Kubernetes中Nginx服务启动失败如何排查

时间：2023-05-24 11:50

❌pod节点启动失败，nginx服务无法正常访问，服务状态显示为ImagePullBackOff。

[root@m1 ~]# kubectl get podsNAME                    READY   STATUS             RESTARTS   AGEnginx-f89759699-cgjgp   0/1     ImagePullBackOff   0          103m

查看nginx服务的Pod节点详细信息。

[root@m1 ~]# kubectl describe pod nginx-f89759699-cgjgpName:             nginx-f89759699-cgjgpNamespace:        defaultPriority:         0Service Account:  defaultNode:             n1/192.168.200.84Start Time:       Fri, 10 Mar 2023 08:40:33 +0800Labels:           app=nginx                  pod-template-hash=f89759699Annotations:      <none>Status:           PendingIP:               10.244.3.20IPs:  IP:           10.244.3.20Controlled By:  ReplicaSet/nginx-f89759699Containers:  nginx:    Container ID:       Image:          nginx    Image ID:           Port:           <none>    Host Port:      <none>    State:          Waiting      Reason:       ImagePullBackOff    Ready:          False    Restart Count:  0    Environment:    <none>    Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-zk8sj (ro)Conditions:  Type              Status  Initialized       True   Ready             False   ContainersReady   False   PodScheduled      True Volumes:  default-token-zk8sj:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-zk8sj    Optional:    falseQoS Class:       BestEffortNode-Selectors:  <none>Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300sEvents:  Type     Reason   Age                     From     Message  ----     ------   ----                    ----     -------  Normal   BackOff  57m (x179 over 100m)    kubelet  Back-off pulling image "nginx"  Normal   Pulling  7m33s (x22 over 100m)   kubelet  Pulling image "nginx"  Warning  Failed   2m30s (x417 over 100m)  kubelet  Error: ImagePullBackOff

发现，获取nginx镜像失败。可能是由于Docker服务引起的。

于是，检查Docker是否正常启动

systemctl status docker

发现，docker服务启动失败????，手动尝试重新启动。

systemctl restart docker

但是，重启docker服务失败，出现如下报错信息。

[root@m1 ~]# systemctl restart dockerJob for docker.service failed because the control process exited with error code.See "systemctl status docker.service" and "journalctl -xe" for details.

执行systemctl restart docker命令失效。

接着，当执行docker version命令时，发现未能连接到Docker daemon

[root@m1 ~]# docker versionClient: Docker Engine - Community Version:           20.10.17 API version:       1.41 Go version:        go1.17.11 Git commit:        100c701 Built:             Mon Jun  6 23:03:11 2022 OS/Arch:           linux/amd64 Context:           default Experimental:      trueCannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

于是，再次通过执行systemctl status docker命令，查看docker服务未能启动，阅读输出报错信息，如下所示。

[root@m1 ~]# systemctl status docker● docker.service - Docker Application Container Engine   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)   Active: failed (Result: exit-code) since Fri 2023-03-10 10:28:16 CST; 4min 35s ago     Docs: https://docs.docker.com Main PID: 2221 (code=exited, status=1/FAILURE)Mar 10 10:28:13 m1 systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILUREMar 10 10:28:13 m1 systemd[1]: docker.service: Failed with result 'exit-code'.Mar 10 10:28:13 m1 systemd[1]: Failed to start Docker Application Container Engine.Mar 10 10:28:16 m1 systemd[1]: docker.service: Service RestartSec=2s expired, scheduling restart.Mar 10 10:28:16 m1 systemd[1]: docker.service: Scheduled restart job, restart counter is at 3.Mar 10 10:28:16 m1 systemd[1]: Stopped Docker Application Container Engine.Mar 10 10:28:16 m1 systemd[1]: docker.service: Start request repeated too quickly.Mar 10 10:28:16 m1 systemd[1]: docker.service: Failed with result 'exit-code'.Mar 10 10:28:16 m1 systemd[1]: Failed to start Docker Application Container Engine.[root@m1 ~]#

通过上述输出显示，Docker 服务进程的启动失败，状态为 1/FAILURE。

✅接下来，尝试通过以下步骤来排查和解决问题：

1️⃣查看 Docker 服务日志：使用以下命令查看 Docker 服务日志，以便更详细地了解失败原因。

sudo journalctl -u docker.service

Kubernetes中Nginx服务启动失败如何排查

2️⃣ 通过输出Ddocker日志分析，提取到了相关报错信息片段，发现是配置daemon中的/etc/docker/daemon.json配置文件出错导致的。

Mar 10 10:20:17 m1 systemd[1]: Starting Docker Application Container Engine...Mar 10 10:20:17 m1 dockerd[1572]: unable to configure the Docker daemon with file /etc/docker/daemon.json: invalid character '"' after object key:value pairMar 10 10:20:17 m1 systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILUREMar 10 10:20:17 m1 systemd[1]: docker.service: Failed with result 'exit-code'.Mar 10 10:20:17 m1 systemd[1]: Failed to start Docker Application Container Engine.Mar 10 10:20:19 m1 systemd[1]: docker.service: Service RestartSec=2s expired, scheduling restart.Mar 10 10:20:19 m1 systemd[1]: docker.service: Scheduled restart job, restart counter is at 2.Mar 10 10:20:19 m1 systemd[1]: Stopped Docker Application Container Engine.

