想把容器当做虚拟机使用，通过k8s创建centos:7 时，准备看下sshd的状态结果报错如下：
[root@centos7-5f547bd9c4-9pt84 /]# systemctl status sshd Failed to get D-Bus connection: Operation not permitted
研究发现，容器内部的root是个空壳子的root，说白了就是没有root权限的root，想要容器内不的root拥有root权限，必须加上--privileged=true 这个参数，
--- apiVersion: apps/v1 kind: Deployment metadata: annotations: {} labels: k8s.kuboard.cn/name: centos7 name: centos7 namespace: default resourceVersion: '3857415' spec: progressDeadlineSeconds: 600 replicas: 1 revisionHistoryLimit: 10 selector: matchLabels: k8s.kuboard.cn/name: centos7 strategy: rollingUpdate: maxSurge: 25% maxUnavailable: 25% type: RollingUpdate template: metadata: creationTimestamp: null labels: k8s.kuboard.cn/name: centos7 spec: containers: - command: - /sbin/init - '-c' - '--' image: 'centos:7' imagePullPolicy: IfNotPresent name: centos7 resources: {} securityContext: privileged: true terminationMessagePath: /dev/termination-log terminationMessagePolicy: File dnsPolicy: ClusterFirst restartPolicy: Always schedulerName: default-scheduler securityContext: {} terminationGracePeriodSeconds: 30
yum install -y openssh-server systemctl restart sshd
加完之后，就可以使用systemd了，验证如下：
[root@centos7-564659f79d-nwrq6 /]# systemctl status sshd ● sshd.service - OpenSSH server daemon Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2022-12-12 06:45:09 UTC; 14s ago Docs: man:sshd(8) man:sshd_config(5) Main PID: 173 (sshd) CGroup: /system.slice/containerd.service/kubepods-besteffort-poda1ddf453_58fc_495b_ba4c_c94844522f3e.slice:cri-containerd:43b67802d92b3240d128d2d3a1ae05df781933d004f7db3fc815dfbb85d1d1c0/system.slice/sshd.service └─173 /usr/sbin/sshd -D ‣ 173 /usr/sbin/sshd -D Dec 12 06:45:09 centos7-564659f79d-nwrq6 systemd[1]: Starting OpenSSH server daemon... Dec 12 06:45:09 centos7-564659f79d-nwrq6 sshd[173]: Server listening on 0.0.0.0 port 22. Dec 12 06:45:09 centos7-564659f79d-nwrq6 sshd[173]: Server listening on :: port 22. Dec 12 06:45:09 centos7-564659f79d-nwrq6 systemd[1]: Started OpenSSH server daemon.
可以看到现在能正常使用systemd了。
