apiserver服务器无法连接端口2379
在升级了 ARM架构Kubernetes 管控服务器，意外发现 apiserver 运行异常:
kubectl get pods --all-namespaces -o wide
显示:
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
...
kube-system kube-apiserver-pi-master1 0/1 CreateContainerError 23 110d 192.168.6.11 pi-master1 <none> <none>
...
kube-system kube-flannel-ds-arm64-dwq86 0/1 Evicted 0 89s <none> jetson <none> <none>
...
kube-system kube-flannel-ds-jcbhq 1/1 Running 0 6h50m 192.168.6.10 jetson <none> <none>
...
kube-system kube-proxy-62sgn 1/1 Running 0 6h50m 192.168.6.10 jetson <none> <none>
不过管控服务器 pi-master1 上其他服务运行正常。
排查
检查 apiserver 日志:
kubectl logs kube-apiserver-pi-master1 -n kube-system
日志显示:
Flag --insecure-port has been deprecated, This flag will be removed in a future version.
I0312 03:29:07.332584 1 server.go:625] external host was not specified, using 192.168.6.11
I0312 03:29:07.333502 1 server.go:163] Version: v1.19.4
I0312 03:29:08.642808 1 plugins.go:158] Loaded 12 mutating admission controller(s) successfully in the following order: NamespaceLifecycle,LimitRanger,ServiceAccount,NodeRestriction,TaintNodesByCondition,Priority,DefaultTolerationSeconds,DefaultStorageClass,StorageObjectInUseProtection,RuntimeClass,DefaultIngressClass,MutatingAdmissionWebhook.
I0312 03:29:08.642890 1 plugins.go:161] Loaded 10 validating admission controller(s) successfully in the following order: LimitRanger,ServiceAccount,Priority,PersistentVolumeClaimResize,RuntimeClass,CertificateApproval,CertificateSigning,CertificateSubjectRestriction,ValidatingAdmissionWebhook,ResourceQuota.
I0312 03:29:08.646102 1 plugins.go:158] Loaded 12 mutating admission controller(s) successfully in the following order: NamespaceLifecycle,LimitRanger,ServiceAccount,NodeRestriction,TaintNodesByCondition,Priority,DefaultTolerationSeconds,DefaultStorageClass,StorageObjectInUseProtection,RuntimeClass,DefaultIngressClass,MutatingAdmissionWebhook.
I0312 03:29:08.646183 1 plugins.go:161] Loaded 10 validating admission controller(s) successfully in the following order: LimitRanger,ServiceAccount,Priority,PersistentVolumeClaimResize,RuntimeClass,CertificateApproval,CertificateSigning,CertificateSubjectRestriction,ValidatingAdmissionWebhook,ResourceQuota.
I0312 03:29:08.652661 1 client.go:360] parsed scheme: "endpoint"
I0312 03:29:08.652792 1 endpoint.go:68] ccResolverWrapper: sending new addresses to cc: [{https://127.0.0.1:2379 <nil> 0 <nil>}]
I0312 03:29:08.681074 1 client.go:360] parsed scheme: "endpoint"
I0312 03:29:08.681309 1 endpoint.go:68] ccResolverWrapper: sending new addresses to cc: [{https://127.0.0.1:2379 <nil> 0 <nil>}]
I0312 03:29:08.710556 1 client.go:360] parsed scheme: "passthrough"
I0312 03:29:08.710685 1 passthrough.go:48] ccResolverWrapper: sending update to cc: {[{https://127.0.0.1:2379 <nil> 0 <nil>}] <nil> <nil>}
I0312 03:29:08.710716 1 clientconn.go:948] ClientConn switching balancer to "pick_first"
I0312 03:29:08.713323 1 client.go:360] parsed scheme: "endpoint"
I0312 03:29:08.713425 1 endpoint.go:68] ccResolverWrapper: sending new addresses to cc: [{https://127.0.0.1:2379 <nil> 0 <nil>}]
...
...
E0312 03:29:19.225719 1 controller.go:152] Unable to remove old endpoints from kubernetes service: StorageError: key not found, Code: 1, Key: /registry/masterleases/192.168.6.11, ResourceVersion: 0, AdditionalErrorMsg:
...
...
W0312 03:48:55.984001 1 clientconn.go:1223] grpc: addrConn.createTransport failed to connect to {https://127.0.0.1:2379 <nil> 0 <nil>}. Err :connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:2379: connect: connection refused". Reconnecting...
...
...
I0312 03:48:55.986358 1 clientconn.go:897] blockingPicker: the picked transport is not ready, loop back to repick
...
...