3️⃣此时，查看daemon配置文件/etc/docker/daemon.json是否配置正确。

[root@m1 ~]# cat /etc/docker/daemon.json{	  # 设置 Docker 镜像的注册表镜像源为阿里云镜像源。  "registry-mirrors": ["https://w2kavmmf.mirror.aliyuncs.com"]  # 指定 Docker 守护进程使用 systemd 作为 cgroup driver。  "exec-opts": ["native.cgroupdriver=systemd"]}

咋一看，配置信息没有什么问题，都是正确的，但仔细一看，就会发现应该在"registry-mirrors"选项的结尾添加逗号。犯了缺少逗号（,）导致的语法错误，终于找到了问题根源。

修改后：

[root@m1 ~]# cat /etc/docker/daemon.json{  "registry-mirrors": ["https://w2kavmmf.mirror.aliyuncs.com"],  "exec-opts": ["native.cgroupdriver=systemd"]}[root@m1 ~]# cat /etc/docker/daemon.json{  "registry-mirrors": ["https://w2kavmmf.mirror.aliyuncs.com"],  "exec-opts": ["native.cgroupdriver=systemd"]}

按下:wq报错退出。

4️⃣ 重新加载系统并重新启动Docker服务

systemctl daemon-reloadsystemctl restart dockersystemctl status docker

5️⃣检查docker版本信息是否输出正常

[root@m1 ~]# docket version-bash: docket: command not found[root@m1 ~]# docker versionClient: Docker Engine - Community Version:           20.10.17 API version:       1.41 Go version:        go1.17.11 Git commit:        100c701 Built:             Mon Jun  6 23:03:11 2022 OS/Arch:           linux/amd64 Context:           default Experimental:      trueServer: Docker Engine - Community Engine:  Version:          20.10.17  API version:      1.41 (minimum version 1.12)  Go version:       go1.17.11  Git commit:       a89b842  Built:            Mon Jun  6 23:01:29 2022  OS/Arch:          linux/amd64  Experimental:     false containerd:  Version:          1.6.6  GitCommit:        10c12954828e7c7c9b6e0ea9b0c02b01407d3ae1 runc:  Version:          1.1.2  GitCommit:        v1.1.2-0-ga916309 docker-init:  Version:          0.19.0  GitCommit:        de40ad0

[root@m1 ~]# docker infoClient: Context:    default Debug Mode: false Plugins:  app: Docker App (Docker Inc., v0.9.1-beta3)  buildx: Docker Buildx (Docker Inc., v0.8.2-docker)  scan: Docker Scan (Docker Inc., v0.17.0)Server: Containers: 20  Running: 8  Paused: 0  Stopped: 12 Images: 20 Server Version: 20.10.17 Storage Driver: overlay2  Backing Filesystem: xfs  Supports d_type: true  Native Overlay Diff: true  userxattr: false Logging Driver: json-file Cgroup Driver: systemd Cgroup Version: 1 Plugins:  Volume: local  Network: bridge host ipvlan macvlan null overlay  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog Swarm: inactive Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc Default Runtime: runc Init Binary: docker-init containerd version: 10c12954828e7c7c9b6e0ea9b0c02b01407d3ae1 runc version: v1.1.2-0-ga916309 init version: de40ad0 Security Options:  seccomp   Profile: default Kernel Version: 4.18.0-372.9.1.el8.x86_64 Operating System: Rocky Linux 8.6 (Green Obsidian) OSType: linux Architecture: x86_64 CPUs: 2 Total Memory: 9.711GiB Name: m1 ID: 4YIS:FHSB:YXRI:CED5:PJSJ:EAS2:BCR3:GJJF:FDPK:EDJH:DVKU:AIYJ Docker Root Dir: /var/lib/docker Debug Mode: false Registry: https://index.docker.io/v1/ Labels: Experimental: false Insecure Registries:  127.0.0.0/8 Registry Mirrors:  https://w2kavmmf.mirror.aliyuncs.com/ Live Restore Enabled: false

至此，Docker服务重启成功，pod节点恢复正常，Nginx服务能够正常访问。

[root@m1 ~]# kubectl get podsNAME                    READY   STATUS    RESTARTS   AGEnginx-f89759699-cgjgp   1/1     Running   0          174m

查看pod详细信息，显示正常。

[root@m1 ~]# kubectl describe pod nginx-f89759699-cgjgpName:             nginx-f89759699-cgjgpNamespace:        defaultPriority:         0Service Account:  defaultNode:             n1/192.168.200.84Start Time:       Fri, 10 Mar 2023 08:40:33 +0800Labels:           app=nginx                  pod-template-hash=f89759699Annotations:      <none>Status:           RunningIP:               10.244.3.20IPs:  IP:           10.244.3.20Controlled By:  ReplicaSet/nginx-f89759699Containers:  nginx:    Container ID:   docker://88bdc2bfa592f60bf99bac2125b0adae005118ae8f2f271225245f20b7cfb3c8    Image:          nginx    Image ID:       docker-pullable://nginx@sha256:aa0afebbb3cfa473099a62c4b32e9b3fb73ed23f2a75a65ce1d4b4f55a5c2ef2    Port:           <none>    Host Port:      <none>    State:          Running      Started:      Fri, 10 Mar 2023 10:37:42 +0800    Ready:          True    Restart Count:  0    Environment:    <none>    Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-zk8sj (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  default-token-zk8sj:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-zk8sj    Optional:    falseQoS Class:       BestEffortNode-Selectors:  <none>Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300sEvents:  Type    Reason   Age                   From     Message  ----    ------   ----                  ----     -------  Normal  BackOff  58m (x480 over 171m)  kubelet  Back-off pulling image "nginx"[root@m1 ~]#

Kubernetes中Nginx服务启动失败如何排查