❌pod節點啟動失敗，nginx服務無法正常訪問，服務狀態顯示為ImagePullBackOff。
[root@m1 ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-f89759699-cgjgp 0/1 ImagePullBackOff 0 103m
查看nginx服務的Pod節點詳細資訊。
[root@m1 ~]# kubectl describe pod nginx-f89759699-cgjgp
Name: nginx-f89759699-cgjgp
Namespace: default
Priority: 0
Service Account: default
Node: n1/192.168.200.84
Start Time: Fri, 10 Mar 2023 08:40:33 +0800
Labels: app=nginx
pod-template-hash=f89759699
Annotations: <none>
Status: Pending
IP: 10.244.3.20
IPs:
IP: 10.244.3.20
Controlled By: ReplicaSet/nginx-f89759699
Containers:
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: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
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發現，取得nginx鏡像失敗。可能是由於Docker服務引起的。
於是，檢查Docker是否正常啟動
systemctl status docker
發現，docker服務啟動失敗????，手動嘗試重新啟動。
systemctl restart docker
但是，重新啟動docker服務失敗，出現如下報錯訊息。
[root@m1 ~]# systemctl restart docker Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.
執行systemctl restart docker指令失效。
接著，當執行docker version指令時，發現未能連接到Docker daemon
[root@m1 ~]# docker version Client: 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: true Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
於是，再次透過執行systemctl status docker指令，查看docker服務未能啟動，閱讀輸出報錯訊息，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/FAILURE
Mar 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 ~]#透過上述輸出顯示，Docker 服務程序的啟動失敗，狀態為 1/FAILURE。
✅接下來，嘗試透過以下步驟來排查和解決問題：
1️⃣查看 Docker 服務日誌：使用以下命令查看 Docker 服務日誌，以便更詳細地了解失敗原因。
sudo journalctl -u docker.service
2️⃣ 透過輸出Ddocker日誌分析，提取到了相關報錯資訊片段，發現是配置daemon中的/etc/docker/daemon.json設定檔出錯導致的。
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 pair Mar 10 10:20:17 m1 systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILURE Mar 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此時，查看daemon設定檔/etc/docker/daemon.json是否配置正確。
[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，設定資訊沒有什麼問題，都是正確的，但仔細一看，就會發現應該在"registry-mirrors"選項的結尾加上逗號。犯了缺少逗號（,）導致的文法錯誤，終於找到了問題根源。
修改後：
[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報錯誤退出。
4️⃣ 重新載入系統並重新啟動Docker服務
systemctl daemon-reload systemctl restart docker systemctl status docker
5️⃣檢查docker版本資訊是否輸出正常
[root@m1 ~]# docket version -bash: docket: command not found [root@m1 ~]# docker version Client: 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: true Server: 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 info Client: 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服務重啟成功，Nginxpod節點恢復正常，Nginxpod節點恢復正常，Nginxpod節點恢復正常，Nginxpod節點恢復正常，Nginxpod節點恢復正常，Nginxpod節點恢復正常，Nginxpod節點恢復正常，服務能夠正常存取。
[root@m1 ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-f89759699-cgjgp 1/1 Running 0 174m
查看pod詳細信息，顯示正常。
[root@m1 ~]# kubectl describe pod nginx-f89759699-cgjgp
Name: nginx-f89759699-cgjgp
Namespace: default
Priority: 0
Service Account: default
Node: n1/192.168.200.84
Start Time: Fri, 10 Mar 2023 08:40:33 +0800
Labels: app=nginx
pod-template-hash=f89759699
Annotations: <none>
Status: Running
IP: 10.244.3.20
IPs:
IP: 10.244.3.20
Controlled By: ReplicaSet/nginx-f89759699
Containers:
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: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal BackOff 58m (x480 over 171m) kubelet Back-off pulling image "nginx"
[root@m1 ~]#
以上是Kubernetes中Nginx服務啟動失敗如何排查的詳細內容。更多資訊請關注PHP中文網其他相關文章！
