--service-cluster-ip-range=10.96.0.0/12
--use-service-account-credentials=true
State: Running
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl describe pod kube-controller-manager-vms81.liruilongs.github.io -n kube-system | grep kubeconfig
--authentication-kubeconfig=/etc/kubernetes/controller-manager.conf
--authorization-kubeconfig=/etc/kubernetes/controller-manager.conf
--kubeconfig=/etc/kubernetes/controller-manager.conf
/etc/kubernetes/controller-manager.conf from kubeconfig (ro)
kubeconfig:
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl describe pod kube-controller-manager-vms81.liruilongs.github.io -n kube-system | grep -i -A 20 Volumes
Volumes:
ca-certs:
Type: HostPath (bare host directory volume)
Path: /etc/ssl/certs
HostPathType: DirectoryOrCreate
etc-pki:
Type: HostPath (bare host directory volume)
Path: /etc/pki
HostPathType: DirectoryOrCreate
flexvolume-dir:
Type: HostPath (bare host directory volume)
Path: /usr/libexec/kubernetes/kubelet-plugins/volume/exec
HostPathType: DirectoryOrCreate
k8s-certs:
Type: HostPath (bare host directory volume)
Path: /etc/kubernetes/pki
HostPathType: DirectoryOrCreate
kubeconfig:
Type: HostPath (bare host directory volume)
Path: /etc/kubernetes/controller-manager.conf
HostPathType: FileOrCreate
┌──[root@vms81.liruilongs.github.io]-[~]
└─$
「Pod资源对象相关的问题」,比如无法创建Pod, Pod启动后就停止或者Pod副本无法增加,等等。此时,可以先确定Pod在哪个节点上,然后登录这个节点,从kubelet的日志中查询该Pod的完整日志,然后进行问题排查。
「对于与Pod扩容相关或者与RC相关的问题」,则很可能在kube-controller-manager及kube-scheduler的日志中找出问题的关键点。
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl logs kube-scheduler-vms81.liruilongs.github.io
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl logs kube-controller-manager-vms81.liruilongs.github.io
「kube-proxy经常被我们忽视,因为即使它意外停止」, Pod的状态也是正常的,但会导致某些服务访问异常。这些错误通常与每个节点上的kube-proxy服务有着密切的关系。遇到这些问题时,首先要排查kube-proxy服务的日志,同时排查防火墙服务,要特别留意在防火墙中是否有人为添加的可疑规则。
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl logs kube-proxy-tbwz5
常见问题
由于无法下载pause镜像导致Pod一直处于Pending状态
Pod创建成功，但RESTARTS数量持续增加:容器的启动命令不能保持在前台运行。
通过服务名无法访问服务
在Kubernetes集群中应尽量使用服务名访问正在运行的微服务,但有时会访问失败。由于服务涉及服务名的DNS域名解析、kube-proxy组件的负载分发、后端Pod列表的状态等,所以可通过以下几方面排查问题。
「1.查看Service的后端Endpoint是否正常」
可以通过kubectl get endpoints <service name>命令查看某个服务的后端Endpoint列表,如果列表为空,则可能因为:
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 50d
liruilong-kube-prometheus-kubelet ClusterIP None <none> 10250/TCP,10255/TCP,4194/TCP 16d
metrics-server ClusterIP 10.111.104.173 <none> 443/TCP 50d
┌──[root@vms81.liruilongs.github.io]-[~]
└─$kubectl get endpoints
NAME ENDPOINTS AGE
kube-dns 10.244.88.66:53,10.244.88.67:53,10.244.88.66:53 3 more... 50d
liruilong-kube-prometheus-kubelet 192.168.26.81:10250,192.168.26.82:10250,192.168.26.83:10250 6 more... 16d
metrics-server <none> 50d
┌──[root@vms81.liruilongs.github.io]-[~]
└─$
Service的Label Selector与Pod的Label不匹配,沒有相关的pod可以提供能力- 后端
Pod一直没有达到Ready状态(通过kubectl get pods进一步查看Pod的状态) - 「Service的targetPort端口号与Pod的containerPort不一致等」 。即容器暴露的端口不是SVC暴露的端口，需要使用targetPort来转发
「2·查看Service的名称能否被正确解析为ClusterIP地址」
可以通过在客户端容器中ping..svc进行检查,如果能够得到Service的ClusterlP地址,则说明DNS服务能够正确解析Service的名称;如果不能得到Service的ClusterlP地址,则可能是因为Kubernetes集群的DNS服务工作异常。
「3·查看kube-proxy的转发规则是否正确」
我们可以将kube-proxy服务设置为IPVS或iptables负载分发模式。
- 对于
IPVS负载分发模式,可以通过ipvsadm工具查看Node上的IPVS规则,查看是否正确设置Service ClusterlP的相关规则。 - 对于
iptables负载分发模式,可以通过查看Node上的iptables规则,查看是否正确设置Service ClusterlP的相关规则。
寻求帮助
网站和社区 |
|---|
Kubernetes官网中监控、记录和调试相关问题: https://kubernetes.io/docs/tasks/debug-application-cluster/ |
Kubernetes官方论坛: https://discuss.kubernetes.io/(这个需要科学上网) |
GitHub库关于Kubernetes问题列表:https://github.com/kubernetes/kubernetes/issues |
StackOverflow网站上关于Kubernetes的问题讨论：https://stackoverflow.com/questions/tagged/kubernetes |
Kubernetes Slack聊天群组: https://kubernetes.slack.com/(需要谷歌账号) |