I0312 03:48:55.993287 1 clientconn.go:897] blockingPicker: the picked transport is not ready, loop back to repick
W0312 03:48:55.993714 1 clientconn.go:1223] grpc: addrConn.createTransport failed to connect to {https://127.0.0.1:2379 <nil> 0 <nil>}. Err :connection error: desc = "transport: Error while dialing dial tcp 127.0.0.1:2379: connect: connection refused". Reconnecting...
I0312 03:48:55.996428 1 controller.go:181] Shutting down kubernetes service endpoint reconciler
I0312 03:48:55.997715 1 controller.go:123] Shutting down OpenAPI controller
...
看起来最初的报错是有关 StorageError ，找不到key文件 /registry/masterleases/192.168.6.11
观察
dmesg -T输出，发现一个奇怪的报错:... [Mon Mar 22 11:01:52 2021] RPC: fragment too large: 1246907721
但是，既然 apiserver 创建失败，但是为何我还能使用
kubectl命令来访问 apiserver 呢？例如，我使用:kubectl get nodes kubectl get pods -o wide -n kubesystem kubectl get pods -o wide -n kube-verify
上述命令都能够正常工作，并且我在回复 部署ARM架构Kubernetes 的Jetson节点时候，完全顺利实现了 从Kubernetes集群删除节点 并重新加回 Jetson 节点。
etcd错误
检查
ps aux | grep apiserver就可以看到，访问端口2379其实就是访问etcd服务:kube-apiserver --advertise-address=192.168.6.11 ... --etcd-servers=https://127.0.0.1:2379 ....
这说明apiserver访问etcd出现错误，很可能就是 etcd 错误导致的。
再次检查 etcd 这个pod:
kubectl get pods -n kube-system -o wide
看到:
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
...
etcd-pi-master1 1/1 Running 18 110d 192.168.6.11 pi-master1 <none> <none>
...
检查 etcd 日志，并没有发现异常错误
kubelet错误
kubenetes #74262 提到可以检查kubelet日志:
journalctl -xeu kubelet
注意， journalctl 参数 -xeu 则日志不换行，有些过长日志不方便检查。可以加上 --no-pager 则直接屏幕打印，可以重定向到 | vim - 检查
我的日志输出确实存在大量报错:
Mar 22 21:05:33 pi-master1 kubelet[1115805]: E0322 21:05:33.780814 1115805 pod_workers.go:191] Error syncing pod 1403dda53affdfee1130475a6d9609da ("kube-apiserver-pi-master1_kube-system(1403dda53affdfee1130475a6d9609da)"), skipping: failed to "StartContainer" for "kube-apiserver" with CreateContainerError: "Error response from daemon: Conflict. The container name \"/k8s_kube-apiserver_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_24\" is already in use by
container \"eced8537863007db9a915924785306b26238cabbd3feec0e5226e2ad0710807b\". You have to remove (or rename) that container to be able to reuse that name."
原来启动容器命名出现了重名，之前的 kube-apiserver-pi-master1 尚未清理导致无法启动相同名字的容器
检查
docker ps --all查看是否有同名残留:docker ps --all | grep kube-apiserver-pi-master1
可以看到:
8470235abd66 4958a2396b16 "kube-apiserver --ad…" 10 days ago Exited (0) 10 days ago k8s_kube-apiserver_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_23
eced85378630 4958a2396b16 "kube-apiserver --ad…" 10 days ago Up 10 days k8s_kube-apiserver_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_24
07637544b672 k8s.gcr.io/pause:3.2 "/pause" 10 days ago Up 10 days k8s_POD_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_17
46497b3b5724 k8s.gcr.io/pause:3.2 "/pause" 10 days ago Exited (0) 10 days ago k8s_POD_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_15
尝试删除已经退出的容器:
sudo docker rm 8470235abd66 sudo docker rm 46497b3b5724
果然，现在
apiserver容器能够正常创建了:kubectl get pods -o wide -n kube-system
显示正常运行:
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
...
kube-apiserver-pi-master1 1/1 Running 24 4h8m 192.168.6.11 pi-master1 <none> <none>
再次检查系统中存在退出但是没有清理的docker容器:
sudo docker ps --all | grep Exited
然后检查确定后做清理:
sudo docker ps --all | grep Exited | awk '{print $1}' | xargs sudo docker rm
推测
我注意到kubernetes升级，下一个 kubernetes apiserver 容器命名是后缀是依次递增的，这点可以从 docker ps --all 看到:
k8s_kube-apiserver_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_23
k8s_kube-apiserver_kube-apiserver-pi-master1_kube-system_1403dda53affdfee1130475a6d9609da_24
也就是说如果有一个升级过程中 kube-apiserver...24 意外退出，则升级程序还会重新尝试用同一个容器名创建启动，这就在docker上导致冲突
看来连接 etcd 端口失败仅仅是表象，实际排查故障还是需要从 kubelet 日志着手。